## Re: [PPLetterpress] Re: PSI of pressure exerted by platen or flatbedpresses?

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• Smaller platens would be less, I suspect, but a Vandercook could be quite high because the pressure is delivered across the line where the cylinder meets the
Message 1 of 31 , Mar 21, 2010
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Smaller platens would be less, I suspect, but a Vandercook could be
quite high because the pressure is delivered across the line where
the cylinder meets the matter and this line is not wide. For an
extreme example, very hard packing combined with thin stock might
give a pressure line of only .05 inches width (due to compressing the
materials). If the cylinder is, say, 15 inches long and the matter
all black, the total area at any instant would be only .75 in^2. This
means that 500 psi could be reached with only a few hundred pounds of
force supplied by the cylinder. The cylinder plus carriage on my
press weighs upwards of 200 lbs, so this gives 260 psi without even
engaging the bearings!

Russ

On Mar 20, 2010, at 4:31 PM, Yvon wrote:

> Ah, that's good info Peter, thank you. I suspect a Vandercook
> flatbed or smaller platen would likely provide somewhat less
> pressure than 540PSI, it's a number that I can at least use as a
> baseline.
>
> Anybody else have a PSI spec on a proofpress or a platen?
>
>
> --- In PPLetterpress@yahoogroups.com, Peter Fraterdeus <peterf@...>
> wrote:
> >
> > The 10x15 Heidelberg provides 35 tons of "impressional strength"
> > according to the manual IIRC
> >
> > So given approx 130 square inches of useable form, this is about 540
> > psi. over a full solid form (not recommend !!)
> >
> > 35 tons=~ 70000lb/130sqin=~540lb/sqin
> >
> > The Windmill is, of course, known for its exceptional
> engineering, so
> > this clearly represents the high end perhaps even by an order of
> > magnitude beyond, say, a small C&P...
> >
> > A smaller form will of course raise that number substantially! So
> even
> > a small press will pack quite a punch on a single line of type!
> >
> > Just speculating here of course. I'm no engineer!
> >
> > P
> >
> > Slowprint.com / Semiotx.com
> > google voice 1 563 223 8231
> > peterf@...
> >
> > From iPhone plz excuse brevity!
> >
> > On Mar 20, 2010, at 10:01 AM, leorawest@... wrote:
> >
> > > I don't have the PSI info per se, but it is enough to crush human
> > > bone, specifically fingers -- perhaps you could research this in
> > > reverse.
> > >
> > > Leora
> > > Copper Willow
> > >
> >
>
>
>
• Thanks for this Fritz. A clever system for smaller forms to be sure. Indeed I can source aluminum bar stock in my area and will keep looking for that
Message 31 of 31 , Mar 27, 2010
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Thanks for this Fritz. A clever system for smaller forms to be sure. Indeed I can source aluminum bar stock in my area and will keep looking for that checkbook to complete the deed :)

--- In PPLetterpress@yahoogroups.com, "Fritz Klinke" <nagraph@...> wrote:
>
> As I looked at these further, I've changed my thinking a little. I think what they were using was standard widths of aluminum bar stock in different widths that they had Blanchard ground down to .850, which is what the bare metal measures, then cut them to length on a saw. For standard measures, like column widths of say 18, or 20 picas, then numerous blanks could be cut the same length. And these can be stripped and used over. The aluminum gives the strength needed for deep impression work if not used with metal type. There is evidence on the ends of the longer ones of these that they employed a quick release clamping system to lock these up in the chase. Typically, a chase would be made up for the style of check being printed, like 3-up business checks with a stub, and then job after job was run with the same set up but just changing the imprint lines and the logos. In the Deluxe Check videos of their operation, a pressman was getting the next job ready with a second or third chase while the current job printed. The V-50X models they used had preset cut off attachments so the press would shut down after a preset number of sheets had been printed, thus freeing up the pressman to work at his stone on the next job.
>
> I would think that these could be made up by about anyone with access to a machine shop that has Blanchard grinding available, and a check book, and McMaster Carr sells the raw aluminum bar stock. A saw, either a printer's saw, or a band saw with a metal cutting blade, could be used in the print shop to cut these to length.
>
> Fritz
>
> ----- Original Message -----
> To: PPLetterpress@yahoogroups.com
> Sent: Thursday, March 25, 2010 6:58 PM
> Subject: [PPLetterpress] Re: PSI of pressure exerted by platen or flatbed presses?
>
>
>
> I love it, where do I find some of these?
>
> --- In PPLetterpress@yahoogroups.com, "Fritz Klinke" <nagraph@> wrote:
> >
> > Something about this discussion was nagging me to think that this is old hat stuff as far as photopolymer goes, and the answer was sitting in a galley about 25 feet from my desk. The check printers used photopolymer extensively in the latter years of check printing when almost every check printer used Miehle Verticals for imprinting. They offered stock logos plus custom logos for an up charge. These were mixed in with machine set type. The ones in this link:
> >
> > http://www.flickr.com/photos/53177163@N00/4461088925/sizes/l/
> >
> > came out of a Harland plant and I've had them about15 years--this stuff was stock and trade in commercial plants 20 and 25 years ago. They used steel backed photopolymer mounted to what I think is Blanchard ground magnesium using double faced tape. Magnesium, with appropriate safe guards, can be easily cut on a printer's saw so that these blocks can be cut accurately to point and pica sizes for mixing with metal type. The ones in my picture all mic out at .918. It has already been done and abandoned in the commercial field of letterpress.
> >
> > fritz
> >
> > From: Half Press
> > To: PPLetterpress@yahoogroups.com
> > Sent: Wednesday, March 24, 2010 4:37 PM
> > Subject: Re: [PPLetterpress] Re: PSI of pressure exerted by platen or flatbed presses?
> >
> >
> >
> > Yes. It does work. The principle is, think it up for yourself. Wood does it. Little metal pieces will do it better. I think some folks out there who produce bases, could just come up with a XXI century solution and go business with it.
> >
> > I do have a very good aluminum base I purchased from NA Graphics. That base is awesome and the price is good. Call him now for good bases.
> >
> >
> >
> >
> > I said something about finding stuff over in Germany, simply because they are beyond advanced and if you are lucky, you may find a lot of stuff that you wouldn't find anywhere else. I found brand new brass rules. I was/am jumping in joy!
> >
> >
> >
> >
> > Looking at your link to Interrobang that guy is absolutely correct. He even has superb gauges from the good old 1920s. And lots of metal bases. I found a tone of those on auctions; so many I could have a 9x12 inches base area and of course I just bought it.
> >
> >
> >
> >
> > Keep your eyes open on the auctions and if you can, don't overpay for stuff.
> >
> >
> >
> >
> > *Interrobang showed here sometime ago a booklet with a script font . A font he "revived" in few hours "in one evening", as he put it.
> >
> >
> > --- On Wed, 3/24/10, Yvon <yal@> wrote:
> >
> >
> > From: Yvon <yal@>
> > Subject: [PPLetterpress] Re: PSI of pressure exerted by platen or flatbed presses?
> > To: PPLetterpress@yahoogroups.com
> > Date: Wednesday, March 24, 2010, 6:53 PM
> >
> >
> >
> > Thanks for your input on the pressure related issues halfpress.
> > I especially like your suggestion of combining a few strips of material for a small printing area.
> > In a similar concept, I saw an interesting set of photos on Flickr where the fellow is remounting old copper cuts on wood or metal furniture, I suspect one might be able to mount small polymer logos in a similar fashion that would enable one to possibly combine polymer with lead for short runs:
> > http://www.flickr com/photos/ interrobang918/ sets/72157614585 493594/
> >
> > --- In PPLetterpress@ yahoogroups. com, "half.press" <half.press@ ...> wrote:
> > >
> > >
> > >
> > > --- In PPLetterpress@ yahoogroups. com, "Yvon" <yal@> wrote:
> > > >
> > > > Can anyone tell me just how many pounds of pressure are exerted while printing on C&P platens or Vandercook and similar flatbed proof presses?
> > > >
> > > > Until I'm ready to invest in a large Boxcar or Elum aluminum base, I had a few materials that are less brittle than plexi/acrylic suggested to me, ie: UHMW, HMPE, HPPE or even PVC, all of which I am hoping would cope with the downward pressure exerted during an impression, and also would be easier/considerably cheaper to cut/machine than metal.
> > > >
> > > > Any suggestions on materials/process would be most welcome.
> > > >
> > > ****
> > >
> > > Hello folks,
> > >
> > > Not speaking much though but it is not because I would not like to give you my recipes...
> > >
> > > How much PSI pressure does you press produce? Well, that is piece of information that will not help you at all. Are you using calculators? If you lock a small plate or form on a platen press, whatever one, it will seem like the press is producing more pressure. That is because the smaller the plate the lesser resistance and less pressure expanding across your platen. When you have a bigger form or plate there will be more resistance and resulting in more work on getting it right.
> > > On cylinders, the strip that prints is smaller that what would be on a platen, where the form is "pressed" equally across on a strip; that gives you a huge bite which is a whole lot more PSIs that you could calculator extremely happy...
> > >
> > > About using a mix of polymer and type, it does work. Just make sure all type-high and, if you see any difference in the print, between what is type and what is polymer (bubbles, blotching etc) that is simple; using a very fine sand paper, dampened with some ink cleaner solution (whatever you use) sand the polymer plate, carefully, to make is less "shiny" or smooth. That will do. Sometimes the smoother the surface of the plate, the worst the print.
> > >
> > > I come across metal aluminum bases on a famous auction site in Germany. Those bases have various sizes, from a simple strip of 12 points up to many sizes , 24, 36, 48 points up to bigger pieces, that combined can produce bigger surfaces. Those are so handy and you can glue you polymer plates to it with easy. You could also use some of your wood furniture as base. If you like that. Just so you know; the aluminum plates are the best invention ever since the press itself ...
> > >
> >
>
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