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Small twist on a 5C depth stop...

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  • Small twist on a 5C depth stop...

    I've been using both my lathes rather extensively lately, almost exclusively in 5C collet mode. First I discovered I needed a second collet depth stop (I had just the one I'd made a few years ago) and then I discovered I had some long, thin pieces (5/16" rod) that were slightly undersized stock. Due to the undersize, the collet gripped poorly- it held the part well enough, but it could rotate, tilting in the collet jaws like a seesaw.

    So, I killed two metaphorical birds with one stone:



    The new stop has a sort of circular V-block on the end, which tends to center the stock thusly:



    The opposite end has a point, which can be used to center stock that has a centerdrilled hole, or short lengths of tubing.

    Works great, so far. It's a bit rough in finish, but hey, it's just a tool.

    Doc.
    Doc's Machine. (Probably not what you expect.)

  • #2
    Great idea Doc! That should do the trick.

    I noticed that the adjustable depth stop rod on the old Sioux valve grinder has the same setup. The original chuck rollers were pretty short so a valve would probably rock a little without it.
    Milton

    "Accuracy is the sum total of your compensating mistakes."

    "The thing I hate about an argument is that it always interrupts a discussion." G. K. Chesterton

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    • #3
      Use one of these.



      5C body and holds an ER32 collet.
      No gaps and they will hold undersize parallel without bellmouthing.

      .
      .

      Sir John , Earl of Bligeport & Sudspumpwater. MBE [ Motor Bike Engineer ] Nottingham England.



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      • #4
        Collets

        The ER-32 collets in a 5C adaptor is a feature of the "Spindexer" I bought from Arc Eurotrade (UK) that, as I recall, John Stevenson designed. I have not seen this feature anywhere else on any other "Spindexer". I can and do use my 5C and ER_32 collets in the same Spindexer. A top job!!!

        5C collets are very fussy as regards size of the work they are holding, where-as ER collets have a 1mm "gripping range". My ER-32 collets will grip anywhere in the range of say 12 -13mm (which includes 1/2"). I use my 5C collets from my grinder in the 5C adaptor in my Spindexer as in John Stevenson's pic.

        Any relatively thin/long part hanging out of the rear of a lathe collet or chuck at relatively high speed/revs is liable to "spin-off" and hit the hole through the lathe spindle. It should be retained/constrained by a "spider" (which is a method retaining the work).

        It can be by way on a fitting such as in the original post. It can also be by way of a soft (wood, plastic, nylon etc) cylinder that is just a relatively neat sliding fit into the lathe spindle. It is drilled to be a relatively close fit on the job and can be hack-sawed about 3/4 of the way through along its length. It will retain the work quite well and can be easily made/replaced and inserted into and removed from the lathe spindle as required.

        Any part protruding out of or beyond the rear of the lathe spindle bore is a very real potential hazard. If it is relatively long and thin and at relatively high speed/revs it may just suddenly "throw-off" at 90 degree and whip around at lathe revs. Most people remember it and guard against it even if it only happens once!!

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        • #5
          Originally posted by John Stevenson
          Use one of these.
          -Those would be fine for individual items, but I'm making 20 to 30 parts at a time. If I have to get out wrenches to insert or remove the workpiece, I might as well just use a normal chuck.

          With the 5C lever closer, I can stop the spindle, remove the part, insert the next one, and restart the spindle in about three seconds.

          Doc.
          Doc's Machine. (Probably not what you expect.)

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          • #6
            Originally posted by Doc Nickel
            -Those would be fine for individual items, but I'm making 20 to 30 parts at a time. If I have to get out wrenches to insert or remove the workpiece, I might as well just use a normal chuck.

            With the 5C lever closer, I can stop the spindle, remove the part, insert the next one, and restart the spindle in about three seconds.

            Doc.
            You stop the spindle before changing parts? =))))

            One of the good things about leaving the spindle running is that the parts tend to center up almost instantly. Now I turn the spindle on before putting even the first part in the machine, it's just too easy to get things running true.

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            • #7
              Great tool!!!!!

              Oh, and I dont stop the spindle with the lever collet closer either, thought thats how they were meant to operate.. I dont know.. JR
              My old yahoo group. Bridgeport Mill Group

              https://groups.yahoo.com/neo/groups/...port_mill/info

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