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Spindle Wedge Lock for Removing Stuck Chucks

ksimolo

Aluminum
Joined
May 23, 2010
Location
NY, USA
I saw on Ebay that someone is making 3D printed spindle wedge locks for removing stuck chucks. Personally, I have good luck with engaging the back gears and pushing down on a long bar grabbed by the chuck jaws rather than hitting a shorter bar with a hammer. But this might be worth purchasing or making if you have a 3D printer.
 
I've been toying with the idea of making something for the tailstock. I get tooling stuck in there that doesn't have the right length for the ejector and usually use a small V block and crank the tailstock to wedge it out. Not ideal because I have to hold the block at an angle. A block of nylon or delrin that is the shape of the quill would be better for my TS. I have a grab bag of Delrin cut offs inbound so I may get a chance to fab something soon.
 
There's at least two reasons due to simple physics threaded chucks get stuck. One, once the tightening torque gets high enough the male/female threads start to stretch within the metals elastic limit just like any off the shelf nut and bolt does. But the other main reason is due to friction between the back plate and the face of the chuck register on the spindle. It's even worse if the back plate was made from any steel that was handy instead of cast iron. But there's a simple real old school machinist's trick to prevent that stuck chuck problem from happening. Cut out a thin, light weight single layer of card board washer just under size to fit the recess in the back plate and just over size to fit over the spindle threads and plain unthreaded area of the spindle nose. Paper and card board are remarkably consistent in there thickness so won't cause any additional axial run out of the chuck or work. That card board acts as a cushion between the two metal surfaces and prevents that frictional binding. It's also helpful to soak the card board in any light oil for a few minutes so it soaks up a bit of oil. That also helps a bit with friction, but more importantly it prevents the card board from absorbing any water during high humidity conditions and causing possible rusting of the parts. I find it real strange the number of people using threaded spindle noses that still don't know this very simple and common trick.
 
I've been toying with the idea of making something for the tailstock. I get tooling stuck in there that doesn't have the right length for the ejector and usually use a small V block and crank the tailstock to wedge it out. Not ideal because I have to hold the block at an angle. A block of nylon or delrin that is the shape of the quill would be better for my TS. I have a grab bag of Delrin cut offs inbound so I may get a chance to fab something soon.

I made a new lead screw for my tailstock that is 3/8" longer than the original. That solves the problem of tools too short to eject.
 
...Cut out a thin, light weight single layer of card board washer just under size to fit the recess in the back plate and just over size to fit over the spindle threads and plain unthreaded area of the spindle nose. Paper and card board are remarkably consistent in there thickness so won't cause any additional axial run out of the chuck or work.

I use a piece of parchment paper (wax paper also works) for this washer. Since using it, I haven't had any difficulty removing my chucks,
 
I made a new lead screw for my tailstock that is 3/8" longer than the original. That solves the problem of tools too short to eject.

I want to make a new screw for mine as well. What kind of material did you make yours out of?
 
This is how i got the backplate off my Bradford. Even a 5ft I-beam would not budge it. The chuck was probably on there for the better part of 50 years so I had to get a little creative. Dismounted the chuck, took a diamond sawzall blade almost to the threads, cracked the plate with a chisel.

Before:

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After:

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I have good luck with engaging the back gears and pushing down on a long bar grabbed by the chuck jaws rather than hitting a shorter bar with a hammer.

I used to do that then I was taught that that is how you break the gears. My Bison chuck says to put a screw in the back, block the screw and turn ion the lathe. So far that has not let me down. Chuck actually came with the screw.
 
I bought a strap wrench(rubber strap). Wrap it round the pulley and a bar in the jaws. Better than risking a broken gear tooth. Will be trying the paper washer trick mentioned too.
 
I usually do not have an issue removing chucks. I have had my 10K since 1980, but I already did break a tooth on my bull gear years ago. I use oil every time I change a chuck. I like the idea of this plastic block. I ordered one as a just in case thing. Cheap insurance. I think the soft plastic is the correct answer because it will compress enough to even the load across all the engaged bull gear teeth.
 








 
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