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colchester student headstock MT5??

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  • colchester student headstock MT5??

    hey gang, need your help.. anyone out there know if the headstock
    taper in the colchester student (old roundhead) is in fact a 5 morse?

    Tony's site says it isn't:

    "The 1.5" bore No. 3 Morse-taper headstock spindle (bushed down to No. 3 Morse from something close to, but not actually, a No. 5 Morse) carried an American Type L (long-taper) nose"

    but I've seen a few projects online and its referred to an MT5.
    kinzer's 5C chuck build page says:
    "The lathe spindle has a #5 Morse taper"

    I don't have an MT5 anything to test. It would stink to measure
    as if its not a 5 its probably pretty darn close enough to screw
    up my measuring

    I can get an MT5-MT3 adapter for a lot cheaper than I can make one.

    They look like truncated MT5's .. but would hate to spend the $ and find
    out it isn't.


  • #2
    Originally posted by Tony
    They look like truncated MT5's .. but would hate to spend the $ and find out it isn't.
    Well it certainly sounds like its a #5. I'd get an adapter from a reputable company such as MSC, Enco, Travers Tool, etc that has an acceptable return policy. That way if it does not fit, you can return it.

    Or, is there someone in your neck of the woods that has a #5 MT adapter that you could borrow?


    • #3
      I can't answer about the student, but my Clausing Colchester 15x48 has a, as far as I can tell, non-standard taper.

      In fact, I just measured it yesterday, and it tapers .060" per inch. Morse tapers are closer to .050"/inch.

      I was thinking mine might be a 6MT, but as it turns out, it's not.


      • #4
        yes it is a MT5 or at least mine is.. manual / most sites say mt4.5 ....which I spent several hours turning to as precise a size as I could... to have it disappear without trace


        • #5
          Alot of lathes of that vintage use a Jarno taper, I think a 12 or 13?


          • #6
            Same story for a Harrison L5 with L00 spindle nose.

            The taper isn't quite MT5.

            I was able to pick up the MT3 adaptor sleeve for £20, but it took a couple of years!
            Paul Compton


            • #7
              Originally posted by Tony
              They look like truncated MT5's .. but would hate to spend the $ and find out it isn't.
              Why not measure it? Pretty simple with a couple indicators.

              I used my DRO and a DTI, but if you don't have a DRO, just set up a 1" or more travel indicator on the bed and a DTI on the taper inside the spindle. Zero both, then move carriage 1" and read the DTI.

              Then reference this google books link and see if you find a match.

              Edit: I should add, double the DTI readout to find your taper, as the taper is on diameter.
              Last edited by hsm'er; 03-15-2012, 05:58 PM.


              • #8
                I recall something about a thread with a lathe spindle having a 4 1/2 Morse Taper. Do not remember the context, but am wondering if this may be the case.

                I usually do not rely on Wikipedia, but in this case I found this:


                Morse Tapers come in eight sizes identified by whole numbers between 0 and 7, and one half-size (4 1/2 - very rarely found, and not shown in the table). Often the designation is abbreviated as MT followed by a digit, for example a Morse taper number 4 would be MT4. The MT2 taper is the size most often found in drill presses up to ½" capacity. Stub (short) versions, the same taper angle but a little over half the usual length, are occasionally encountered for the whole number sizes from 1 through 5. There are standards for these, which (inter alia) are sometimes used in lathe headstocks to preserve a larger spindle through-hole.

                Last edited by Dr Stan; 03-15-2012, 05:52 PM.


                • #9
                  Tony pm me your address and I will send you a MT5 tool to test the fit.
                  How to become a millionaire: Start out with 10 million and take up machining as a hobby!


                  • #10
                    some seem to be 4.5....easy to measure the max size at the front of the spindle... no need for accuracy (0.5mm is plenty iirc) as there is a conciderable difference in size


                    • #11
                      It's not a standard morse, I fell into the trap and bought a 5 reducing sleeve, cut the end off so it would fit only to find the tapers do not match.

                      I'm still searching for a proper reducer, they sell for a lot of £££ when they pop up.

                      Would have been too simple to use a standard taper I guess
                      If it does'nt fit, hit it.


                      • #12
                        Thanks guys. The mixed results were what I feared.
                        I think my easiest option is what Doc recommended, I'll borrow
                        an MT5 and give it a try.

                        Sounds like odds are against me but worse comes to worse I'll just
                        cut one. Figure easy enough to take the chuck off and set the compound
                        with an indicator.

                        Thanks all!



                        • #13
                          Got a big box of headstock tapers here but no idea what they are off.
                          All short series so if someone wants to measure what they want i may be able to match them up.

                          Pretty sure some are Colchester and / or Harrison.

                          They came from Crawfords when they were having a clear-out.
                          Only problem is they are in a cupboard somewhere ..................

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


                          • #14
                            Truth be told I actually have the nose bush that take it down to MT3..
                            however its a bit buggered. In particularly the OD of the bushing (the
                            mystery taper side) has a "lump" in at the front and 180* at the back
                            which seats it a little cocked.

                            Using a 3MT test bar (10" long or so) it gave me about 0.010" TIR at the
                            end of the 10".

                            I moved it around in diff locations (and the test bar relative to the bushing)
                            to determine that:
                            1. the taper in the spindle appears ok (though a little pitted)
                            2. the 3MT internal taper is okay.

                            What I decided to do today is mount the little home made TPG and clean
                            the inside taper on the spindle.

                            Still some pitting, but cleaned up nice.. didn't take very much off. 0.0005"
                            total, perhaps.

                            Next I'll mount the bushing backwards on the test bar, put the test bar
                            in a 4jaw, and without changing my compound angle, clean up the outside.

                            That should give me a much better fit than I'm getting now.

                            Buying the bushing was a less frightening options.. but then I thought,
                            what the heck, the internal taper is no good to me without a matching
                            bushing anyway.

                            I'll post pictures sometime this weekend.


                            PS John, thanks all the same for the offer!


                            • #15

                              I have a Clausing-Colchester 8000 series lathe (1980 vintage) and the manual lists the spindle as having a 5MT in the spindle. The adapters for a 5-C collet and No.3 Morse tapers are much shorter than a standard Number 5 drill taper.