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Essential and optional features of a lathe

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  • k15n1
    Found some practical information about essential features of a lathe. It s based on the experience of a user who apparently has his choice of lathes so it may
    Message 1 of 10 , May 27, 2014
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      Found some practical information about essential features of a lathe.  It's based on the experience of a user who apparently has his choice of lathes so it may not make sense from a cost perspective.  But if the point is to do the work first, right?  Being cheap and easy to build are secondary to usefullness.  See the excerpt below [1]. 


      Here's my commentary on the "essential" features.


      1. Screwcutting - yes!
      2. Backgear - low speed capability is already part of the design assumptions
      3. Tumble Reverse - no
      4. Provision to fit T slotted cross slide - Cutting T slots would be a challenge without a mill, so this might not be possible.
      5. 2 Morse taper in tailstock - only marginal cost if you're buying an insert [2,4] or buying a reamer [3]
      6. Set-over tailstock for taper turning - can build
      7. Gearing to handle on apron traverse - no, power feed isn't a priority (if I understand this correctly)





      1. http://www.lathes.co.uk/page2.html

      2. http://www.sawmillcreek.org/showthread.php?17423-Home-Made-Tail-Stock-Where-to-find-Morse-Taper-Insert

      3. http://www.mcmaster.com/#morse-taper-socket-reamers/=s5bl6u

      4. http://www.mscdirect.com/browse/tn/Tool-Holding/Morse-Taper-Sleeves-Sockets/Morse-Taper-Sockets?navid=12108514





      Essential Features in a Small Lathe
      Screwcutting
      Backgear
      Tumble Reverse
      Provision to fit T slotted cross slide
      2 Morse taper in tailstock
      Set-over tailstock for taper turning
      Gearing to handle on apron traverse

      Desirable Features in a Small Lathe
      Quick-set or 4-way tool holder
      Gap bed (up to 3.5"/90mm centre height)
      At least 0.5"/13mm hole through spindle
      Dial-thread indicator for screwcutting
      Spindle lock to aid removal of chucks
      Automatic disengage to saddle drive
      Provision to mount collets
      Graduated tailstock barrel

      Non-Essential but Useful Features in a Small Lathe
      Screwcutting gearbox
      Power cross feed
      Clutch to headstock spindle drive
      1" (26mm) or larger hole through spindle
      Coolant equipment
      Graduated handle to leadscrew end
      Availability of lever-action tailstock
      Electronic or mechanical variable-speed drive
    • Philip X. Diaz
      Being cheap and easy to build WOULD be priorities if you are in a developing country and do not readily have access to machine tools! On Tue, May 27, 2014 at
      Message 2 of 10 , May 27, 2014
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        Being cheap and easy to build WOULD be priorities if you are in a developing country and do not readily have access to machine tools!





        On Tue, May 27, 2014 at 7:07 AM, neffk@... [multimachine] <multimachine@yahoogroups.com> wrote:

        Found some practical information about essential features of a lathe.  It's based on the experience of a user who apparently has his choice of lathes so it may not make sense from a cost perspective.  But if the point is to do the work first, right?  Being cheap and easy to build are secondary to usefullness.  See the excerpt below [1]. 


        Here's my commentary on the "essential" features.


        1. Screwcutting - yes!
        2. Backgear - low speed capability is already part of the design assumptions
        3. Tumble Reverse - no
        4. Provision to fit T slotted cross slide - Cutting T slots would be a challenge without a mill, so this might not be possible.
        5. 2 Morse taper in tailstock - only marginal cost if you're buying an insert [2,4] or buying a reamer [3]
        6. Set-over tailstock for taper turning - can build
        7. Gearing to handle on apron traverse - no, power feed isn't a priority (if I understand this correctly)





        1. http://www.lathes.co.uk/page2.html

        2. http://www.sawmillcreek.org/showthread.php?17423-Home-Made-Tail-Stock-Where-to-find-Morse-Taper-Insert

        3. http://www.mcmaster.com/#morse-taper-socket-reamers/=s5bl6u

        4. http://www.mscdirect.com/browse/tn/Tool-Holding/Morse-Taper-Sleeves-Sockets/Morse-Taper-Sockets?navid=12108514





        Essential Features in a Small Lathe
        Screwcutting
        Backgear
        Tumble Reverse
        Provision to fit T slotted cross slide
        2 Morse taper in tailstock
        Set-over tailstock for taper turning
        Gearing to handle on apron traverse

        Desirable Features in a Small Lathe
        Quick-set or 4-way tool holder
        Gap bed (up to 3.5"/90mm centre height)
        At least 0.5"/13mm hole through spindle
        Dial-thread indicator for screwcutting
        Spindle lock to aid removal of chucks
        Automatic disengage to saddle drive
        Provision to mount collets
        Graduated tailstock barrel

        Non-Essential but Useful Features in a Small Lathe
        Screwcutting gearbox
        Power cross feed
        Clutch to headstock spindle drive
        1" (26mm) or larger hole through spindle
        Coolant equipment
        Graduated handle to leadscrew end
        Availability of lever-action tailstock
        Electronic or mechanical variable-speed drive


      • k15n1
        Yes, I understand. It s just a list of features that an experienced machinist has found to be essential. Every feature comes at some expense and I don t
        Message 3 of 10 , May 28, 2014
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          Yes, I understand.  It's just a list of features that an experienced machinist has found to be essential.  Every feature comes at some expense and I don't trust my own experience to know which features are of general use out in the real world.

          I realize that the bar is rather higher in mind of that article's author.  But still, I found it informative and thought it might be of interest here.

          Back to the topic...

          The offset tailstock may be easier to make and more rigid than a compound on the carriage.  Tapers are maybe not the most important thing but when it comes to making machine tools or tooling, it would be needed.

          Seems to me that screw-cutting is an essential and expensive.  Traditional methods are just to dang spendy.  I haven't tried the thread-follower method yet.  That may work, within some limits, especially for large threads.  An alternative is an electronic leadscrew drive.  It would work for ANY thread, which is nice---expensive but certainly cheaper than a stack of change gears.

          What about a dual-cone transmission with a sliding belt?  With light enough cuts the belt drive may be adequate.  The advantage would be that the lathe could make its own screw-cutting transmission.  It could also be used for power feed, at its slowest setting.  I'm assuming foot-powered speeds here.
        • David G. LeVine
          ... And mine: First of all, I have three options: Desirable, mandatory and optional. 1. Screwcutting: Desirable, in many cases there are other options and
          Message 4 of 10 , May 28, 2014
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            On 05/27/2014 10:07 AM, neffk@... [multimachine] wrote:

            Here's my commentary on the "essential" features.


            1. Screwcutting - yes!
            2. Backgear - low speed capability is already part of the design assumptions
            3. Tumble Reverse - no
            4. Provision to fit T slotted cross slide - Cutting T slots would be a challenge without a mill, so this might not be possible.
            5. 2 Morse taper in tailstock - only marginal cost if you're buying an insert [2,4] or buying a reamer [3]
            6. Set-over tailstock for taper turning - can build
            7. Gearing to handle on apron traverse - no, power feed isn't a priority (if I understand this correctly)

            And mine:

            First of all, I have three options: Desirable, mandatory and optional.

                1. Screwcutting:  Desirable, in many cases there are other options and this is not mandatory.
                2. Backgear: Desirable, for larger and/or heavier cuts, it is a lifesaver.  For threading it is necessary.
                3. Tumble reverse: Optional, if only for special operations.
                4. T-slot cross slide: Desirable, It makes mounting stuff much more versatile.
                5. 2MT tail stock: Desirable, any Morse taper would be okay, 2MT is just preferred.  A 1" 2MT socket is pretty inexpensive.
                6. Set over tail stock: Optional, short tapers can be done with the compound.  Needed for long tapers unless a tracer is built.
                7. Apron traverse: Optional, but power feeds are VERY desirable for good surface finish.

            Dave  8{)

            --

            "A word to the wise ain't necessary - it's the stupid ones that need the advice."

            Bill Cosby
          • k15n1
            I m curious about the alternatives for threading. For very small jobs, you can t beat a set of taps and dies, whether price or performance. But anything over
            Message 5 of 10 , May 29, 2014
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              I'm curious about the alternatives for threading.  For very small jobs, you can't beat a set of taps and dies, whether price or performance.  But anything over 1/4 starts getting expensive, at least for a hobbyist in the USA.  I don't know what the availability of taps and dies is in Kenya or other developing countries. 

              Come to think of it, we're all guessing at what's need, aren't we?

              This whole conversation reminds me of marketing/business conversations I hear at work.  I wonder if we could find several different types of sources that could tell us what kind of work is available.  Once we know what kind of work is available or probable, we can work backwards to the features that are needed.
            • drpshops
              Hello The smaller size tap& dies are good up to about 1/2in ,12 to 13mm range. Anything over that you allmost have to have a machine to cut them. I have cut a
              Message 6 of 10 , Jul 1, 2014
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                Hello

                 The smaller size tap& dies are good up to about 1/2in ,12 to 13mm range.

                Anything over that you allmost have to have a machine to cut them.

                 I have cut a 3/4 16 tpi with a die, but you have to have a wrench that is

                somthing like 2 foot long.

                Threading is just a matter of getting the spindle rotation and the carriage travel in the correct ratio..

                 

                 

                 Keith Gutshall

              • Thomas S. Knutsen
                Taps and dies for standarized bolt sizes have only been around since Mr. Withworth did some of his best work (1840 s). Before this, all manufacturers made
                Message 7 of 10 , Jul 2, 2014
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                  Taps and dies for standarized bolt sizes have only been around since Mr. Withworth did some of his best work (1840's).
                  Before this, all manufacturers made their own bolts and nuts, and the tools to make them.

                  Making an set of taps from some extra bolts should not be to difficult, they would require some machining for the taper and the groves, but both of those can worst case be done with hand tools.  With access to an lathe, it would be even better.
                  The heathtreatment of the tap is fairly easy, you protect the threads, preferably with stainless steel foil. Then to cool it, you plunge it into an bucket of water that have been standing over the nigth. When plunging, try to get the thinnest part first, and at an angle to avoid cracking. Some quick heating to an dark straw colour and re-plunging would make for the tempering.
                  The grinding and honing of the cutting sides is perhaps the hardest thing to do without any resources. An sandstone may perhaps be an viable option?

                  I would not use these taps in Stainless or Inconel, but they should work quite well in soft steel and alu castings.

                  Thomas.



                  2014-05-29 19:16 GMT+02:00 neffk@... [multimachine] <multimachine@yahoogroups.com>:
                   


                  I'm curious about the alternatives for threading.  For very small jobs, you can't beat a set of taps and dies, whether price or performance.  But anything over 1/4 starts getting expensive, at least for a hobbyist in the USA.  I don't know what the availability of taps and dies is in Kenya or other developing countries. 

                  Come to think of it, we're all guessing at what's need, aren't we?

                  This whole conversation reminds me of marketing/business conversations I hear at work.  I wonder if we could find several different types of sources that could tell us what kind of work is available.  Once we know what kind of work is available or probable, we can work backwards to the features that are needed.




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                   See  <http://www.gnu.org/philosophy/no-word-attachments.html>
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                • Lance Eggleston
                  I had been advised to plunge straight to avoid warping the metal. If at an angle, more of one side cools before the other, hence warpage. Anyone have a cited
                  Message 8 of 10 , Jul 2, 2014
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                    I had been advised to plunge straight to avoid warping the metal.

                    If at an angle, more of one side cools before the other, hence warpage.

                    Anyone have a cited reference??

                    lance
                    ++++
                    On Jul 2, 2014, at 6:08 AM, 'Thomas S. Knutsen' la3pna@... [multimachine] <multimachine@yahoogroups.com> wrote:

                    When plunging, try to get the thinnest part first, and at an angle to avoid cracking.

                  • Thomas S. Knutsen
                    I have an reference, but its in norwegian: Mekanikkerpermen (the mechanics folder) welding and forgework, page 173. I beleve its covered under hardening in the
                    Message 9 of 10 , Jul 2, 2014
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                      I have an reference, but its in norwegian:
                      Mekanikkerpermen (the mechanics folder) welding and forgework, page 173.

                      I beleve its covered under hardening in the tool and diework book by R. J. Smith but I don't have that in front of me now.

                      Br.
                      Thomas.


                      2014-07-02 17:17 GMT+02:00 Lance Eggleston wheezer606@... [multimachine] <multimachine@yahoogroups.com>:
                       

                      I had been advised to plunge straight to avoid warping the metal.


                      If at an angle, more of one side cools before the other, hence warpage.

                      Anyone have a cited reference??

                      lance
                      ++++

                      On Jul 2, 2014, at 6:08 AM, 'Thomas S. Knutsen' la3pna@... [multimachine] <multimachine@yahoogroups.com> wrote:

                      When plunging, try to get the thinnest part first, and at an angle to avoid cracking.




                      --

                       Please  avoid sending  me  Word  or  PowerPoint  attachments.
                       See  <http://www.gnu.org/philosophy/no-word-attachments.html>
                      PDF is an better alternative and there are always LaTeX!
                    • pokerbacken
                      uhm, references on heat treatment and warping? how about the list below, they all state that a straight plunge is essential for a straight and uniform
                      Message 10 of 10 , Jul 4, 2014
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                        uhm, references on heat treatment and warping?
                         how about the list below, they all state that a straight plunge is essential for a straight and uniform hardening.

                        new edge of the anvil
                        machinerys handbook
                        the art of blacksmithing
                        Sandvik heat treatment guide
                        the complete modern blacksmith
                        karlebo handbok (swedish)
                        Karlebo materiallära (Swedish)
                        Darryl Meier (the man that taught me to pattern weld stainless steel and carbon steel together in the forge).
                        My grandfather
                        My own experience...

                        if you want to test yourself try hardening a straight razor (cutthroat razor) as hard as it will get without it getting uneven hardness or any warping or cracking, then temper it to a even pale straw colour, if you succeed you are really good.

                        now I am going to go of topic a bit.
                        while we are at the forge, if you want to test your skill with forgewelding weld two pieces of 3mm (1/8") thick and about 300mm (12") long steel together into a 600MM (24") straight bar without much of a bulge or "wasp waist" and still fairly straight in the end with no visible crack.
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