# Central Machinery scroll chuck-does it come apart?



## visenfile (Dec 28, 2021)

All the youtubes show the smaller chucks coming apart easily after a plate is removed, but I have not found any instructions on disassembling a 6" scroll chuck.    This one is a 2004 with only .001" runout !  The condition of the lathe is good, but the chuck looks like it has never been opened and cleaned.  After some head scratching I now ask for help from anyone who knows the secret.  The only nomenclature on the chuck is a sticker,  "Hua Pai."  

The picture attached shows the back side.  I see what may be a parting line inside the bore so I made the washer shown and tried tapping-nothing.  Last guess was that perhaps the halves were held together by a spanner nut.  Tapping produced no movement.  I have not tried a press because "it ain't broke..."  Any help greatly appreciated.


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## Mitch Alsup (Dec 28, 2021)

My guess is that you still have 6 bolts left to remove.
All I see done, so far, is to remove the D1-3 bolts.


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## T Bredehoft (Dec 28, 2021)

Just a suggestion.  Back each of the 6 socket head screws out two full revolutions. stand the chuck on it's side and tap each of the six screws heads in sequence until they all are flush with the surface. I'll bet that'll move something


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## jwmay (Dec 29, 2021)

visenfile said:


> "it ain't broke..


I'll just leave this here...lol


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## visenfile (Dec 29, 2021)

All screws out in attempts.  The pic shows a washer being marked with 3 "transfer punches."  Then drilled and fastened to the center to provide a place to tap/push in an attempt to separate the unit.  As noted nothing moved.   I will try tapping loosened cap screws . Thanks


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## visenfile (Dec 29, 2021)

Got it  Thanks to Bredehoft's suggestion I had the chuck on end  under bright light and saw what turned out to be the hidden parting line.  It was faint at best.  Then I noticed two threaded holes opposite one another on the outer circumference and the lightbulb went on.  Just take 2 of the M6 x 1.0 cap screws and turn them into "pushers"   Voila. Spent some time breaking the sharp edges everywhere.  The picture below shows the 2 pusher screws and also 2 shallow counterbores they bear against.


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## visenfile (Jan 14, 2022)

I debated posting this comment here as it is really "Does it also go back together and mount properly?"  I read a 4 pg thread from 2018 here where a member had difficulty with back plate mounting a similar chuck and was guided, among other ways, to blue and read the spindle-chuck interface .  

When I disassembled the chuck I noticed the 8 cap screws which sit in counter bores near the center were loose (see pic #1), but wrote it off to age and use.   When I assembled I tightened them with an allen wrench.   All was well until I tried mounting the chuck , but found an air gap I could not close of about .030."  After several hours I decided to blue the spindle nose and found contact scratches where the cap screws protruded and touched the spindle nose.  Apparently the PO's had found the problem and just backed out the screws.  The screws were removed and trimmed back about 2-3 threads which solved the problem.


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