Ugh, setscrew on threads???!

[tony ennis]

Ok, I started working on the opposite end of the spindle. I got a collar to move, but not far. Peering into the set screw hole, I see this:



So, what do I do? I can't get the collar off... by twisting it...

[John Stevenson]

Dimple it with a drill and when you replace it use a copper pad at the bottom of the hole and a cup screw, not a pointed screw [ or just grind the point off ]

.

[Optics Curmudgeon]

Looks like the back end of an Atlas lathe spindle. There's supposed to be a lead plug protecting the threads, but any other soft metal will do. Wad up some solder, works fine.

Joe

[dalee100]

Hi,

Pretty common cheap method to lock a collar to the shaft. I do it all the time at work .

The photo doesn't look too bad, I've seen worse. You stand a better chance of getting it off if you have a pin spanner wrench. One like this should do the job, [URL=http://www.grainger.com/Grainger/items/1FJ44[/URL]

They aren't cheap, but they do work well.

dalee

[Charles Lessig]

Screw a bolt into the hole as a wrench but not against the threads.
Turn the collar until it starts to bind and tap it in all directions with a
small hammer. Loosen the collar and repeat. The hope is to hammer the burr
back down and not destroy the collar threads. This works quite well
much of the time. Best regards, Charlie

[Oldguy]

How about grinding a 60 degree V on the end of a small rod (old drill ?) and using it to deform/reform the dimpled area so the collar will unscrew.

Glenn

[S_J_H]

Tony, Grab a big pipe wrench if you have to for that collar. If you mar it then just re turn it to make it beautiful. It's just a threaded collar.
The threads will be very easy to restore with just a threading file if they burr up a tad during removal. Squirt a little oil into the threads beforehand.
And , you have to impact that chuck off. You are only dealing with a threaded nut in reality. Unless it has truly rusted tight it will come off with a very hard sharp rap by hand. No wood! Wood will absorb away all the impact.
I'll tell you what, this old artisan lathe with it's 2" 8tpi thread locks the chuck TIGHT as the face register fit is so good!. I can apply enough force by leverage alone to tip the near 400lb machine over before the chuck will even come close to breaking loose after just spinning it on by hand. But a sharp hard rap and it's loose instantly.
I have wrenched on cars for near 30 years. There is a definite skill to hand impacting. It's not about taking a 15lb sledge and following through like you want to destroy something. It's almost a wrist action type blow.
I wish you were local so I could help but best of luck as I want to see your machine restored!
Steve

[BadDog]

My lathe spindle rear collar/nut was like that. I thought I would never get it off. When I did, I fixed the threads, but the Royal collet dog has to be locked on by that screw. So I did what I've done before and since. I took a piece of solid copper wire from a short scrap of 10-2 house wiring. Cut off a piece about 3/16 long, bent it about 90*, used a vice to fold it on down and sorta shape into a hocky puck, then put that beneath the grub screw. Had to take it apart again not too long ago. The collar scewed right off, a bit "stiff" to start, but that was from the copper deformed into the threads. It worked loose(ish) in about 1 turn and came off with no damaged threads.

[torker]

I've used lead shot many times under those type setscrews.

[Forrest Addy]

Don't go and bull moose the collar nut off with pipe wrenches. What's wrong with you guys offering advice like that? You watch too many Schwartzenegger movies. You'll damage the threads; quite possibly ruining them.

There's a better, gentler way one that uses intelligence and craft instead of raw brawn: put the deformed metal back where it came from.

Make up a little narrow cold chisel and use it with a light hammer to reach in and restore the damaged threads to form again by wedging them without actually cutting anything. Test the nut from time to time using the contact burnish to detect which raised surface need a little more attention. Be sure the exposed threads and are clean and you use plenty of extreme pressure oil (I like worm gear oil) when you unscrew the nut. If you meet gritty resistance stop instantly and cycle the nut gently to resistance and back. Sooner or later you'll get past the resistance without galling the metal. A good mechanic works wiithout unnecessary drama or causing damage to the parts.

Use a dog point or a cup point set screw to replace the pointy screw you have. Use annealed copper or a lead shot between the thread and the screw. A soft solder blob works fine too.