Removing a 3 jaw chuck off a lathe

remp49 said:
Set the lathe spindle to it"s lowest speed. This should keep it from turning. Open the jaws on the chuck half way and place the end of a 3/4 to 1 inch bar of steel across two of the jaws. Give the other end of the steel bar a good wack. It should come loose if the chuck is threaded on.
Please post a picture of the chuck mounted on the spindle. I do not think any of the newer Chinese lathe have thread on chucks. It would come off if the spindle was revered.
Click to expand...

This is what we would do years ago with the old Southbend Lathes; but use a block of wood and a hammer on the jaw. Off it comes.
 
laurencen said:
years ago I saw a hobby machinist use the turn it on 2 threads and turn the lathe on to tighten, yes it worked but when he stopped the lathe it un threaded off the nose and proceeded to do carnage in his garage

The jaws are hardened compared to say hot rolled steel but it will put a mark on the jaws, its not how hard they are but the level of deformation they can stand
Click to expand...

It doesn't make sense... if he installed the chuck using power, it normally snaps on over tight... If the chuck came off when he stopped the lathe, the chuck was not tight.

And my chucks and jaws are hardened steel... much harder than an non heat treated steel bar. My steel bar has not marked the chuck nor jaws since 1971 when the lathe was purchased. If anything will deform with excessive pressure it will be the steel bar...
 
Properly installed threaded chucks don't just fly off as soon as we put them in reverse. My lathe has a thread on chuck and it's fine for light cuts in reverse. Just did a couple of internal threaded adapters for Winchester 97 barrels where I ran the threading cutter upside down on the back of the hole and used reverse to cut from the inside to outside. A lot nicer than crashing into the bottom of the dead ended hole. Being as it was a slower RPM and light cuts not a thing moved on me... Nor did I expect it to.
 
Even the jaws on my Chinese Lath chuck are super hard, I have tried to center-punch them for identifying one from the other for repositioning work pieces and couldn't make mark in them...had to use a grinding wheel in a dremmel tool.
 
On an old monarch, I used to push the chuck backwards 1/quarter turn as it was moving away from me then snap towards me and chucks would come loose
 
guntech said:
It doesn't make sense... if he installed the chuck using power, it normally snaps on over tight... If the chuck came off when he stopped the lathe, the chuck was not tight.

And my chucks and jaws are hardened steel... much harder than an non heat treated steel bar. My steel bar has not marked the chuck nor jaws since 1971 when the lathe was purchased. If anything will deform with excessive pressure it will be the steel bar...
Click to expand...

first one I have seen unscrew, he turned the lathe on using the clutch lever, turned it of, the brake stopped the spindle and it spun off, as for the steel bar versus Aluminum, use what you desire, I know hardened jaws are harder, I also do lots of machining and cold rolled can bruise hard steel,
 
coyote said:
One of my lathes is setup like that and I put a bar in the open jaws put it in back gear and take the slack out of the gears then give it some blows with the palm of my hand it comes off easily but I change it regularly so it aint stuck.

I tried taking one off a south bend once it never came off so needless to say I didn't buy that one , they can be tight but once removed it will be easier next time.

If it won't come off like that you're going to have to figure out a way to hold the rear of the spindle and use a longer bar good luck
Click to expand...

I have used the back gear method and left the spindle lock pin in however one day I noticed a tooth missing on one of my back gears and figured that was probably the cause. So make sure you disengage the spindle.
 
You must log in or register to reply here.
Back
Top Bottom