Unstick ML7 chuck

I second the (already acknowledged by OP) suggestion to tighten a piece of hex stock in the chuck jaws.

I'll add that if such equipment is available, then you can consider applying a pnuematic or electric impact gun, fitted with a suitably sized socket, to the protruding end of the hex stock. (I am describing a proper impact tool, I have no experience using a hammer drill for the task - maybe one of those might suffice, too ?)

Set the tool to turn in the appropriate direction, adjust its impact torque to the lowest setting. Use less air pressure than commonly specified for pnuematic impacts. There is no need to block rotation of the spindle. In my experience, a brief actuation of the tool will bring about the desired result.

I've never done so, but if there is a concern about damage from the impact tool, consider making a torque-limiting adapter. Machine a groove down to a diameter that will shear at a figure you are comfortable with. Or make a 2-pc adapter held together w/ a shear pin. Pre-test/calibrate the adapter by using a torque wrench on a sample adapter held in a vise.

Thanks for the suggestion Eddy but as noted earlier I tried this method without success!!!

The Amateur's Lathe contains a design for a stop mounted to the right of the carriage; left-hand designs depend on whether a gearbox is fitted.

Eddy Curr:

I very much like the idea of loosening the chuck by repeated blows without immobilising the spindle and will try this if the need arises.

Instinctively, however, it would seem that the blows should be "radial" rather than axial and that a hammer tool (as opposed to the mechanic's air wrench) would be less suitable.

The easiest route I've found on a Myford M series is to use the backgear

A bit of wood on the bed (at a right angle) and a roundbar into a hole in the belt pulley

A bit of pressure on the bar from left to right (moves pulley backwards about an inch or two) and the chuck unscrews itself

Zero violence required

I think the reason it works so well is because the 6:1 ratio (or so) of the backgear allows you a lot of control over how much pressure to apply (plus the block of wood gives you a decent 90 degree lever at the spindle nose) and the chuck is removed with the absolute minimum pressure necessary to achieve success

Edited By Ady1 on 14/10/2017 09:55:06

Ady1, thanks for this. Can you provide anymore detail relating to the hole in the belt pulley? Did you drill it? How deep is it and what diameter? I see your sectional belt. This is what I plan to do should I ever need to replace mine. I'm a little afraid to take the bearings out to replace it.

I too had this problem some years ago,but I managed to break a gear in the process.

With this in mind,I would be very interested in that product called "Never Seize". Who makes it,who sells it ?

I think that Ali clamp is a good idea,will make one up soon [before I break another gear !! ]

The sheer hassle of replacing it !!

Larry here is a shot of the material I use.

After reading and re-reading all the suggestions in this thread I took a closer look at my ML7 and note that there are grooves/slots in the sides of the Bull Gear. So I'm wondering why I can't use them to 'lock' everything in place. Here is a photo of the side of the Gear.

Here is a photo of the tool I made from a chunk of 3/8 aluminum.

Here is a shot of it in place. I push the pin into the slot and have cut a small slot in the pin that I can use to gently pry it out of the grove when I'm done.

Seems that it should work pretty well especially if the chuck is maintained as has been suggested. Of course my chuck is no longer stuck so I really haven't yet had a chance to 'test' it properly.

Can you provide anymore detail relating to the hole in the belt pulley?

There was already an oiler hole in my pulley of about 9mm, I use an 8mm bar

If you are going to drill your own hole make sure the pulley casting is solid and not hollow at the drilling point

GL

Edited By Ady1 on 15/10/2017 11:25:05

Thanks Peter for your reply. I was unable to open your pictures,but I came across stuff yesterday which I think is much the same as your Never Seize. I will get a can of it,while also making an Ali clamp.

Peter,sorry about this,but I have just found your picture of Never Seize !!

You know what they say about OLD AGE ?

Thanks again.

Hi

I am not at all keen on using the back gears to assist removing a chuck, however using a piece of wood as shown by Ady1 above may help, not as shown but placed under the front jaw over the front bed way.
Having placed it in position and keeping your fingers clear as rapidly as you can rotate the chuck back then slam it forwards against the piece of wood that is resting on the bed, the inertia of the spindle and its pulleys should do the trick and unscrew the chuck. Note the backgear is (Not) engaged during this process. Cast Iron teeth do not like being overloaded.

My old pre war Colechester occasionally would need this process to remove a stubborn chuck, it always worked.

Regards
John

Surely that's just going to tighten the chuck up even more?

Well spotted

Gee Neil its been ten years since I had to do this. I think you are right the piece of wood should be over the back of the bed to unscrew the stuck chuck.

My current lathe has a German Din standard spindle similar to a Camlock but with bolts. easy to remove

I do remember however that the method worked well on my old Colechester. When I got that lathe the back gears were ruined I had to find replacements. not easy. **LINK** Second image down a Colchester Master as made circa 1930 to 1939.

Regards
John

Edited By John McNamara on 15/10/2017 13:46:43

Edited By John McNamara on 15/10/2017 13:47:05

Yes, I had noticed that you mentioned trying an impact wrench in the OP.

I don't suppose you might be willing to elaborate ? Perhaps mock up and post a picture or two of the approach that didn't work for you ?

Incidently. Notice that a raw piece of hex bar stock is not necessary, a chisel or punch of a size that mates with an available impact socket will do nicely.

Be certain to run the impact tool in the appropriate direction.

Eddy, I have a very similar electric gun as you show but didn't work for me. All that happened was the hex nut began to get rounded corners. I tried it with the belts tightly wrapped together, no luck. So I added a wedge of oak between the gear next to the bull gear and the back gear underneath, no luck again. My son-in-law thought it was because the impact is so short that the belts and wood wedge gave just enough to allow the impact to move without actually putting any impact on the chuck.