Shopsmith Forums

Acquired another Mark V to restore and have been following Jacob Anderson on Youtube for the headstock teardown. This time I bought a rusted mess and the found that nothing rotated, but the motor did hum. This is my first teardown. Pulled motor and and it runs fine but the upper control sheaves are bound up and I cannot seperate them. I've prettiy much stripped the headstock out after freeing up the quill All bearings spin freely although not sure how quiet they should be. I guess I should probably put in all new bearings while it's all apart. Is there some sort of procedure or trick to seperate the sheaves. I don't see any set screws or anything. From what videos I've seen the outer sheave (the one farthest from pully) should just slide off. Any help would be greatly appreciated.

I am assuming you have the headstock on bench and the motor and motor pan are separated from the headstock.

Yes the control sheave should slide off the end of the idler shaft(with the speed control removed).

The control sheave bore and the idler shaft are likely 'gunked' up.

Penetrating fluid and persuasion will be required.

The control sheave bore is steel and the shaft is steel.

Tricks are to get the fluid where it works best and the same with the persuasion.

Worst case you may need to apply persuasion to the aluminum outer part of the control sheave and that may make replacing it necessary since it can get bent.

ATF and acetone 50/50 is recommended for the fluid.

BTW is the idler pulley fully closed(slow speed position).

We like pix!!!

diplexer wrote:Acquired another Mark V to restore and have been following Jacob Anderson on Youtube for the headstock teardown. This time I bought a rusted mess and the found that nothing rotated, but the motor did hum. This is my first teardown. Pulled motor and and it runs fine but the upper control sheaves are bound up and I cannot seperate them. I've prettiy much stripped the headstock out after freeing up the quill All bearings spin freely although not sure how quiet they should be. I guess I should probably put in all new bearings while it's all apart. Is there some sort of procedure or trick to seperate the sheaves. I don't see any set screws or anything. From what videos I've seen the outer sheave (the one farthest from pully) should just slide off. Any help would be greatly appreciated.

A good long soak with penetrating oil. Not WD40, PB Blaster or better yet Kroil.

Thanks for all your advice. I have everything stripped out of headstock. Will try the atf/acetone method and just wait. I assume 24 hrs. should be enough for it to work. Hopefully I can nudge them apart with damaging. I guess patience is the best cure. There was a lot of rust all over this machine as it was kept in someones shed for years without use. Definately needs belts as the poly V has tears on the sides. I got it cheap enough with many accessories and a good cleaning and some parts should restore it.

While you have everything apart check the Speed Control Assembly. Specifically the teeth on the porkchop and worm gear (see arrows in the picture below). Also check the teeth on the speed control dial, the speed control idler gear and the back side of the speed control handle. If the previous owner tried to change speeds with the pulley sheave frozen in place it may have damaged teeth on the speed controller assembly. If they are fine than great if not they can easily be replaced. While you have it apart check all the headstock parts for wear and damage. If any parts have pitting from rust consider if they need to be replaced or will they still work smoothly as they function.

OK. Got the sheaves separated but upon inspection they appear to look pitted inside in some areas. It doesn't look like corrsion but rather bad casting or machining when made. Is this normal and will it affect operation?

diplexer wrote:OK. Got the sheaves separated but upon inspection they appear to look pitted inside in some areas. It doesn't look like corrsion but rather bad casting or machining when made. Is this normal and will it affect operation?

Pictures would help.

This is what the inside of both sheaves look like. Any reccomendations or thoughts on how this would affect operation?

I assume that cavitation is fairly shallow, so I think it will have minimal effect on operation.

Thanks. I was hoping for that. They are not very deep. Should I leave them alone or try sanding them out?