New Owner, Headstock rebuild

[starmatt]

It seems to be a pretty common theme on here, but I picked up a Mark V (1984ish model, as far as the previous and original owner could remember). My father in law has one and I was keeping my eye out for a good deal. It was listed for $200 on craig's list and I talked him down to $150 since he found out after listing that it was blowing the circuit breaker about 10s after turning on (15A breaker, but it also blew my 20A breaker after about 30s). It came with all the standard accessories (lathe, drill press, table saw, sanding disc) and a collection of saw blades and gouges.

So I took a gamble that it just needed some cleaning and oiling and I was mostly right. Here are a couple of problems I am working on fixing:

1. The control & idler sheaves were stuck fast together (obviously in the low speed setting). After quite a bit of oil and a little elbow grease, I got them apart. I soaked them for about 24 hours in wd-40, which I later cleaned off. They still stick pretty good if you push them together. Does anyone have any good advice on fixing this?

I've de-burred the vanes and sanded them pretty smooth with 600 grit paper, which has helped a little, but I'm thinking I might need to get a little more aggressive and use either lower grit or a file (or maybe a wire wheel in a drill). Obviously, I'd have to follow these up with some 600 grit paper and maybe even some higher grit paper to smooth it out after that. The generic advice I found from shopsmith for moving parts was to use a wire wheel, scotchbrite pad, 600 grit paper, and 1800 grit crocus cloth in that order.

2. The teeth on the quadrant arm of the speed control are worn and now the headstock is stuck on high speed. I imagine this is a result of the sheaves being stuck and trying to change the speeds (or maybe trying to change the speeds with the motor off or without being oiled in forever). In any event, I think there is little hope of salvaging the quadrant arm and the worm gear shaft is very slightly bent as a result (might not be a problem with a new quadrant arm). Anyone on here have an extra speed control assembly or even just a quadrant arm (maybe from doing a powerpro upgrade)? I know shopsmith has the assembly for about $50, but I'm on a tight budget and hoping to do a little better than that. I'm keeping my eye on ebay as well, but the speed controls don't show up too often (there is one auction ending later in the week).

I did see someone on here with an upgrade for the quadrant arm, replacing the pin with a bolt and I might do that with a new one, but the legs for the quadrant arm aren't bent and worm is still centered on the quadrant arm, so I don't think it would help this arm out.

Otherwise, the shopsmith is in good shape: The speed control gears are fine (no missing teeth), the quill is smooth in sliding in and out, the motor sheaves are fine (I oiled them to be sure), the belts aren't too worn, there's no rust to be seen except a little on the underside of the legs.

Anyway, I've been using lots of the information on this site and the Sawdust Sessions to help me in my tear down. Keep up the good work.

[JPG]

At the risk of being 'pickey' I must point out that the 'control' sheave is on the idler shaft, and the 'floating' sheave is on the motor shaft. If you are aware of that and understand that then the following is unnecessary.

However if not:

The control sheave is one half of the idler pulley. The control sheave moves, while the other half of the pulley does not.

Similar situation on the motor pulley. The floating sheave moves(pushed by that spring) and the fan portion is fixed.

If the worm gear is bent, it should be replaced. Depending upon the condition of the rest of the speed control it may suffice to replace only the worm gear
and quadrant.
504221 Quadrant Assembly 22.43

504216 Worm Control Shaft 5.33

Pix would help us help you!

[starmatt]

If the worm gear is bent, it should be replaced. Depending upon the condition of the rest of the speed control it may suffice to replace only the worm gear
and quadrant.

504221 Quadrant Assembly 22.43

504216 Worm Control Shaft 5.33

Pix would help us help you!

Yes, I was aware of the terminology, but thanks for the reminder. I also went through the parts list and found the prices from shopsmith, but I am on a tight budget and would also be inclined to recycle parts from other users if they're available. I saw quite a long thread on here about a number of folks who've done the powerpro upgrade, so I thought there might be a few perfectly serviceable speed control assemblies lying around unused.

As requested, here are a couple pictures of the quadrant & worm:




As you can see from the first picture, the teeth on the quadrant are quite worn. When I have the speed control off the headstock, I can get the worm to move the quadrant arm through the whole range, but only by carefully adjusting the positioning. When I put the speed control back on, the worm is unable to adjust the quadrant arm out of the fastest speed setting.

In the second image, if you look carefully, you can see a little daylight under one side of the worm gear (between the worm and the brass ring underneath it). That is the only real indication that it is not quite straight. There is a little wearing on the worm at the top and at the bottom. I wasn't able to get the camera to show that real well.

I will add pictures of the idler shaft assembly (complete with control & idler sheaves) the next time I take it apart.

[JPG]

Yes, I was aware of the terminology, but thanks for the reminder. I also went through the parts list and found the prices from shopsmith, but I am on a tight budget and would also be inclined to recycle parts from other users if they're available. I saw quite a long thread on here about a number of folks who've done the powerpro upgrade, so I thought there might be a few perfectly serviceable speed control assemblies lying around unused.

As requested, here are a couple pictures of the quadrant & worm:
http://www.shopsmith.net/forums/attachment.htm?attachmentid=12003&stc=1&d=1298337467

http://www.shopsmith.net/forums/attachment.htm?attachmentid=12002&stc=1&d=1298337467

As you can see from the first picture, the teeth on the quadrant are quite worn. When I have the speed control off the headstock, I can get the worm to move the quadrant arm through the whole range, but only by carefully adjusting the positioning. When I put the speed control back on, the worm is unable to adjust the quadrant arm out of the fastest speed setting.

In the second image, if you look carefully, you can see a little daylight under one side of the worm gear (between the worm and the brass ring underneath it). That is the only real indication that it is not quite straight. There is a little wearing on the worm at the top and at the bottom. I wasn't able to get the camera to show that real well.

I will add pictures of the idler shaft assembly (complete with control & idler sheaves) the next time I take it apart.

Does the far end(top in your 2nd pix) wobble when shaft is turned? If it doesn't wobble,(out of round/true) then it does not need replacing. If it does 'wobble' remove it and carefully try to straighten. Probably wishful thinking, but worth a try!

The quadrant does indeed look beyond hope!:( Judicious filing to reform the teeth MAY help!

As for the sheaves 'sticking' it is possible that they will never need to travel that close together anyway(key word there is 'possible').

BTW That is unusual(it me anyway) wear of the quadrant gear. It does tend to wear more at that location, but with a different pattern due to the legs bending.

[ddvann79]

Wow! It's like someone took a hammer to one end of the quadrant rack!

I'm inclined to agree with JPG on reforming the teeth. If you have a needle file, that might get you by for a while. I wouldn't be too concerned with the space between the worm screw and the back of the speed control housing. It doesn't look serious, unless it's only evident on one side.

I bet a lot of guys with the PowerPro are keeping their old quadrant assemblies for backup. I know I would.

[starmatt]

Does the far end(top in your 2nd pix) wobble when shaft is turned? If it doesn't wobble,(out of round/true) then it does not need replacing. If it does 'wobble' remove it and carefully try to straighten. Probably wishful thinking, but worth a try!

The quadrant does indeed look beyond hope!:( Judicious filing to reform the teeth MAY help!

As for the sheaves 'sticking' it is possible that they will never need to travel that close together anyway(key word there is 'possible').

BTW That is unusual(it me anyway) wear of the quadrant gear. It does tend to wear more at that location, but with a different pattern due to the legs bending.

The tip of the worm wobbles just a fraction. If it weren't for the deformed teeth on the quadrant, I don't think it would be cause for much concern. It does seem like the teeth on the quadrant are worn more on one side, but when I look to see if the worm is on center with the quadrant, it seems to be (and I can't see any bending in the legs). Maybe the previous owner straightened the legs a little, but it seemed to me like he hadn't given the machine any attention in years. There is also a slight wobble in the pin that holds the quadrant, but again, not enough to shift the quadrant off the worm much.

I was hoping I might get away with the sheaves as they are now, but I can't really test that until I get the speed control fixed (it's stuck on high, so I can't see whether it gets stuck on low speed or not). If I have the time this week, maybe I'll put the sanding disk on and see if I can manually get it down to low speed.

[starmatt]

Wow! It's like someone took a hammer to one end of the quadrant rack!

I'm inclined to agree with JPG on reforming the teeth. If you have a needle file, that might get you by for a while. I wouldn't be too concerned with the space between the worm screw and the back of the speed control housing. It doesn't look serious, unless it's only evident on one side.

I bet a lot of guys with the PowerPro are keeping their old quadrant assemblies for backup. I know I would.

I've got a triangular shaped file, but I'm not sure it's small enough. The space between the worm screw and the speed control is only on one side, but it only produces a very slight wobble (just enough that the worm gets stuck on top of some of the very deformed teeth on the quadrant). If the teeth weren't deformed, I don't think it would be a problem.

There are a couple of guys with powerpro upgrades who've contacted me about the parts. We'll see how that goes.

[JPG]

I've got a triangular shaped file, but I'm not sure it's small enough. The space between the worm screw and the speed control is only on one side, but it only produces a very slight wobble (just enough that the worm gets stuck on top of some of the very deformed teeth on the quadrant). If the teeth weren't deformed, I don't think it would be a problem.

There are a couple of guys with powerpro upgrades who've contacted me about the parts. We'll see how that goes.

You need a very small file with at least one flat face. Tapered may help.

[RobertTaylor]

realisticly the quadrant is toast. someone must have tried changing speeds without the unit running. if i didn't leave it at bill mayos i might have a quadrant in worn but much better shape than that one. the retaining loop bearing had froze and wiped out the metal curved piece if you can get the rivets out to swap it with yours.

[starmatt]

realisticly the quadrant is toast. someone must have tried changing speeds without the unit running. if i didn't leave it at bill mayos i might have a quadrant in worn but much better shape than that one. the retaining loop bearing had froze and wiped out the metal curved piece if you can get the rivets out to swap it with yours.

I just worked out a deal with RonKlein for the whole speed control assembly and the idler shaft assembly as well. Once they get here and check out, I'll be glad to send the extra parts to anyone who needs them for the cost of shipping.