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Craftsman/Atlas Drawbar/Collet Chuck advice?

Discussion in 'ATLAS, CRAFTSMAN & AA' started by Olddaddy, Jun 13, 2017.

  1. Olddaddy

    Olddaddy H-M Supporter - Premium Content H-M Supporter-Premium

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    So, I have both a draw bar and collet chuck with collets for my Craftsman 12" lathe. I figured out the drawbar works with one size cutter, which I have, (see pic). I managed to thread the collet chuck onto the spindle and figured out that by turning the chuck body clockwise it comes off. I inserted a collet into the chuck, but for the life of me cannot get it to tighten down onto the cutter. I assumed turning it counter clockwise would tighten. Questions are, how does it tighten up? Do I need both? Would the drawbar be sufficient for simple milling? Or, do I want to have a pile of collets and a chuck in the toolbox?
     

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  2. Randall Marx

    Randall Marx United States H-M Supporter - Premium Content H-M Supporter-Premium

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    Hi Charlie
    Nice looking lathe! I have not seen a collet chuck like that one before, but it is interesting. The endmill holder and drawbar is what I would want to use for milling, since they were definitely made for that function. (the parts on the bed in your second picture) I'm sure someone else will be along that likely knows more about it than I do.
    Randall
     
  3. wa5cab

    wa5cab Downloads Moderator Staff Member H-M Supporter-Premium

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    Charlie,

    I have never seen a collet chuck like that one. Can you give us a legible closeup photo of the plate riveted to the OD? And one of the rear face with it removed from the spindle?

    On what you called a drawbar, the drawbar is the threaded rod, centering bearing and handwheel. The part that the drawbar is screwed into is a 1/2" bore cutter holder on a 3MT shank. It is made to hold cutters with 1/2" shanks. It really is not intended for use on cutters with Weldom style shanks (those with a flat ground across the shank) but will work OK with them if they have 1/2" shanks. What you are missing is the set of four reducing bushings made to fit into the 1/2" holder and hold round shank cutters with 7/16", 3/8", 5/16" and 1/4" diameter shanks. The bushing sets turn up on eBay from time to time.And cutters in between those diameters are still readily available, although it is unfortunate that the set of bushings didn't include one for 3/16" shanks. One thing that you should never do is to try to use one of the reducing bushings with a Weldon style cutter. I'm admitting nothing but will say that is was a good thing that I had two of the 1/2" bore holders and more than one set of the bushings. :crushed:
     
  4. Olddaddy

    Olddaddy H-M Supporter - Premium Content H-M Supporter-Premium

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    Hahahaha, confession if for the weak, or the guilty.........I fooled with the collet chuck after dinner. By turning the outer shell clockwise it is removable. This allows you to change the collet. There is hole in the inner body where it looks like a tool fits to allow you to tighten the inner body on the spindle threads. Turning the outer shell counterclockwise and wedging a screwdriver across two of the socket head screws tightens the collet down on the bit. Something is missing in the process, but it does appear to work. I am guessing this is a very old piece which was made obsolete by newer designs.
     

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  5. Olddaddy

    Olddaddy H-M Supporter - Premium Content H-M Supporter-Premium

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    I found some collets that look like they have something to do with the drawbar. They thread onto it and when inserted into a tapered collar they fit into the spindle hole. However, the bushing makes the bar too short to reach the collets. Perhaps there are shorter bushings? As above, something is missing in the process, but I think these collets are somehow meant to be used with the drawbar.
     

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  6. scwhite

    scwhite United States Active Member Active Member

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    I am not really sure but it looks like a Pratt Bernad
    Copy
    Pratt has a linkage going done to the bed under the collet closer . And you push and pull that handle
    To lock it or unlock it
     
  7. scwhite

    scwhite United States Active Member Active Member

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    Yep that is what is missing is the linkage and the clamp the the bed
     
  8. scwhite

    scwhite United States Active Member Active Member

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    You should have a big bearing inside your closer
     
  9. wa5cab

    wa5cab Downloads Moderator Staff Member H-M Supporter-Premium

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    Charlie,

    I still don't recognize the front-mounted collet closer but if someone thinks it looks like a Pratt-Burnerd, I wouldn't argue. I once had a front mounted closer made by Royale. Didn't really look much like yours but it did have a part underneath that went down and clamped to the ways. You didn't show any photo of just one of the collets but one make with a nose that looks similar is Warner & Swasey. Unlike the MT and C series of collets, which are closed by pulling on the rear of the collets, they are closed by pushing on the front. Like a Dremel collet except much larger.

    The other collets that you have are 2MT. They would directly fit an Atlas 618 or mill. The native size for the 12" would be 3MT, which except for the long nose are the same size as the 3MT cutter holder that you have. The 2MT collets that you have with the 3MT x 2MT sleeve adapter that originally came with all Atlas lathes except for the 6" would work but you would need a longer draw bar on a 10" or 12". Or a shorter centering sleeve. To determine the required sleeve length, do the following:

    Remove the centering sleeve from the draw bar. Insert the 3MT x 2MT adapter sleeve and any one of your 2MT collets into the spindle nose. Without the centering sleeve, insert the draw bar into the spindle while holding the collet and adapter firmly in the spindle and screw the draw bar into the collet just enough that you are sure it has caught the first thread. Turn the hand wheel while holding it up to roughly center the bar in the spindle 6 full turns (there should be an empty hole in the wheel that you can use as a counter), Pull on the hand wheel slightly to ensure that the collet and adapter are seated in the spindle nose. Carefully measure the distance between the left end of the spindle and the front of the hand wheel. Remove the draw bar, collet and adapter from the spindle and mount a chuck on it. Make a new steel spacer that looks like a really thick shoulder washer. Diameter should be the same as that of the existing centering sleeve. Total length should be the measured distance plus about 1/4". Bore a 3/8" diameter hole through it. Turn down one end to a diameter of about 25/32" (slip fit in the spindle bore) until the length of the larger diameter is the same as the previously measured distance. De-burr, etc. and you're done.
     
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  10. Olddaddy

    Olddaddy H-M Supporter - Premium Content H-M Supporter-Premium

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    You described exactly what I was thinking of doing. I could easily make a longer drawbar or shorter centering sleeve. Perfect solution unless someone wanted to trade 3MT for my 2MT collets.
     
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  11. wa5cab

    wa5cab Downloads Moderator Staff Member H-M Supporter-Premium

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    Well, the shorter sleeve is obviously the way to go. It's easier to make and doesn't take up as much room. However, trading your almost complete 2MT set for a 3MT set plus some cash difference would probably make more sense. Most sets that I have seen for sale are 7 pieces of 2MT and 11 pieces of 3MT. Your set appears to be missing the 3/16" collet. MT collets cover 1/8" to 1/2" and 1/8" to 3/4" by 1/16" increments. The clamping range of MT collets is about +/- 0.005" so not always usable for work holding.
     
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