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Threading On A Turrett Lathe.

Discussion in 'QUESTIONS & ANSWERS (Get Help Fast Here!)' started by solost, May 18, 2016.

  1. solost

    solost United States Iron Registered Member

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    I'm pretty thrilled to be the new owner of a 16" X 6' turret lathe (SB) but I am a bit puzzled about the lack of a compound rest. The cross slide & tool posts are quite stout and will undoubtedly withstand heavy loads if need be, but without a compound rest how does one cut a 45 degree bevel or cut threads without the ability to feed the cutter in at a 60 degree angle? I must be missing something.
     
  2. Bob Korves

    Bob Korves H-M Supporter - Premium Content H-M Supporter-Premium

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    Those lathes were made for production work, doing one job repetitively day after day, year after year, with dedicated tooling. Different machines were set up to make different parts. Most threading was done on automatic screw machines. Randy Richard in the Shop, on YouTube, has some nice recent videos of doing turret production style work. Check him out:
    https://www.youtube.com/user/Catfish6945/videos
     
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  3. Andre

    Andre Active User Active Member

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    Threading on turret lathes or screw machines, as far as I know, is all done using geometric die heads, die holders, or taps.

    For threading, you can feed straight inwards and cut on both flanks of the threading tool. It just requires a stiffer setup and a really sharp tool.
     
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  4. Tony Wells

    Tony Wells United States Former Vice President Staff Member Administrator

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    You don't have a lead screw and half nuts on a turret lathe, so threading in the conventional sense you can't do, unless it is some oddball special order turret machine. Andre is correct about the die heads, etc.

    As far as bevels and such, you have to slab them on with a form tool. You don't cut long tapers or large bevels. There may be special accessories for your machine, but I doubt it.

    Turret lathes generally aren't sought after by HM'ers because of this. They got HP a plenty, and are heavy and accurate (unless clapped out), and the power feed on the turret you will love for drilling, especially if you have a lot of it to do.
     
  5. firestopper

    firestopper H-M Supporter - Premium Content H-M Supporter-Premium

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    When I was in HS, I worked in a production MS and operated a screw machine. We made Sunnen honing machine knockoffs so many small parts needed. Set up was fun but standing there baby sitting the machine became monotonous to say the least. The stock was feed using weights and cables and became my primary job for well over 100K part runs.
    Turret lathes are neat, but like mentioned are for production. I would find a "widget" project and run a bunch for $$, then buy a conventional lathe.
    Post up a picture of your machine!
     
  6. solost

    solost United States Iron Registered Member

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    Thanks so much for all your thoughts on this. This lathe is quite similar to my SB 14-1/2", just a bit newer, less wear and a cool new turret to work with. It does in fact have a lead screw & a quick change gearbox as indicated in the original brochure so it has most of what it needs to cut threads on the outside of a 12" pipe. I know it is intended to expedite production work which usually doesn't involve that kind of threading, but it seems a shame to limit the versatility of this model by eliminating the compound rest. It could be a nice thing to use the double station cross slide for speeding up certain jobs but a quick change tool post (Aloris eg.) would give one nearly the same advantage. I will enjoy it the way it is for a while, but I may end up exchanging the existing cross slide with a conventional compound rest.
     
  7. 4gsr

    4gsr Global Moderator Staff Member H-M Supporter-Premium

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    There's no law that says you need a compound on your lathe to cut threads. It's nice to have, but not necessary to single point a thread with one.
     
  8. eeler1

    eeler1 United States Dang, buggered that up too!! H-M Supporter-Premium

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    What they all said. Not intended for one off work. But if you have the qc gearbox you should be able to rig up something to get it done.
     
  9. Tony Wells

    Tony Wells United States Former Vice President Staff Member Administrator

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    Still need half nuts and the QC box must have thread ratios. Are they there? Don't assume jut because it has a QC box that it will thread. Who would want to change gears on a production machine? Make sure they are marked for TPI or MOD, and that there are half nuts.

    Any chance of a pic of this lathe?
     
  10. eeler1

    eeler1 United States Dang, buggered that up too!! H-M Supporter-Premium

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    While we're at it, how about a thread dial? I have a Logan 11" turret lathe in progress, similar to Randy Richards. It's the same as other Logan lathes of that size, but lacks a tailstock, thread dial, QC gearbox, and compound. In fact, the cross slide isn't set up for a compound, but is slotted instead. And comes with a tailstock turret and production cross slide. So the same, but way different. I suspect yours is a similar set-up, an engine lathe fitted with turret lathe cross slide and turret instead of a tailstock and typical apron.
     
  11. Reeltor

    Reeltor United States Active User Active Member

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    When I was desperately searching for a nice lathe at a reasonable price I came across a Craig'sList add for a local seller with a Warner & Swasey No. 4 turret lathe for $850. Seller spent over an hour trying to tell me that you could single point thread on it. I didn't buy it and am glad I continued my search. Your lathe is good for a lot of things, threading isn't one of them. Great machine to have but for general use you may want to shop around for a "standard" lathe. 2 lathes are better than just 1 :)
    Just for fun here is a photo of the W & S #4 that I passed on.
    W & S Lathe $850 007.JPG
     
  12. 4gsr

    4gsr Global Moderator Staff Member H-M Supporter-Premium

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    Warner Swasey did make a optional quick change threading box for the 4A and 5A turret lathes. I don't remember how the lead screw/half nut works on the carriage. It was offered on the "oilfield" setup. The QCGB would only cut certain threads such as 3-1/2, 4, 5, 6, 8, 10, 11-1/2 TPI. These are common thread pitches found on pipe.
     
  13. solost

    solost United States Iron Registered Member

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    I haven't run a serial # check yet but it does appear pretty much identical to the one pictured in the original parts catalog that came with it. It does have a half nut lever (so I assume it actually has half nuts inside the apron- haven't run it yet). The gearbox chart lists all the same rates/thread pitches as my 14-1/2 does. Several of you suggested threading "straight in" which didn't register with me until just now... DUH! The simplest solution is always the right one, thanks again all! Not sure if the pic will work or not... here goes SB16TL.jpg
     
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  14. Reeltor

    Reeltor United States Active User Active Member

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    That is a fine looking lathe!
    From here it looks like there isn't a reason why you can't cut threads with it.
     
  15. eeler1

    eeler1 United States Dang, buggered that up too!! H-M Supporter-Premium

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    Wow, that's the real deal. Any tooling for it?
     
  16. solost

    solost United States Iron Registered Member

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    Not to speak of, just the original quick change tool post & a hand full of 5C collets. Fortunately I have some tooling from my 14-1/2 that should work fine. Probably have to make some tooling for the turret but that's part of the fun!
    I re-powered my 14-1/2 with a single phase motor but I think I'll try a phase convertor on this one. I don't like the idea of loosing 1/3 of the power though, sounds like a rotary convertor might be the best choice. Still have some research to do.
     
  17. Shadowdog500

    Shadowdog500 United States Active User Active Member

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    You don't absolutely need a compound to cut threads. I've noticed that some of the machinists in other countries never use the compound to thread, even if the lathe has one.
    Chris
     
  18. benmychree

    benmychree United States John York H-M Supporter-Premium

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    The SB turret lathe was a modification of their standard engine lathe, so it just has a bed turret and cross slide added to it. It would be easy enough to attach a compound rest to the Tee slotted cross slide if desired, or find a standard cross slide to replace it and find a tailstock to replace the bed turret. Obviously, the SB turret lathes are quite light compared with their dedicated cousins, the purpose built turret lathes; they (the SBs) are not intended for heavy work, both from the standpoints of ridgidity and power.
     

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