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polymer versus lead type

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  • kringds
    I have read many times that with polymer plates you have to be much more precise in the setting of the roller heights (on a platen press at least) than with
    Message 1 of 28 , Jan 31, 2014
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      I have read many times that with polymer plates you have to be much more precise in the setting of the roller heights (on a platen press at least) than with lead type. Why is this so? Is it because the edges of the letterforms are sharper on lead, so that you can hit them with the rollers a little harder without showing any slur? Or does it have to do with the material? Does the ink transfer easier to lead than to polymer?

      thank you,
      bryan kring
    • Scott Rubel
      It s because the polymer washes out and leaves a bevel from the surface to the base. If the rollers are too low, they ink the sides of the type. With lead,
      Message 2 of 28 , Jan 31, 2014
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        It's because the polymer washes out and leaves a bevel from the surface to the base. If the rollers are too low, they ink the "sides" of the type. With lead, the sides are almost at right angles and maladjusted rollers will not so much ink the sides. Lead type always looks cleaner no matter what you do.

        --Scott

        On Jan 31, 2014, at 9:45 AM, bryan@... wrote:



        I have read many times that with polymer plates you have to be much more precise in the setting of the roller heights (on a platen press at least) than with lead type. Why is this so? Is it because the edges of the letterforms are sharper on lead, so that you can hit them with the rollers a little harder without showing any slur? Or does it have to do with the material? Does the ink transfer easier to lead than to polymer?

        thank you,
        bryan kring



      • Peter Fraterdeus
        Stiffness of the ink also makes a huge difference. In general, while one may indeed be able to get away with it depending on the form, getting the roller set
        Message 3 of 28 , Jan 31, 2014
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          Stiffness of the ink also makes a huge difference.
          In general, while one may indeed be able to get away with it depending on the form, getting the roller set correctly is no less critical with either.

          IMHO
          Peter

          •~^~•~*~•~^~•~*~•~^~•~*~•
          Peter Fraterdeus
          Slowprint.com / Semiotx.com
          google voice 1 563 223 8231
          peterf@...
          From Phone plz excuse brevity!

          On January 31, 2014 11:51:46 AM Scott Rubel <scott@...> wrote:

          It's because the polymer washes out and leaves a bevel from the surface to the base. If the rollers are too low, they ink the "sides" of the type. With lead, the sides are almost at right angles and maladjusted rollers will not so much ink the sides. Lead type always looks cleaner no matter what you do.

          --Scott

          On Jan 31, 2014, at 9:45 AM, bryan@... wrote:



          I have read many times that with polymer plates you have to be much more precise in the setting of the roller heights (on a platen press at least) than with lead type. Why is this so? Is it because the edges of the letterforms are sharper on lead, so that you can hit them with the rollers a little harder without showing any slur? Or does it have to do with the material? Does the ink transfer easier to lead than to polymer?

          thank you,
          bryan kring



        • Kathleen Whalen
          Type high bearers pretty much take care of this. You¹ll figure out yourself how fussy you are happy with being, as soon as you gain experience with the
          Message 4 of 28 , Jan 31, 2014
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            Re: [PPLetterpress] polymer versus lead type Type high bearers pretty much take care of this.

            You’ll figure out yourself how fussy you are happy with being, as soon as you gain experience with the printed images.


            Graham Moss
            Incline Press
            36 Bow Street
            Oldham OL1 1SJ  England

            http://www.inclinepress.com
            news blog: http://www.inclinepress.wordpress.com



            I have read many times that with polymer plates you have to be much more precise in the setting of the roller heights (on a platen press at least) than with lead type. Why is this so? Is it because the edges of the letterforms are sharper on lead, so that you can hit them with the rollers a little harder without showing any slur? Or does it have to do with the material? Does the ink transfer easier to lead than to polymer?
            thank you,
            bryan kring










          • Peter Fraterdeus
            Of course, if your form is made up of (say) wood type, hand-cut lino, and foundry, you ll never get the rollers set right until all the matter is leveled, and
            Message 5 of 28 , Jan 31, 2014
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              Of course, if your form is made up of (say) wood type, hand-cut lino, and foundry, you'll never get the rollers set right until all the matter is leveled, and that may not be at the canonical 'type-high'. This is why bearers need to be adjustable unless you're really only doing one kind of work, I suppose.

              PF

              On 31 Jan 2014, at 12:24 PM, Kathleen Whalen wrote:



              Type high bearers pretty much take care of this. 

              You’ll figure out yourself how fussy you are happy with being, as soon as you gain experience with the printed images.


              Graham Moss
              Incline Press
              36 Bow Street
              Oldham OL1 1SJ  England

              http://www.inclinepress.com
              news blog: http://www.inclinepress.wordpress.com



              I have read many times that with polymer plates you have to be much more precise in the setting of the roller heights (on a platen press at least) than with lead type. Why is this so? Is it because the edges of the letterforms are sharper on lead, so that you can hit them with the rollers a little harder without showing any slur? Or does it have to do with the material? Does the ink transfer easier to lead than to polymer?
              thank you,
              bryan kring













            • Incline Press
              ... news blog: http://www.inclinepress.wordpress.com ... Re: [PPLetterpress] polymer versus lead type Exactly so for my fussyness, that would potentially be
              Message 6 of 28 , Jan 31, 2014
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                Re: [PPLetterpress] polymer versus lead type
                Exactly so – for my fussyness, that would potentially be three separate runs, and only experience determines how the printer approaches such a situation  (or even allows such a forme to come into existence!) .

                But we are drifting away from the original issue! A straight polymer forme, like a straight type forme, is well-served by bearers of the same height as the job in the press, and the amount of beard on metal or polymer is thereby rendered immaterial.

                Graham Moss



                news blog: http://www.inclinepress.wordpress.com






                Of course, if your form is made up of (say) wood type, hand-cut lino, and foundry, you'll never get the rollers set right until all the matter is leveled, and that may not be at the canonical 'type-high'. This is why bearers need to be adjustable unless you're really only doing one kind of work, I suppose.
                PF
                On 31 Jan 2014, at 12:24 PM, Kathleen Whalen wrote:

                Type high bearers pretty much take care of this. 
                You
                ll figure out yourself how fussy you are happy with being, as soon as you gain experience with the printed images.
                Graham Moss
                Incline Press
                36 Bow Street
                Oldham OL1 1SJ  England



              • Kevin Martin
                But then bearers, as I understand them (in that the form rollers run on them, not the trucks, which run on the rails) won t have much effect if the form roller
                Message 7 of 28 , Jan 31, 2014
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                  Re: [PPLetterpress] polymer versus lead type

                  But then bearers, as I understand them (in that the form rollers run on them, not the trucks, which run on the rails) won’t have much effect if the form roller is soft. The bearer will sink into the rollers but will not substantially raise the rollers overall, any more than the plunger on a numbering machine would.

                   

                  -Kevin Martin

                  the Papertrail Handmade Paper & Book Arts

                  New Dundee, Ontario

                  www.papertrail.ca

                   

                   

                   

                  From: PPLetterpress@yahoogroups.com [mailto:PPLetterpress@yahoogroups.com] On Behalf Of Incline Press
                  Sent: Friday, January 31, 2014 2:51 PM
                  To: PPLetterpress@yahoogroups.com
                  Subject: Re: [PPLetterpress] polymer versus lead type

                   




                  Exactly so – for my fussyness, that would potentially be three separate runs, and only experience determines how the printer approaches such a situation  (or even allows such a forme to come into existence!) .

                  But we are drifting away from the original issue! A straight polymer forme, like a straight type forme, is well-served by bearers of the same height as the job in the press, and the amount of beard on metal or polymer is thereby rendered immaterial.

                  Graham Moss



                  news blog: http://www.inclinepress.wordpress.com





                  Of course, if your form is made up of (say) wood type, hand-cut lino, and foundry, you'll never get the rollers set right until all the matter is leveled, and that may not be at the canonical 'type-high'. This is why bearers need to be adjustable unless you're really only doing one kind of work, I suppose.
                  PF

                  On 31 Jan 2014, at 12:24 PM, Kathleen Whalen wrote:

                  Type high bearers pretty much take care of this. 
                  You
                  ll figure out yourself how fussy you are happy with being, as soon as you gain experience with the printed images.
                  Graham Moss
                  Incline Press
                  36 Bow Street
                  Oldham OL1 1SJ  England







                • Incline Press
                  Soft forme rollers? You must be joking! This might sound like a problem in theory Kevin, but it never has been in practise. I¹d be amused to hear actual
                  Message 8 of 28 , Feb 1, 2014
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                    Re: [PPLetterpress] polymer versus lead type


                    Soft forme rollers? You must be joking!

                    This might sound like a problem in theory Kevin, but it never has been in practise. I’d be amused to hear actual occurences of the other experience.


                    Graham Moss
                    Incline Press
                    36 Bow Street
                    Oldham OL1 1SJ  England

                    http://www.inclinepress.com
                    news blog: http://www.inclinepress.wordpress.com






                    But then bearers, as I understand them (in that the form rollers run on them, not the trucks, which run on the rails) won’t have much effect if the form roller is soft. The bearer will sink into the rollers but will not substantially raise the rollers overall, any more than the plunger on a numbering machine would.
                     
                    -Kevin Martin



                  • parallel_imp
                    Roller bearers don t do much in regard to roller HEIGHT setting. They can have a real effect on roller motion, which is a serious problem with photopolymer,
                    Message 9 of 28 , Feb 1, 2014
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                      Roller bearers don't do much in regard to roller HEIGHT setting. They can have a real effect on roller motion, which is a serious problem with photopolymer, magnified by differences in roller and truck diameter on a platen, causing slur. But they don't do much at all to lift soft rollers. When used on a proof press with automatic inking, I think the effect of bearers is more to equalize impression, which is why it was standard practice when pulling repro proofs. The reason Kelsey sold so many sets of wide roller bearers is because they had one style of roller truck that was not keyed to the shaft and just turned loosely: crazy slur.

                      When I started printing it was just metal type and plates and the odd linoleum cut, all easily inked using my Dad's and my teacher's method, which was to inspect the image left on the roller after it passes the form, look at the print, and then adjust the Morgan truck accordingly. This did not work when I added photopolymer plates to the process, in large part because the harder contact wanted by a metal form was too much for photopolymer and the over expansion of Morgans in compensation lead to eccentricity, which causes the wandering ink densities that have been questioned so often online. Eventually I realized it was a more complicated relationship between roller and plate surface, and truck and track, because the photopolymer plate does not grab the roller as a metal form does, it slips; some pre-photopolymer authors tell you to keep the trucks smaller than the roller so the form will grab the roller and make it turn. Do that with photopolymer and all you will get is ghosting, slurred leading and trailing edges and ink wiped onto the edge of the plate. With very hard rollers I found that using ornamental bearers grabbed the roller and got it turning at speed before it hit the form: with photopolymer the rollers must roll over the entire form at even speed, no slippage anywhere. That's easier on a Vandercook with geared form rollers than it is on most platens.

                      Eric Holub, SF



                      ---In PPLetterpress@yahoogroups.com, <kwhalen.incline@...> wrote:

                      Re: [PPLetterpress] polymer versus lead type Type high bearers pretty much take care of this.

                      You’ll figure out yourself how fussy you are happy with being, as soon as you gain experience with the printed images.


                      Graham Moss
                      Incline Press
                      36 Bow Street
                      Oldham OL1 1SJ  England

                      http://www.inclinepress.com
                      news blog: http://www.inclinepress.wordpress.com



                      I have read many times that with polymer plates you have to be much more precise in the setting of the roller heights (on a platen press at least) than with lead type. Why is this so? Is it because the edges of the letterforms are sharper on lead, so that you can hit them with the rollers a little harder without showing any slur? Or does it have to do with the material? Does the ink transfer easier to lead than to polymer?
                      thank you,
                      bryan kring










                    • Jason Dewinetz
                      Graham, I ve had issues along the lines of what Kevin s mentioned. I have an SP-25 Power, which has, obviously, 25-inch rollers. I had them re-covered a year
                      Message 10 of 28 , Feb 1, 2014
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                        Graham, I’ve had issues along the lines of what Kevin’s mentioned. I have an SP-25 Power, which has, obviously, 25-inch rollers. I had them re-covered a year or two ago, and they arrived with the softer (blue) rubber. I’ve had trouble with them from the day they arrived, as the rubber is much softer than the stiffer black covering I have on the rollers for my 15-21. The main issue is that the weight of the rider-rollers causes the middle of the rubber rollers to sag. When I use my roller gauge to set the rollers, there is a very significant drop in the middle third of the rollers, to the extent that 6-inches in from each end I get no ink on the gauge, while in the middle I get more than 1/8-inch. I’ve attempted to use three 12pt type-high rules on either side of the sheet as roller bearers, which definitely helps, but the rollers still reads inconsistently because they do, in fact, allow the bearers to press into them so that the actual height of the roller ends up lower than the height of the bearers. I’ve given up and will have to get the rollers covered again, because the softer blue rubber has been nothing but trouble.

                         

                        ________________

                        Jason Dewinetz

                        Greenboathouse Press

                        www.greenboathouse.com

                         

                         

                         

                        From: PPLetterpress@yahoogroups.com [mailto:PPLetterpress@yahoogroups.com] On Behalf Of Incline Press
                        Sent: February-01-14 1:29 AM
                        To: PPLetterpress@yahoogroups.com
                        Subject: Re: [PPLetterpress] polymer versus lead type

                         

                         




                        Soft forme rollers? You must be joking!

                        This might sound like a problem in theory Kevin, but it never has been in practise. I’d be amused to hear actual occurences of the other experience.


                        Graham Moss
                        Incline Press
                        36 Bow Street
                        Oldham OL1 1SJ  England

                        http://www.inclinepress.com
                        news blog: http://www.inclinepress.wordpress.com






                        But then bearers, as I understand them (in that the form rollers run on them, not the trucks, which run on the rails) won’t have much effect if the form roller is soft. The bearer will sink into the rollers but will not substantially raise the rollers overall, any more than the plunger on a numbering machine would.
                         
                        -Kevin Martin


                      • Incline Press
                        But nothing would solve this Jason, but new rollers. And no matter whether printing type or polymer, with your rollers the problem would remain; if they sag
                        Message 11 of 28 , Feb 1, 2014
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                          Re: [PPLetterpress] polymer versus lead type

                          But nothing would solve this Jason, but new rollers. And no matter whether printing type or polymer, with your rollers the problem would remain; if they sag like that, then there is no ability to gain ‘proper adjustment’ of the rollers by any means.

                          This is quite a different matter from the issue posited in the first posting - (I mean, in the UK we say that you have moved the goal-posts. Yes?). With the proper rollers, I would still recommend using roller bearers as it will solve the issue of inking the beard on the type/edges of the polymer plate. But yes, there is no substitute for getting the rollers made properly in the first place.

                          My roller bearers are 5 ems wide, and were manufactured for the purpose by Cornerhouse, a reputable UK manufacturer of all sorts of sundries for letterpress. I would not recommend use of 3-em bearers. Rather than a fistful of slugs, I’d recommend getting a set made out of brass by a miller who can work to proper tolerences. But yes, sort out the rollers first.


                          Graham Moss
                          Incline Press

                          news blog: http://www.inclinepress.wordpress.com










                          Graham, I
                          ’ve had issues along the lines of what Kevin’s mentioned. I have an SP-25 Power, which has, obviously, 25-inch rollers. I had them re-covered a year or two ago, and they arrived with the softer (blue) rubber. I’ve had trouble with them from the day they arrived, as the rubber is much softer than the stiffer black covering I have on the rollers for my 15-21. The main issue is that the weight of the rider-rollers causes the middle of the rubber rollers to sag. When I use my roller gauge to set the rollers, there is a very significant drop in the middle third of the rollers, to the extent that 6-inches in from each end I get no ink on the gauge, while in the middle I get more than 1/8-inch. I’ve attempted to use three 12pt type-high rules on either side of the sheet as roller bearers, which definitely helps, but the rollers still reads inconsistently because they do, in fact, allow the bearers to press into them so that the actual height of the roller ends up lower than the height of the bearers. I’ve given up and will have to get the rollers covered again, because the softer blue rubber has been nothing but trouble.
                           
                          ________________
                          Jason Dewinetz
                          Greenboathouse Press
                          www.greenboathouse.com



                        • Gerald Lange
                          I notice there is a tendency to buy rollers on the cheap. Not sure why since the more expensive rollers aren t all that much more expensive. Especially
                          Message 12 of 28 , Feb 1, 2014
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                            I notice there is a tendency to buy rollers on the cheap. Not sure why since the more expensive rollers aren't all that much more expensive. Especially considering what folks charge for their printed work.

                            The roller manufacturer that Vandercook was using, at least toward the end, was Ideal, now RotaDyne (they have several locations). They are listed in the Links section here. RotaDyne has the original Vandercook specs. I use them and trust them

                            Rollers do need to be slightly harder for printing with photopolymer. Ask for 25. There are a number of reasons for this. There is no mystery and voodoo (though one might thinks so reading all the superstitions and opinions being bandied about), there is a lot of good and accurate information out there and I am not referring to the maelstrom that is the internet.

                            If your press is true and set up properly, and you use quality bases and plates with correct makeready and presswork, there will be no tears, no frustration. With the prices that Vandercooks demand these days it is absolutely curious why folks pinch money on accessories, tools, etc.

                            Gerald
                            http://BielerPressxi.blogspot


                            On 2/1/14 9:43 AM, Jason Dewinetz wrote:  

                            Graham, I’ve had issues along the lines of what Kevin’s mentioned. I have an SP-25 Power, which has, obviously, 25-inch rollers. I had them re-covered a year or two ago, and they arrived with the softer (blue) rubber. I’ve had trouble with them from the day they arrived, as the rubber is much softer than the stiffer black covering I have on the rollers for my 15-21. The main issue is that the weight of the rider-rollers causes the middle of the rubber rollers to sag. When I use my roller gauge to set the rollers, there is a very significant drop in the middle third of the rollers, to the extent that 6-inches in from each end I get no ink on the gauge, while in the middle I get more than 1/8-inch. I’ve attempted to use three 12pt type-high rules on either side of the sheet as roller bearers, which definitely helps, but the rollers still reads inconsistently because they do, in fact, allow the bearers to press into them so that the actual height of the roller ends up lower than the height of the bearers. I’ve given up and will have to get the rollers covered again, because the softer blue rubber has been nothing but trouble.

                             

                            ________________

                            Jason Dewinetz

                            Greenboathouse Press

                            www.greenboathouse.com

                             

                             

                             

                            From: PPLetterpress@yahoogroups.com [mailto:PPLetterpress@yahoogroups.com] On Behalf Of Incline Press
                            Sent: February-01-14 1:29 AM
                            To: PPLetterpress@yahoogroups.com
                            Subject: Re: [PPLetterpress] polymer versus lead type

                             

                             




                            Soft forme rollers? You must be joking!

                            This might sound like a problem in theory Kevin, but it never has been in practise. I’d be amused to hear actual occurences of the other experience.


                            Graham Moss
                            Incline Press
                            36 Bow Street
                            Oldham OL1 1SJ  England

                            http://www.inclinepress.com
                            news blog: http://www.inclinepress.wordpress.com






                            But then bearers, as I understand them (in that the form rollers run on them, not the trucks, which run on the rails) won’t have much effect if the form roller is soft. The bearer will sink into the rollers but will not substantially raise the rollers overall, any more than the plunger on a numbering machine would.
                             
                            -Kevin Martin



                          • Jason Dewinetz
                            Gerald, not sure if your comments were directed towards the description of my rollers, but my frustration comes from exactly your point. I sent the cores off
                            Message 13 of 28 , Feb 1, 2014
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                              Gerald, not sure if your comments were directed towards the description of my rollers, but my frustration comes from exactly your point. I sent the cores off to Fritz and he sent them off where he sends them off, and when I received them and voiced concern, a third (replacement) was shipped, still with the softer rubber, and the assurance that I had the right stuff. As I say, I’ve been wrestling with them ever since, and so will have to cut my losses and have them done again. Thank you for mentioning RotaDyne, which is who I’ll contact to get them stripped and covered yet again.

                               

                              Does anyone else out there have an SP-25? I’d love to hear if anyone with rollers this long has had similar issues, and/or if a stiffer rubber (black rather than blue) rectifies the problem I described.

                               

                              Jason

                               

                               

                              From: PPLetterpress@yahoogroups.com [mailto:PPLetterpress@yahoogroups.com] On Behalf Of Gerald Lange
                              Sent: February-01-14 11:03 AM
                              To: PPLetterpress@yahoogroups.com
                              Subject: Re: [PPLetterpress] polymer versus lead type

                               

                               

                              I notice there is a tendency to buy rollers on the cheap. Not sure why since the more expensive rollers aren't all that much more expensive. Especially considering what folks charge for their printed work.

                              The roller manufacturer that Vandercook was using, at least toward the end, was Ideal, now RotaDyne (they have several locations). They are listed in the Links section here. RotaDyne has the original Vandercook specs. I use them and trust them

                              Rollers do need to be slightly harder for printing with photopolymer. Ask for 25. There are a number of reasons for this. There is no mystery and voodoo (though one might thinks so reading all the superstitions and opinions being bandied about), there is a lot of good and accurate information out there and I am not referring to the maelstrom that is the internet.

                              If your press is true and set up properly, and you use quality bases and plates with correct makeready and presswork, there will be no tears, no frustration. With the prices that Vandercooks demand these days it is absolutely curious why folks pinch money on accessories, tools, etc.

                              Gerald
                              http://BielerPressxi.blogspot


                              On 2/1/14 9:43 AM, Jason Dewinetz wrote:

                               

                              Graham, I’ve had issues along the lines of what Kevin’s mentioned. I have an SP-25 Power, which has, obviously, 25-inch rollers. I had them re-covered a year or two ago, and they arrived with the softer (blue) rubber. I’ve had trouble with them from the day they arrived, as the rubber is much softer than the stiffer black covering I have on the rollers for my 15-21. The main issue is that the weight of the rider-rollers causes the middle of the rubber rollers to sag. When I use my roller gauge to set the rollers, there is a very significant drop in the middle third of the rollers, to the extent that 6-inches in from each end I get no ink on the gauge, while in the middle I get more than 1/8-inch. I’ve attempted to use three 12pt type-high rules on either side of the sheet as roller bearers, which definitely helps, but the rollers still reads inconsistently because they do, in fact, allow the bearers to press into them so that the actual height of the roller ends up lower than the height of the bearers. I’ve given up and will have to get the rollers covered again, because the softer blue rubber has been nothing but trouble.

                               

                              ________________

                              Jason Dewinetz

                              Greenboathouse Press

                              www.greenboathouse.com

                               

                               

                               

                              From: PPLetterpress@yahoogroups.com [mailto:PPLetterpress@yahoogroups.com] On Behalf Of Incline Press
                              Sent: February-01-14 1:29 AM
                              To: PPLetterpress@yahoogroups.com
                              Subject: Re: [PPLetterpress] polymer versus lead type

                               

                               




                              Soft forme rollers? You must be joking!

                              This might sound like a problem in theory Kevin, but it never has been in practise. I’d be amused to hear actual occurences of the other experience.


                              Graham Moss
                              Incline Press
                              36 Bow Street
                              Oldham OL1 1SJ  England

                              http://www.inclinepress.com
                              news blog: http://www.inclinepress.wordpress.com






                              But then bearers, as I understand them (in that the form rollers run on them, not the trucks, which run on the rails) won’t have much effect if the form roller is soft. The bearer will sink into the rollers but will not substantially raise the rollers overall, any more than the plunger on a numbering machine would.
                               
                              -Kevin Martin



                               

                            • Gerald Lange
                              Jason I knew a fellow, Norman Fritberg (sp?), who picked up a couple of SP25s from a calendar printer/publisher that went down in St Paul. Norm did beyond
                              Message 14 of 28 , Feb 1, 2014
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                                Jason

                                I knew a fellow, Norman Fritberg (sp?), who picked up a couple of SP25s from a calendar printer/publisher that went down in St Paul. Norm did beyond excellent work. I doubt Vandercook would have made a proof press of that width if rollers would have been inherently iffy of that length. I'd have RotaDyne rewind them and have them check the cores to make sure that they are the correct thickness and haven't been damaged or re-cored so often they are scarred or worn down. I know what you mean, I bought a couple of extra cores for an SP20 a long while back and one of the cores, though sold as new, had been re-cored to the point it looked brutalized. Problem is, so many printers today really don't know what to ask for and shop around only for the least expensive. They get less than what they paid for.

                                If you are using photopolymer, yes, a bit harder roller is best. That is to say a new roller with a higher hardness rating (25) than normally recommended is better, not just a harder roller that has aged. At 50 degrees they will no longer "split" the ink. I know a fellow who claimed his twenty year old rollers were just fine because he "took care of them." Then again there was no evidential record of anything that was ever printed with them.

                                It will work out for you. A durometer will keep you on track, just don't get too freaked out by it, age, knowledge of usage and environmental conditions are pretty good indicators of when to start checkiing with it.

                                Gerald


                                On 2/1/14 6:56 PM, Jason Dewinetz wrote:  

                                Gerald, not sure if your comments were directed towards the description of my rollers, but my frustration comes from exactly your point. I sent the cores off to Fritz and he sent them off where he sends them off, and when I received them and voiced concern, a third (replacement) was shipped, still with the softer rubber, and the assurance that I had the right stuff. As I say, I’ve been wrestling with them ever since, and so will have to cut my losses and have them done again. Thank you for mentioning RotaDyne, which is who I’ll contact to get them stripped and covered yet again.

                                 

                                Does anyone else out there have an SP-25? I’d love to hear if anyone with rollers this long has had similar issues, and/or if a stiffer rubber (black rather than blue) rectifies the problem I described.

                                 

                                Jason

                                 

                                 

                                From: PPLetterpress@yahoogroups.com [mailto:PPLetterpress@yahoogroups.com] On Behalf Of Gerald Lange
                                Sent: February-01-14 11:03 AM
                                To: PPLetterpress@yahoogroups.com
                                Subject: Re: [PPLetterpress] polymer versus lead type

                                 

                                 

                                I notice there is a tendency to buy rollers on the cheap. Not sure why since the more expensive rollers aren't all that much more expensive. Especially considering what folks charge for their printed work.

                                The roller manufacturer that Vandercook was using, at least toward the end, was Ideal, now RotaDyne (they have several locations). They are listed in the Links section here. RotaDyne has the original Vandercook specs. I use them and trust them

                                Rollers do need to be slightly harder for printing with photopolymer. Ask for 25. There are a number of reasons for this. There is no mystery and voodoo (though one might thinks so reading all the superstitions and opinions being bandied about), there is a lot of good and accurate information out there and I am not referring to the maelstrom that is the internet.

                                If your press is true and set up properly, and you use quality bases and plates with correct makeready and presswork, there will be no tears, no frustration. With the prices that Vandercooks demand these days it is absolutely curious why folks pinch money on accessories, tools, etc.

                                Gerald
                                http://BielerPressxi.blogspot


                                On 2/1/14 9:43 AM, Jason Dewinetz wrote:

                                 

                                Graham, I’ve had issues along the lines of what Kevin’s mentioned. I have an SP-25 Power, which has, obviously, 25-inch rollers. I had them re-covered a year or two ago, and they arrived with the softer (blue) rubber. I’ve had trouble with them from the day they arrived, as the rubber is much softer than the stiffer black covering I have on the rollers for my 15-21. The main issue is that the weight of the rider-rollers causes the middle of the rubber rollers to sag. When I use my roller gauge to set the rollers, there is a very significant drop in the middle third of the rollers, to the extent that 6-inches in from each end I get no ink on the gauge, while in the middle I get more than 1/8-inch. I’ve attempted to use three 12pt type-high rules on either side of the sheet as roller bearers, which definitely helps, but the rollers still reads inconsistently because they do, in fact, allow the bearers to press into them so that the actual height of the roller ends up lower than the height of the bearers. I’ve given up and will have to get the rollers covered again, because the softer blue rubber has been nothing but trouble.

                                 

                                ________________

                                Jason Dewinetz

                                Greenboathouse Press

                                www.greenboathouse.com

                                 

                                 

                                 

                                From: PPLetterpress@yahoogroups.com [mailto:PPLetterpress@yahoogroups.com] On Behalf Of Incline Press
                                Sent: February-01-14 1:29 AM
                                To: PPLetterpress@yahoogroups.com
                                Subject: Re: [PPLetterpress] polymer versus lead type

                                 

                                 




                                Soft forme rollers? You must be joking!

                                This might sound like a problem in theory Kevin, but it never has been in practise. I’d be amused to hear actual occurences of the other experience.


                                Graham Moss
                                Incline Press
                                36 Bow Street
                                Oldham OL1 1SJ  England

                                http://www.inclinepress.com
                                news blog: http://www.inclinepress.wordpress.com






                                But then bearers, as I understand them (in that the form rollers run on them, not the trucks, which run on the rails) won’t have much effect if the form roller is soft. The bearer will sink into the rollers but will not substantially raise the rollers overall, any more than the plunger on a numbering machine would.
                                 
                                -Kevin Martin



                                 


                              • Kevin Martin
                                Gerald, Perhaps I don t quite understand the terminology or the re-coring process... My understanding is that the core is the steel rod that runs down the
                                Message 15 of 28 , Feb 2, 2014
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                                  Gerald,
                                  Perhaps I don't quite understand the terminology or the re-coring process... My understanding is that the "core" is the steel rod that runs down the center of the roller, and that recovering the roller involves cutting off the old rubber to leave the core bare. What process would produce scarring or wear of the core?

                                  Jason,
                                  It should be possible to calculate, based on the core length and diameter, and the weight of the oscillator and/or riders, how much sag there should be in the center of the rollers. As an experiment, did you try setting the rollers without the added weight of the oscillator and riders? Could it just be that the rollers are a larger diameter in the center?

                                  -Kevin Martin
                                  the Papertrail Handmade Paper & Book Arts
                                  New Dundee, Ontario
                                  519-884-7123
                                  www.papertrail.ca

                                  -----Original Message-----
                                  From: PPLetterpress@yahoogroups.com [mailto:PPLetterpress@yahoogroups.com] On Behalf Of Gerald Lange

                                  [...] check the cores to make sure that they are the correct thickness and haven't been damaged or re-cored so often they are scarred or worn down.[...]
                                • Jason Dewinetz
                                  Hi Kevin, Yep, I tried that, and they re fine without the rider rollers resting on them: I get a consistent ink reading on the gauge all the way across the
                                  Message 16 of 28 , Feb 2, 2014
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                                    Hi Kevin,

                                     

                                    Yep, I tried that, and they’re fine without the rider rollers resting on them: I get a consistent ink reading on the gauge all the way across the roller. As soon as I set the rider rollers down, that changes. I also took readings on the rubber rollers with a digital calliper, and they seem to be consistent in diameter.

                                     

                                    I did everything I could to discover what was causing the problem, but with other variables accounted for, everything points to the softness of the rubber.

                                     

                                    Jason

                                     

                                     

                                    From: PPLetterpress@yahoogroups.com [mailto:PPLetterpress@yahoogroups.com] On Behalf Of Kevin Martin
                                    Sent: February-02-14 6:32 AM
                                    To: PPLetterpress@yahoogroups.com
                                    Subject: RE: [PPLetterpress] polymer versus lead type

                                     

                                     

                                    Gerald,
                                    Perhaps I don't quite understand the terminology or the re-coring process... My understanding is that the "core" is the steel rod that runs down the center of the roller, and that recovering the roller involves cutting off the old rubber to leave the core bare. What process would produce scarring or wear of the core?

                                    Jason,
                                    It should be possible to calculate, based on the core length and diameter, and the weight of the oscillator and/or riders, how much sag there should be in the center of the rollers. As an experiment, did you try setting the rollers without the added weight of the oscillator and riders? Could it just be that the rollers are a larger diameter in the center?

                                    -Kevin Martin
                                    the Papertrail Handmade Paper & Book Arts
                                    New Dundee, Ontario
                                    519-884-7123
                                    www.papertrail.ca

                                    -----Original Message-----
                                    From: PPLetterpress@yahoogroups.com [mailto:PPLetterpress@yahoogroups.com] On Behalf Of Gerald Lange

                                    [...] check the cores to make sure that they are the correct thickness and haven't been damaged or re-cored so often they are scarred or worn down.[...]

                                  • bielerpr
                                    Kevin Sorry if the terminology is confusing. Be re-coring here I meant altering the surface of the core itself (with a rough cut in a lathe) in the process of
                                    Message 17 of 28 , Feb 2, 2014
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                                      Kevin


                                      Sorry if the terminology is confusing. Be re-coring here I meant altering the surface of the core itself (with a rough cut in a lathe) in the process of rewinding (prior to). 


                                      Gerald

                                    • Kevin Martin
                                      As I understand it, then, the issue is that in stripping the old covering and prepping for the new, some metal is removed from the core each time. One would
                                      Message 18 of 28 , Feb 2, 2014
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                                        As I understand it, then, the issue is that in stripping the old covering and prepping for the new, some metal is removed from the core each time. One would hope that a person recovering a roller would notice that the core is already roughened and not do it again, but then if the old covering is well adhered to the metal, cleaning it all off without removing metal could be a problem.

                                        -Kevin Martin
                                        the Papertrail Handmade Paper & Book Arts
                                        New Dundee, Ontario
                                        519-884-7123
                                        www.papertrail.ca




                                        -----Original Message-----
                                        From: PPLetterpress@yahoogroups.com [mailto:PPLetterpress@yahoogroups.com] On Behalf Of Bieler@...

                                        Sorry if the terminology is confusing. Be re-coring here I meant altering the surface of the core itself (with a rough cut in a lathe) in the process of rewinding (prior to).
                                      • Kevin Martin
                                        Jason, I don t really feel that the rubber roller covering contributes anything significant to the lengthwise bending of the roller because steel in the core
                                        Message 19 of 28 , Feb 2, 2014
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                                          Jason,
                                          I don't really feel that the rubber roller covering contributes anything significant to the lengthwise bending of the roller because steel in the core is orders of magnitude stiffer than the rubber. It may indeed be, as Gerald has suggested, that the cores have lost enough of their diameter to sag under the weight of the other rollers. If this is the case, recovering them would only worsen matters.

                                          I recently acquired a Challenge MA15 and I would find it interesting to see if I can observe this sag effect. It may not be noticeable using the inking gauge but I have a dial indicator that reads 0.0001" that might notice some sag.

                                          By the way, I'm not sure I would want to rely on the colour of the rubber as an indicator of hardness.

                                          -Kevin Martin
                                          the Papertrail Handmade Paper & Book Arts
                                          New Dundee, Ontario
                                          519-884-7123
                                          www.papertrail.ca

                                          -----Original Message-----
                                          From: PPLetterpress@yahoogroups.com [mailto:PPLetterpress@yahoogroups.com] On Behalf Of Jason Dewinetz

                                          Yep, I tried that, and they're fine without the rider rollers resting on them: I get a consistent ink reading on the gauge all the way across the roller. As soon as I set the rider rollers down, that changes. I also took readings on the rubber rollers with a digital calliper, and they seem to be consistent in diameter.

                                          I did everything I could to discover what was! causing the problem, but with other variables accounted for, everything points to the softness of the rubber.
                                        • kringds
                                          Eric, What are ornamental bearers? Over the years, in my quest for perfect inking on my C&P, I have gotten the recommendation of bearers from some. Others say
                                          Message 20 of 28 , Feb 2, 2014
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                                            Eric,


                                            What are ornamental bearers? Over the years, in my quest for perfect inking on my C&P, I have gotten the recommendation of bearers from some. Others say as you do that they do not do much for roller height.
                                            In the past I did some test using strips of polymer as makeshift bearers and did not see any beneficial results. I think this is because of the softness of the rollers. For a bearer to lift and carry the rollers then they have to be pretty heavy on the bearer. If the bearer is type high then they would be hitting the form to the same degree.

                                            However, if I had adjustable bearers that could be increased incrementally above type high, possibly with tape, then I should be able to adjust them to a working height.

                                            I am sure this sounds idiotic to many, especially people that have presses that are finer than C&P NS. But to me it sounds like it would be worth a shot. My remaining question is if I need some type of texture (or ornament) on the bearers to keep the rollers from slipping. If that is the case then I would need to adjust them from the back which would be more trouble, obviously.



                                            ---In PPLetterpress@yahoogroups.com, <Megalonyx@...> wrote:

                                            Roller bearers don't do much in regard to roller HEIGHT setting. They can have a real effect on roller motion, which is a serious problem with photopolymer, magnified by differences in roller and truck diameter on a platen, causing slur. But they don't do much at all to lift soft rollers. When used on a proof press with automatic inking, I think the effect of bearers is more to equalize impression, which is why it was standard practice when pulling repro proofs. The reason Kelsey sold so many sets of wide roller bearers is because they had one style of roller truck that was not keyed to the shaft and just turned loosely: crazy slur.

                                            When I started printing it was just metal type and plates and the odd linoleum cut, all easily inked using my Dad's and my teacher's method, which was to inspect the image left on the roller after it passes the form, look at the print, and then adjust the Morgan truck accordingly. This did not work when I added photopolymer plates to the process, in large part because the harder contact wanted by a metal form was too much for photopolymer and the over expansion of Morgans in compensation lead to eccentricity, which causes the wandering ink densities that have been questioned so often online. Eventually I realized it was a more complicated relationship between roller and plate surface, and truck and track, because the photopolymer plate does not grab the roller as a metal form does, it slips; some pre-photopolymer authors tell you to keep the trucks smaller than the roller so the form will grab the roller and make it turn. Do that with photopolymer and all you will get is ghosting, slurred leading and trailing edges and ink wiped onto the edge of the plate. With very hard rollers I found that using ornamental bearers grabbed the roller and got it turning at speed before it hit the form: with photopolymer the rollers must roll over the entire form at even speed, no slippage anywhere. That's easier on a Vandercook with geared form rollers than it is on most platens.

                                            Eric Holub, SF



                                            ---In PPLetterpress@yahoogroups.com, <kwhalen.incline@...> wrote:

                                            Re: [PPLetterpress] polymer versus lead type Type high bearers pretty much take care of this.

                                            You’ll figure out yourself how fussy you are happy with being, as soon as you gain experience with the printed images.


                                            Graham Moss
                                            Incline Press
                                            36 Bow Street
                                            Oldham OL1 1SJ  England

                                            http://www.inclinepress.com
                                            news blog: http://www.inclinepress.wordpress.com



                                            I have read many times that with polymer plates you have to be much more precise in the setting of the roller heights (on a platen press at least) than with lead type. Why is this so? Is it because the edges of the letterforms are sharper on lead, so that you can hit them with the rollers a little harder without showing any slur? Or does it have to do with the material? Does the ink transfer easier to lead than to polymer?
                                            thank you,
                                            bryan kring










                                          • Scott Rubel
                                            I don t think any of this talk is out of line. That s what this Yahoo group is for. I never even thought of using bearers that were metal instead of polymer. I
                                            Message 21 of 28 , Feb 2, 2014
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                                              I don't think any of this talk is out of line. That's what this Yahoo group is for.

                                              I never even thought of using bearers that were metal instead of polymer. I can see that metal would give traction, and that an ornamental rule would give even more (like new tires on your auto).

                                              --Scott


                                              On Feb 2, 2014, at 6:50 PM, <bryan@...> wrote:

                                              Eric, 

                                              What are ornamental bearers? Over the years, in my quest for perfect inking on my C&P, I have gotten the recommendation of bearers from some. Others say as you do that they do not do much for roller height. 

                                              In the past I did some test using strips of polymer as makeshift bearers and did not see any beneficial results. I think this is because of the softness of the rollers. For a bearer to lift and carry the rollers then they have to be pretty heavy on the bearer. If the bearer is type high then they would be hitting the form to the same degree. 

                                              However, if I had adjustable bearers that could be increased incrementally above type high, possibly with tape, then I should be able to adjust them to a working height.

                                              I am sure this sounds idiotic to many, especially people that have presses that are finer than C&P NS. But to me it sounds like it would be worth a shot. My remaining question is if I need some type of texture (or ornament) on the bearers to keep the rollers from slipping. If that is the case then I would need to adjust them from the back which would be more trouble, obviously.



                                              ---In PPLetterpress@yahoogroups.com, <Megalonyx@...> wrote:

                                              Roller bearers don't do much in regard to roller HEIGHT setting. They can have a real effect on roller motion, which is a serious problem with photopolymer, magnified by differences in roller and truck diameter on a platen, causing slur. But they don't do much at all to lift soft rollers. When used on a proof press with automatic inking, I think the effect of bearers is more to equalize impression, which is why it was standard practice when pulling repro proofs. The reason Kelsey sold so many sets of wide roller bearers is because they had one style of roller truck that was not keyed to the shaft and just turned loosely: crazy slur.

                                              When I started printing it was just metal type and plates and the odd linoleum cut, all easily inked using my Dad's and my teacher's method, which was to inspect the image left on the roller after it passes the form, look at the print, and then adjust the Morgan truck accordingly. This did not work when I added photopolymer plates to the process, in large part because the harder contact wanted by a metal form was too much for photopolymer and the over expansion of Morgans in compensation lead to eccentricity, which causes the wandering ink densities that have been questioned so often online. Eventually I realized it was a more complicated relationship between roller and plate surface, and truck and track, because the photopolymer plate does not grab the roller as a metal form does, it slips; some pre-photopolymer authors tell you to keep the trucks smaller than the roller so the form will grab the roller and make it turn. Do that with photopolymer and all you will get is ghosting, slurred leading and trailing edges and ink wiped onto the edge of the plate. With very hard rollers I found that using ornamental bearers grabbed the roller and got it turning at speed before it hit the form: with photopolymer the rollers must roll over the entire form at even speed, no slippage anywhere. That's easier on a Vandercook with geared form rollers than it is on most platens.

                                              Eric Holub, SF



                                              ---In PPLetterpress@yahoogroups.com, <kwhalen.incline@...> wrote:

                                              Type high bearers pretty much take care of this. 

                                              You’ll figure out yourself how fussy you are happy with being, as soon as you gain experience with the printed images.


                                              Graham Moss
                                              Incline Press
                                              36 Bow Street
                                              Oldham OL1 1SJ  England

                                              http://www.inclinepress.com
                                              news blog: http://www.inclinepress.wordpress.com



                                              I have read many times that with polymer plates you have to be much more precise in the setting of the roller heights (on a platen press at least) than with lead type. Why is this so? Is it because the edges of the letterforms are sharper on lead, so that you can hit them with the rollers a little harder without showing any slur? Or does it have to do with the material? Does the ink transfer easier to lead than to polymer?
                                              thank you,
                                              bryan kring













                                            • Jason Dewinetz
                                              Hey Kevin, I have to admit, it never occurred to me that the cores could actually sag, given that theyÆre what looks to be ╛ö steel rods. Even if ground
                                              Message 22 of 28 , Feb 2, 2014
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                                                Hey Kevin,

                                                 

                                                I have to admit, it never occurred to me that the cores could actually sag, given that they’re what looks to be ¾” steel rods. Even if ground again and again during recovering, I find it hard to believe that they’d become weak enough to sag; I just assumed the rubber itself was getting squished under the weight of the riders. Bad cores also seem unlikely because the press itself was in storage for much of its life, so these cores have likely only been recovered a handful of times.

                                                 

                                                The problem is, at this point, I can determine one way or the other (if it’s the rubber or the core itself that’s sagging, or if the rubber is being squished down). The bottom line is that I’m getting nothing but awful results with what I have, so I’ll ship them off to RotaDyne and ask them to give me a report on the condition of the cores themselves once stripped. If they’re no good, I’ll have them make new ones.

                                                 

                                                Jason

                                                 

                                                 

                                                From: PPLetterpress@yahoogroups.com [mailto:PPLetterpress@yahoogroups.com] On Behalf Of Kevin Martin
                                                Sent: February-02-14 1:22 PM
                                                To: PPLetterpress@yahoogroups.com
                                                Subject: RE: [PPLetterpress] polymer versus lead type

                                                 

                                                 

                                                Jason,
                                                I don't really feel that the rubber roller covering contributes anything significant to the lengthwise bending of the roller because steel in the core is orders of magnitude stiffer than the rubber. It may indeed be, as Gerald has suggested, that the cores have lost enough of their diameter to sag under the weight of the other rollers. If this is the case, recovering them would only worsen matters.

                                                I recently acquired a Challenge MA15 and I would find it interesting to see if I can observe this sag effect. It may not be noticeable using the inking gauge but I have a dial indicator that reads 0.0001" that might notice some sag.

                                                By the way, I'm not sure I would want to rely on the colour of the rubber as an indicator of hardness.

                                                -Kevin Martin
                                                the Papertrail Handmade Paper & Book Arts
                                                New Dundee, Ontario
                                                519-884-7123
                                                www.papertrail.ca

                                                -----Original Message-----
                                                From: PPLetterpress@yahoogroups.com [mailto:PPLetterpress@yahoogroups.com] On Behalf Of Jason Dewinetz

                                                Yep, I tried that, and they're fine without the rider rollers resting on them: I get a consistent ink reading on the gauge all the way across the roller. As soon as I set the rider rollers down, that changes. I also took readings on the rubber rollers with a digital calliper, and they seem to be consistent in diameter.

                                                I did everything I could to discover what was! causing the problem, but with other variables accounted for, everything points to the softness of the rubber.

                                              • Kathleen Whalen
                                                Quarter inch bar is not likely to be flexing over 27 or so, inches, unless under pressure - I d first look to the problem as more likely to be in the pressure
                                                Message 23 of 28 , Feb 3, 2014
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                                                  Quarter inch bar is not likely to be flexing over 27 or so, inches, unless
                                                  under pressure - I'd first look to the problem as more likely to be in the
                                                  pressure of the ink distribution system being mal-adjusted. But as I
                                                  remember it, the ink distribution mechanism just works by friction on the
                                                  inking roller - it would be odd indeed in Vandercook didn't get that right
                                                  and no-one noticed it before. Which, on Holmesian principles, takes you to a
                                                  rubber roller that's too soft, eh? Is there a visible flat spot between the
                                                  steel drum and the inking roller? Can the inking roller be raised to suit
                                                  the surface being printed from? Is the diameter of the new roller correct?

                                                  I suppose it could be different in different parts of the world, but here
                                                  the cores are not damaged by rubber removal (old rubber is cut off with a
                                                  knife), and the fix on the core is made by adding a wide and tight spiral of
                                                  string to the core before the rubber goes on and they are vulcanised to
                                                  acquire the Shore number required and then turned in a lathe to the exact
                                                  dimension required.

                                                  It shouldn't be difficult to use the Yellow Pages to arrange a visit to a
                                                  roller manufacturer, and one as close to home as possible is always a good
                                                  idea for any supplier. Rollers are widely used in any number of industrial
                                                  processes, not just for printing machines - those manufacturers I've been to
                                                  have all been happy to show the process, and like the rest of us somewhat
                                                  flattered that someone shows an interest, and it goes a long way in avoiding
                                                  pointless discussion. Another series of fault-lines in the digital world.


                                                  Graham Moss
                                                  Incline Press
                                                  36 Bow Street
                                                  Oldham OL1 1SJ England

                                                  http://www.inclinepress.com
                                                  news blog: http://www.inclinepress.wordpress.com





                                                  On 2/2/14 21:11, "Kevin Martin" <kpmartin@...> wrote:

                                                  > As I understand it, then, the issue is that in stripping the old covering and
                                                  > prepping for the new, some metal is removed from the core each time. One would
                                                  > hope that a person recovering a roller would notice that the core is already
                                                  > roughened and not do it again, but then if the old covering is well adhered to
                                                  > the metal, cleaning it all off without removing metal could be a problem.
                                                • Scott Coutts
                                                  I assume this is the same with etched magnesium or copper?
                                                  Message 24 of 28 , Feb 3, 2014
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                                                    I assume this is the same with etched magnesium or copper?

                                                    On 01/02/2014 4:52 am, "Scott Rubel" <scott@...> wrote:
                                                     

                                                    It's because the polymer washes out and leaves a bevel from the surface to the base. If the rollers are too low, they ink the "sides" of the type. With lead, the sides are almost at right angles and maladjusted rollers will not so much ink the sides. Lead type always looks cleaner no matter what you do.


                                                    --Scott

                                                    On Jan 31, 2014, at 9:45 AM, bryan@... wrote:



                                                    I have read many times that with polymer plates you have to be much more precise in the setting of the roller heights (on a platen press at least) than with lead type. Why is this so? Is it because the edges of the letterforms are sharper on lead, so that you can hit them with the rollers a little harder without showing any slur? Or does it have to do with the material? Does the ink transfer easier to lead than to polymer?

                                                    thank you,
                                                    bryan kring



                                                  • Kevin Martin
                                                    I just ran some numbers measured from my Challenge MA15 through a beam bending formula: Steel core diameter 5/8 , length 20 , oscillator weight 13 pounds (half
                                                    Message 25 of 28 , Feb 3, 2014
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                                                      I just ran some numbers measured from my Challenge MA15 through a beam bending formula: Steel core diameter 5/8", length 20", oscillator weight 13 pounds (half on each form roller, evenly distributed along the length) and the calculation indicated that the center of the core would deflect by about 0.003". This is in addition to any settling of the core overall on its bearings etc.

                                                      I tried measuring the actual sag on one of my rollers, and although it was tricky to get accurate results, I found that the center of the roller sags about 0.0013" more than the ends do when the oscillator is lowered. The weight of the rider adds about another 0.0004" sag. This is only about 1/3 of what the formula indicates, but as I said, it was difficult to measure.

                                                      The sag is inversely proportional to the fourth power of the core diameter, so if for instance my cores were only 3/8" because of repeated resurfacings, the sag would increase by a factor of 8 to about 0.024" (almost 2 points)!
                                                      -Kevin Martin
                                                      the Papertrail Handmade Paper & Book Arts
                                                      New Dundee, Ontario
                                                      519-884-7123
                                                      www.papertrail.ca

                                                      -----Original Message-----
                                                      From: PPLetterpress@yahoogroups.com [mailto:PPLetterpress@yahoogroups.com] On Behalf Of Jason Dewinetz

                                                      I have to admit, it never occurred to me that the cores could actually sag, given that they're what looks to be ¾" steel rods. Even if ground again and again during recovering, I find it hard to believe that they'd become weak enough to sag; I just assumed the rubber itself was getting squished under the weight of the riders. Bad cores also seem unlikely because the press itself was in storage for much of its life, so these cores have likely only been recovered a handful of times.
                                                    • Jason Dewinetz
                                                      Kevin, youÆre a serious fiend with the formulas & measuring tools! IÆm somewhat relieved to hear that there is a rational explanation for what weÆve been
                                                      Message 26 of 28 , Feb 3, 2014
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                                                        Kevin, you’re a serious fiend with the formulas & measuring tools!

                                                         

                                                        I’m somewhat relieved to hear that there is a rational explanation for what we’ve been talking about, but dismayed to hear that the sag may be unavoidable. As you say, there is potential for this sag to have a significant impact to inking.

                                                         

                                                        The next question, of course, would be: how much impact does the hardness of the rubber have to the sag? Does a softer rubber displace under the weight? If so, does it displace from top to bottom, causing a bulge at the bottom? (Which has always been my assumption…)

                                                         

                                                        The next time I ink up I’m going to lift the oscillator & rider and try a print. Of course this means the rear roller won’t turn until it hits the type, and even then it may slide rather than turn over the forme. It also means, if the rollers make a complete rotation before the bottom of the forme, that the lower forme will get a roller already robbed of its ink.

                                                         

                                                        Perhaps I can rig my oscillator & rider to sit up a bit higher during printing, so that there’s not so much weight on the rollers.

                                                         

                                                        I’m sure to many this all sounds ridiculous, as it would to me if we were talking about my 15-21, as I’ve never had any issue on that press, but this big beast has been very tricky to work with since the day I turned it on, and thus I’m eager to investigate every potential way to improve the inking issue.

                                                         

                                                        By the way, and this should be obvious, impression on the press is perfect. A blind print produces a very even impression on the paper, so it’s clear that my difficulty is with the rollers.

                                                         

                                                        Jason

                                                         

                                                        From: PPLetterpress@yahoogroups.com [mailto:PPLetterpress@yahoogroups.com] On Behalf Of Kevin Martin
                                                        Sent: February-03-14 7:55 PM
                                                        To: PPLetterpress@yahoogroups.com
                                                        Subject: RE: [PPLetterpress] polymer versus lead type

                                                         

                                                         

                                                        I just ran some numbers measured from my Challenge MA15 through a beam bending formula: Steel core diameter 5/8", length 20", oscillator weight 13 pounds (half on each form roller, evenly distributed along the length) and the calculation indicated that the center of the core would deflect by about 0.003". This is in addition to any settling of the core overall on its bearings etc.

                                                        I tried measuring the actual sag on one of my rollers, and although it was tricky to get accurate results, I found that the center of the roller sags about 0.0013" more than the ends do when the oscillator is lowered. The weight of the rider adds about another 0.0004" sag. This is only about 1/3 of what the formula indicates, but as I said, it was difficult to measure.

                                                        The sag is inversely proportional to the fourth power of the core diameter, so if for instance my cores were only 3/8" because of repeated resurfacings, the sag would increase by a factor of 8 to about 0.024" (almost 2 points)!
                                                        -Kevin Martin
                                                        the Papertrail Handmade Paper & Book Arts
                                                        New Dundee, Ontario
                                                        519-884-7123
                                                        www.papertrail.ca

                                                        -----Original Message-----
                                                        From: PPLetterpress@yahoogroups.com [mailto:PPLetterpress@yahoogroups.com] On Behalf Of Jason Dewinetz

                                                        I have to admit, it never occurred to me that the cores could actually sag, given that they're what looks to be ¾" steel rods. Even if ground again and again during recovering, I find it hard to believe that they'd become weak enough to sag; I just assumed the rubber itself was getting squished under the weight of the riders. Bad cores also seem unlikely because the press itself was in storage for much of its life, so these cores have likely only been recovered a handful of times.

                                                      • Kathleen Whalen
                                                        Brilliant work Kevin! I think Jason, that this suggests to me that you would be better using the width of the bed rather than the length of the bed when
                                                        Message 27 of 28 , Feb 4, 2014
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                                                          Re: [PPLetterpress] polymer versus lead type Brilliant work Kevin!

                                                          I think Jason, that this suggests to me that you would be better using the width of the bed rather than the length of the bed when printing a broadside.
                                                          The pressure will still be there, but the support along the length of the roller should give a better printed result.

                                                          Worth a try.


                                                          Graham Moss
                                                          Incline Press
                                                          36 Bow Street
                                                          Oldham OL1 1SJ  England

                                                          http://www.inclinepress.com
                                                          news blog: http://www.inclinepress.wordpress.com





                                                        • Kevin Martin
                                                          How important this issue is depends on how finely you have set the rollers. A 1/8 ink stripe on the lollipop-style gauge indicates that the roller will be
                                                          Message 28 of 28 , Feb 4, 2014
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                                                            How important this issue is depends on how finely you have set the rollers. A 1/8" ink stripe on the lollipop-style gauge indicates that the roller will be compressed by about 0.008" over the type. A 1/16" stripe would be a quarter of that, about 0.002", at which point the roller sag would be on the same scale.

                                                            In any case, flexing in other parts of the mechanism (the bearings, etc.) indicate to me that the roller height should be set with the oscillator and riders down if you want it finely set.

                                                            I was going to suggest trying a print with the extra rollers up (in which case you would want to adjust roller height in the same state), but as you say there are downsides to this.

                                                            The rubber compound probably also sags under its own weight, but I don't have a good feel for how much sag there would be. Probably less that the sag from the rider weight, mostly because the rubber weighs less and there are no long spans involved. I would expect it to be uniform across the width of the roller, though, so the effect would be invisible. I suppose the weight of the rider and oscillator would deform the rubber a bit more but that again would be uniform across the width of the roller, and that may be some of what I described above as "flexing in other parts of the mechanism."
                                                            -Kevin Martin
                                                            the Papertrail Handmade Paper & Book Arts
                                                            New Dundee, Ontario
                                                            519-884-7123
                                                            www.papertrail.ca



                                                            -----Original Message-----
                                                            From: PPLetterpress@yahoogroups.com [mailto:PPLetterpress@yahoogroups.com] On Behalf Of Jason Dewinetz
                                                            Sent: Tuesday, February 04, 2014 12:41 AM
                                                            To: PPLetterpress@yahoogroups.com
                                                            Subject: RE: [PPLetterpress] polymer versus lead type

                                                            [...]
                                                            The next question, of course, would be: how much impact does the hardness of the rubber have to the sag? Does a softer rubber displace under the weight? If so, does it displace from top to bottom, causing a bulge at the bottom? (Which has always been my assumption...)

                                                            The next time I ink up I'm going to lift the oscillator & rider and try a print. Of course this means the rear roller won't turn until it hits the type, and even then it may slide rather than turn over the forme. It also means, if the rollers make a complete rotation before the bottom of the forme, that the lower forme will get a roller already robbed of its ink.
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