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D1-4 spindle, should chuck fit flush ?

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  • Rich Carlstedt
    replied
    FACT CHECK TIME

    Having read all the posts, I decided to do a little leg work, and it was rather interesting. I had a machine shop Seminar at a tech college 60 miles way and they have a lot of lathes with DI Spindles. So I asked the instructor for a .001 piece of shim stock. He only had a .0015 so I used it on the 8 lathes.
    I found that on 6 of them, I could not insert the shim, or see light.
    On one, there was a .002 clearance and the other was cocked, at maybe .004".
    Turns out the .002 would not snug tight, but was also not "registered".
    That means the O--O marks between the chuck and the spindle were not alligned. You always mount a DI with these marks. When the instructor released the chuck and reset it with the marks, it came in to .000" , but he did put a heavy twist on the wrench.
    The last chuck was....loose on one pin ...and also not alligned
    But guess what ? Not all chucks AND not all spindles had registration marks !
    (3 spindles and 2 chucks were void on this)
    So maybe if your chuck is not pulled against the spindle sufficiently, you have a problem wirh the "connection"

    Moral of the story is that attention on these issues are important to note and do occur and should be addressed. I know the instructor (friend of mine) is greatful that I brought up the subject,
    It may have prevented damage or injury .

    Thank You Home Shop Machinist for the opportunity to promote shop safety !
    Thank You also to Mr Forrest Addy..your proof was in the pudding !

    Merry Christmas all
    Rich

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  • DeereGuy
    replied
    I know this will probably sound like overkill to most of you and certainly way to slow for the production guys....
    I always....tighen mine just snugging by hand then I actually use a torque wrench and work my way around taking them to 50 ft lbs....Don't remember where I got that figure at...I know it was after I had shoulder surgery and was recovering.

    In addition to the above...when I do get a new chuck I always try all the positions and note the best runout..then make a mark on the chuck so I always index it to the mark I have on the spindle.

    Leave a comment:


  • rkepler
    replied
    Originally posted by TR
    Yes. The force I used on the breaker was not too big. It was just easier. Yes, tight fit. One whack of the rubber mallet and the chuck was loose.
    One thing that I've found to help is that you make one pass just nipping the cams up, then a second pass tightening them to the final torque. Pulling the backplate in evenly helps a lot on the level of torque needed.

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  • TR
    replied
    Originally posted by Ian B
    Sounds like it's on the taper pretty tightly.

    Have you tried to remove it yet?

    Ian
    Yes. The force I used on the breaker was not too big. It was just easier. Yes, tight fit. One whack of the rubber mallet and the chuck was loose.

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  • Ian B
    replied
    Sounds like it's on the taper pretty tightly.

    Have you tried to remove it yet?

    Ian

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  • TR
    replied
    Good news. I used a breaker bar to close the .004" gap and now have TIR less than 0.03mm. Pretty good. Pretty tight fit.
    I purchased some spare d1-4 cams just in case. The supplier told me they keep lots in stock because of demand. Typically machinists use a breaker bar to close gaps between the chuck and spindle face and sometime the cams break. Hard to believe.

    Thanks for all the good advice.

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  • TR
    replied
    Originally posted by deere_x475guy
    TR, are all the pins on the back of the chuck screwed in the same length?
    yes, I even tried pins from my other chucks.

    Leave a comment:


  • Mcgyver
    replied
    Originally posted by TR
    The manufacture says the chuck should fit flush against the spindle face. I have a 0.004" gap near number 1 jaw. No gap near the 2 and 3. Maybe I should use a breaker bar to try and tighten it just a bit ?
    this is not a problem brute force will solve

    presumably the pin 1 is engaging with the cam, ie like deere guy says, the pin is the right distance out so the cam catches it?

    Like I said earlier, that is your problem, its mounting like a swash plate. As earlier suggest you need to now determine if its the lathe spindle or chuck that is at fault - first thing is to try mounting any other tooling you have and check it with the feeler gauge....if everything else mounts ok dollars to donuts its the chuck

    Leave a comment:


  • DeereGuy
    replied
    Originally posted by TR
    I have measured. < 0.01mm or very close to zero.
    TR, are all the pins on the back of the chuck screwed in the same length?

    Leave a comment:


  • TR
    replied
    The manufacture says the chuck should fit flush against the spindle face. I have a 0.004" gap near number 1 jaw. No gap near the 2 and 3. Maybe I should use a breaker bar to try and tighten it just a bit ?

    Leave a comment:


  • PSD KEN
    replied
    My 14X40 seems to have a slightly large taper.
    With 3 chucks ( 4 - 6 - 8") & collect chuck, after snugging #1 a bit I have to indicate the chuck, tweaking each came a smidgen slightly.
    With a Bison I end up with .001.

    Grinding this, that or the other 0.0001 is beyond my capability.

    I seldom change chucks so I can live with it.

    Leave a comment:


  • Forrest Addy
    replied
    I have a vague recollection of some engineering analyst guy worked out the merits of the A1-D1 series spindle noses Vs the L-x series. Six of one half dozen of the other using gage line dia as a comparison feature for stiffness providing the supporting bearing fit is larger than the gage line dia.

    However what stuck in my mind is repeat positioning accuracy. Radially, both A1 - D1 and L-x series spindle noses are about the same. The L-x series is axially variable because the taper draws more or less with collar torque, whereas, the A1-D1 series draws up and stops when the flange face mates. The difference is 0.001" or so and 0.0001" or less but them numbers are important only to some people.

    Adding, some people suggest a "torgue sequence" of the cam-locks A`11 - D1 spindle nose to securing repeatable mounting of their lathe spindle tooling. I submit if the fit-up is clean and blemishes are stoned flush it should make no difference which cam-lock is snugged.

    And for the record, if Old Tiffie wants to run radial clearance in the taper of his cam-lock equipped lathe that's his privilege. Anyone buying his stuff later should keep his mods in mind. It's a simple matter to face back the spindle nose flat and correct it to incorporate the right amount of draw.
    Last edited by Forrest Addy; 12-14-2010, 05:11 AM.

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  • Rich Carlstedt
    replied
    When you pay one company $200 for a back plate you expect quality
    When you pay another company $42 for a back plate you "hope" for quality

    The 42 dollar guy is counting on your comment tiffie

    Rich

    This whole discussion shows why the L Series (ie Lo, Loo) are the finest spindle noses you can have.... in my opinion.
    Forrest, you are correct with the ANSI Standard B5.9-1967 .
    They added the DI-3 andDI-4 specs at that time

    Leave a comment:


  • rklopp
    replied
    There is a tolerance on the taper angle built into the standard. The male gauge has diameter-over-pins dimensions for 0.250-in pins located flush with the inner and outer faces of the taper. The tolerances are +/-0.0001". The female gauge taper is to be a "good Prussian blue fit" on the male gauge taper, so it picks up the taper angle tolerance. When fitting the female gauge to a spindle, there is a tolerance on the gap of 0.000" to 0.002" for D1-4. When fitting the male gauge to a chuck or whatever, there is the same +0.002" tolerance on the gap. The male gauge corresponds to the smallest allowable spindle taper. Thus, the minimum allowable gap before tightening the cams is 0.000" and the biggest gap is 0.004", for in-tolerance D1-4 assemblies. In no case is there allowed looseness in the taper fit. The gauges are applied with hand force. There are no provisions for forcing the gauges onto the taper using the cams.

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  • Richard-TX
    replied
    Grind? Why grind? I see no reason to grind when the factory that makes this stuff does not grind the chuck mounting plates.

    If you go too far with the cut of the tapered portion, just take a little off the face.
    Last edited by Richard-TX; 12-13-2010, 09:39 AM.

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