Speed control DOA?

[reubenjames]

It's been a number of years since I upgraded to the Power Pro and thus since I've been in the guts of a Mark V. Fired up a headstock from the 80's and the speed control was pretty difficult, going down especially. Still gutting it and plan on replacing some of the bearings that are questionable. But I noticed the speed control, even when roughly cleaned up a bit, was still sticking. Snapped some pics but this looks like it was used a long time with some issues to me. Maybe I just don't remember what these look like though. Does this look like it was rubbing and wore poorly to you?

[BuckeyeDennis]

I see two issues. The first is a goodly amount of normal-looking wear from the rubbing of the worm. It's pretty well centered, though, a good sign. The second issue is that the individual teeth are bowed. If not for the wear pattern, the crests of the teeth would be banana-shaped. That tells me the speed control has been operated with excessive force, and the tooth deformation may prevent it from operating smoothly.

For only $22, I'd install a fresh new quadrant while I had it apart.

[JPG]

Bananna? Only in yer dreams.

They be 'straight' teeth.

Now those are not in bad condition. Some judicious filing will make it 'usable'.

I recommend Bill Mayo's 'fix'.(replace the tension pin with a screw and straighten the legs').

If the quadrant gear were a true worm gear the wear would be much less.

[dusty]

What's to be straightened? The legs look okay to me.

[BuckeyeDennis]

Bananna? Only in yer dreams.

They be 'straight' teeth.

Now those are not in bad condition. Some judicious filing will make it 'usable'.

I recommend Bill Mayo's 'fix'.(replace the tension pin with a screw and straighten the legs').

If the quadrant gear were a true worm gear the wear would be much less.

Look closely at the crest of the teeth in the first photo. What I was trying to say is that they should be straight, but have been deformed into a crescent shape. That deformation is somewhat disguised by the wear from the worm gear.

[everettdavis]

Since Aluminum is malleable, it might be prudent to entice it back into shape with some gentle persuasion, before filing if deformation appears to have moved material opposed to removed material as in more severe cases.

With a suitably shaped tool steel stamp, one might effectively reshape the threads with a minimal filing to dress the faces back to near original.

Has anyone done that successfully yet?

Everett

[reubenjames]

Dennis is correct and it's especially bad on the teeth nearest my thumb in that picture. Before anyone asks about my delicate hands, yes, my thumb is the one that looks like one of your pinky sausage fingers. Anyway, the flats of the teeth are not flat anymore and that does not make for smooth turning. I need to go mow the farm tomorrow so I will pick up my box of goodies. I have an extra speed changer in there as well as fairly new belts and a two bearing quill. Hope to swap out old for slightly less old.

[rpd]

Since Aluminum is malleable, it might be prudent to entice it back into shape with some gentle persuasion, before filing if deformation appears to have moved material opposed to removed material as in more severe cases.

With a suitably shaped tool steel stamp, one might effectively reshape the threads with a minimal filing to dress the faces back to near original.

Has anyone done that successfully yet?

Everett

Fitzhugh said he had success, See this post http://shopsmith.com/ss_forum/viewtopic ... 08#p169308

[garys]

Consider replacing the worn part. I did that on mine a couple of years ago because mine looked that bad too.

[charlese]

I think you guys are looking at the wrong end of the problem.

Look at the movable sheave just outside of the motor sheave. When pulled by hand, the movable sheave should slide smoothly whole closing the spring.

Failed lubrication of the shaft beneath the spring is often the cause of hard down speed movement of the speed control. Really!!!

There is always a cause for wear, and often it is not in the worn part.