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removing compound on colchester student

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  • removing compound on colchester student

    The set screws have come loose keeping the dials attached to the compount on my colchester student. So I'd like to remove the nut on the end, remove the dials and crank and put them back in. Yet, for the life of me I can't figure out how to remove the dials? I took the nut off the end and what happens is the whole screw wants to come out - I just need to remove the handwheel/crank then pull the dials out far enough to put the set screws back.

    HELP please.

  • #2


    • #3
      Try here while you`re waiting.



      • #4
        Funny, I did this on my old round head Colchester 12" Dominion last weekend. For the Mark 1 (round head) Student it went like this:
        Remove the retaining nut on the handwheel. Unscrew the compound leadscrew.
        The bushing carrier (about 2" dia., the stationary 0 reference and ball oiler are found on it) is held in place by two hex socket head screws. Mine was badly ridged, so I faced it off smooth, then polished it with crocus cloth. I deepened the counterbores to account for the material removed by the facing, and reinstalled.

        On to the screw and dial. The end of the compound screw shaft is splined. The compound screw handle is splined to fit on the screw shaft. I used a piece of brass to tap the screw shaft from the handle. Make sure it lands on something soft. Now comes the fun part. On my old Dominion, there's a straight knurked thumbscrew in the handle. This locks the dial via an angled point on the end of the screw and a ball bearing sliding in a hole bored in the handle body. There are also three other *spring loaded* ball bearings holding the aluminum dial to the body of the handle. You might try putting the handle in a plastic bag and pulling it apart -- it would have saved me some searching for springs. I bought replacement .250" ball bearings.

        The handle body had ridges and scoring which matched those on the mating surface of the piece I called the bushing carrier (I'm a bit fast and loose with the terminolgy here). This I fixed by installing the handle backwards on the compound screw and facing it off smooth. I used a piece of 1/2" PVC plastic pipe slit lengthwise to protect the compound screw threads while clamped in the tree jaw chuck. I also used a live center in the tailstock to get better accuracy, After cleaning up the scoring, I again polished with crocus cloth.
        Finally, I cleaned up the bores in the handle and replaced the springs and ball bearings, and the locking thumbscrew and ball bearing. Assembling this was a bit tricky, but I managed on the second try,

        Reassemble and lube with oil.

        It was a vast improvement in smoothness and feel. The dial turns easily and locks tight with a turn of the thumbwheel.



        • #5
          Great info. Thanks panchula. Might post back up as I'll try this some night later this week. LOL on the ballbearings and springs - been there done that with other projects.


          • #6
            Thanks again for the info.

            Got the compound shaft off with a press - just a little pressure and it slid right off.

            Eek, now I figured out why the hex socket screws came out - they were likely never in. Apparently they aren't quite long enough. They measure 3/8" long, but I guess should be at least 1/2". Can't find any hex sockets in 12x24 that length so on to the next alternative I suppose.