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Thread: Shortening MT-3 arbor

  1. #1
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    Default Shortening MT-3 arbor

    Bought a very nice drill chuck from Glacern but the MT-3 arbor is the tang type and won't
    only allow the tail stock to retract far enough before the arbor pops out.

    Leaves 1.5" sticking out.

    How much can I cut off the arbor without having the chuck...stuck?
    Len

  2. #2
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    Copy one of the arbors you already have which does fit? I'm going to guess that you don't have one or this would be obvious.

    1.5" of stickout is a LOT ! ! ! The tangs which form the difference in length are simply not that long. Even if you remove the tank flush to the small end of the taper it's still going to stick out a good inch or so. Which is why I suspect there's something else going on like the tail stock needs special shortened MT tapers. And why I'm suggesting that if you have items which do fit neatly and eject correctly close to fully retracted that you copy them.

    On any lathe I've ever seen it's the other way around. If there is no tang or the taper isn't made a bit longer than normal the items won't eject. In fact I had to make and modify my two live centers to add "tangs" to the back plug to get them to eject at all.

  3. #3
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    While it is your lathe,.....are you sure the tailstock is an MT3 and not an MT2? See the table lined below, if you tailstock barrel is MT3, it would measure 0.938 at the end.

    https://www.morsecuttingtools.com/Ca...ALOG/J0296.pdf

  4. #4
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    What I do.... I wind out the tailstock ram until the overlong arbor will fit in neatly and at that point I read the tailstock graduations and use that as the measure of what to cut off the tang.

    When I do that the arbor ejects when the tailstock ram is wound out to zero.

  5. #5
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    Default

    I have one of the 7x12 lathes in my garage which has a MT2 tailstock. Pretty much any chuck or live centre in the tailstock takes up too much of the tiny bed length and restricts the travel. The tailstock is self extracting, so I cut the tangs off and drilled a clearance hole for the tailstock screw with a flat bottom, so the length of taper was unaffected, but the tailstock would retract more before extracting. I gained about 5/8" between centres and quill travel, which is worthwhile in a small lathe. An alternative to a flat bottomed hole would be a brass plug in the bottom of a slightly deeper hole.

  6. #6
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    Mini lathes have a MT2 taper in the tailstock. OP said MT#3, so that tells me it's not a mini lathe. Right QSIMDO? What brand of lathe are you talking about?
    Last edited by chucketn; 01-11-2019 at 09:48 PM.

  7. #7
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    Before messing up a good taper that might then be too short for your next lathe check several pieces of MT tooling. Also check the tailstock screw itself hasn't for some reason been elongated or is not original. It might be an advantage to put a spacer in at the RH end of the tailstock for the moment to move the screw out to the right.

  8. #8
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    I use a Colchester Bantam with an MT3 tailstock. Like you, when I have a taper with the tang fitted, it hits eject when 1 3/8" of tailstock are still sticking out.

    I have a few drill chucks and other things mounted on shortened tapers - about 2 1/2" long - which eject with the tailstock almost flush.

    My go to Jacobs chuck is mounted like this, and I think the fact that I can use up to 1/2" drills - at low speed, say 100 rpm, for 1/2" - with no turning in the tailstock implies that the fit of my arbors is pretty good. My aims is to have three or four chucks on short tapers - only using tapers with tangs for my large 16N chuck and MT3 drills.

    If a taper with the tang snugs in nicely, even though it sticks out, I'd say there's nothing wrong. Or at least nothing worth messing about for.

    Short tapers in a good socket work fine. You lose an inch when using big stuff - like my massive 25mm three flute core drill - but big holes and long work don't usually go together.
    Richard

  9. #9
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    Quote Originally Posted by chucketn View Post
    Mini lathes have a MT2 taper in the tailstock. OP said MT#3, so that tells me it's not a mini lathe. Right QSIMDO? What brand of lathe are you talking about?
    12 x 36 G4003G Grizzly.
    Len

  10. #10
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    I do not think this can be answered adequately without pictures of it in place in the T/S, and also by itself to see what it looks like.
    1601

    Keep eye on ball.
    Hashim Khan

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