Control Sheave Self Destructed

Culprit · Post by **Culprit** » Tue Mar 19, 2013 11:23 pm

Hello all,

I haven't logged onto the forums here in a while because I've been too busy using my Shopsmith. I've made 30 something pens since we last spoke, and used every other function (except the table saw and jointer) for various jobs around the house including bandsaw, jigsaw, drill press, lathe, belt sander, and disk sander. I'm certainly a Shopsmith convert - this has not proven to be a fad that passed after I rebuilt my Greenie and the 1980's version that I sold to my brother. It's proven to be the perfect machine for my half of the garage. And the extra time (and help from some of you) to add the reversing switch and re-wire the motor was VERY well worth it, especially when sanding on the lathe, but it has been useful for disk sanding as well.

Anyhow, everything has been humming along great since the rebuild until last night.

I was planing some 8 inch wide red oak rough cut lumber when my headstock started making a funny sound. The headstock was still driving the planer, but something just wasn't right. I stopped, unplugged, and popped off the inspection cover. I saw a fine metal dust coating everything, the button bearing bail was MIA, and there was a crack in the control sheave snout, and it was sitting at an angle.

I dropped the motor, pulled the speed control, and pulled the control sheave out. Not good. The key in the shaft had eaten the bore of the control sheave. Note how it's nowhere close to round anymore. Not to mention the pile of shavings (which do stick to a magnet - not just Aluminum).

Everything was properly lubricated and all the bearings were good. The only thing I can figure is that the day before while planing the planer cutter head grabbed on some grain in the oak and stopped while the headstock kept spinning. I assumed that the Gilmer clutch did it's job. I shut down, freed the workpiece, and continued on. But apparently the clutch didn't give quick enough and at a low enough torque value - which concerns and confuses me because I tested the clutch when I rebuilt the headstock and it tested good after I sanded and reassembled all the fiber and metal disks.

Anyhow, the idler shaft end that fits into the control sheave is still good to go. The end of the key is a little deformed, but the shaft is good. The idler shaft bearing is still good. The button bearing bail is still missing. I'm guessing it's wedged between the bottom of the motor and the pan, but I shook it pretty good and nothing rattled or fell out. Guess I'll pull the motor from the pan to know for sure. The v belt has a nick, but is otherwise okay.

I blew and cleaned all the metal powder out of the headstock and motor pan.

So I guess my next step is to find and buy a pair of sheaves. And like I said earlier, I'm a little concerned that the Gilmer clutch didn't prevent this - assuming that the planner head stoppage during use was what caused it. I know I tested the clutch to the book value during the rebuild, but without looking at my notes I don't remember for sure what that is. 8-10 ft lbs sounds familiar though. Is that right? I will chuck a socket in my 4-jaw chuck on the right side of the headstock with a torque wrench in the socket, and hold the disk sander attached to the lower left side of the headstock and test the clutch again before I put new parts in it.

Do y'all have any words of wisdom for me? Am I missing any other possible cause here?

billmayo · Post by **billmayo** » Wed Mar 20, 2013 12:13 am

First, lack of enough lubrication causes most of the problems in the headstock. I have seen too loose Gilmer belt or sticking motor Floating Sheave which allows some slack in the drive train. I believe this may cause a hammering effect on the drive train as you apply load/chisel to the work being done.

I some times offer a complete reconditioned Control/Idler assembliy on Ebay (billstoolz) if anyone would be interested. Thanks.

charlese · Post by **charlese** » Wed Mar 20, 2013 1:46 am

Sorry, but I just can't believe the lubrication was good enough to prevent this. Believe me! I've been there! After replacing my control sheaves, and the shaft, and the key I kept the lubrication levels religiously at 10 hour intervals. Also used more oil than called for - more than a few drops into the hole. Extra oil kept the thing running for years!!! The extra oil will also make the little end bearing and loop stay happy!

Since you didn't buy a new machine I assume the damage had already been done and all you could do is make it last a little longer.

Recommend you also replace the key! It has most likely been compromised.

Once again - I first tried to go with just the control sheave with the sliding tube and had to replace it with the whole works in a few months of work..

wa2crk · Post by **wa2crk** » Wed Mar 20, 2013 12:59 pm

Never saw a control sheave shaft crack behind the hub before. Possible cause, I would assume, would be the worn keyway and keyway slot having been used for a long time. Probably before you got the machine. The wear on the keyway and shaft is more than likely greater at the bearing end than at the interior. This , I think, would cause the pully to run "cocked" on the shaft and put excessive strain on the junction of the shaft and the sheave. I am surprised that there was no excessive vibration before this happened.
Anywho a new control sheave, idler sheave and possibly the idler shaft also if the bearing seems to be damaged. ( I would not suspect the idler shaft bearing at this time because they are really tough and don't go bad easily.
Replace the parts and lubricate liberally when reassembling and all should be OK. Good luck.
Bill V
And yes a new key also as mentioned earlier.

JPG · Post by **JPG** » Wed Mar 20, 2013 2:07 pm

At a minimum, control sheave and key. Been there done that. Still a bit noisey, but I have not(yet) determined why. A total refurb is in the near future.

My guess would be that the control sheave keyway was worn to begin with(the reason I had to replace mine).

Along comes the sudden stoppage and the control sheave gave way before the clutch had an opportunity to prevent damage.

Since you were planing, I assume a fairly fast speed was being used which placed the control sheave out towards the end of the key which limited its torque tolerance.

FWIW the planer needs a big motor to run at faster speeds.

Culprit · Post by **Culprit** » Wed Mar 20, 2013 11:18 pm

Thanks for the feedback guys. I found the button bearing bail on the garage floor today. It must have popped off when the control sheave snout cracked and it started flopping around off axis. And then it must have slipped out when I dropped the motor pan. For what it's worth the button bearing is still good - not seized.

Bill, I'll check the floating sheave on the motor to make sure it wasn't/isn't sticking. I hadn't thought of the possible hammering effects if the floating sheave sticks allowing the belt to run loose. The Gilmer belt tension is good.

And JPG, you're right. I was running between P and Q while planing that width/hardness and taking light cuts on each pass. I hadn't thought through it yet, but yes, that would put the control sheave pretty far out on the shaft, not leaving much of the key engaged to transfer the power - or absorb the hit when the planer head crashed. Yes, a larger motor would be nice.

You're all right - I won't be reusing the key. I'm probably going to buy a complete idler shaft with sheaves and idler bearing. I really don't know if the keyway was already worn when I got the machine or not - I certainly didn't detect anything visually while cleaning and inspecting. I would like to think I would have noticed it during the teardown, but it was my first Shopsmith (and I've only done two so far) so I probably wouldn't have known if the fit on the shaft was looser than it should have been.

Thanks again for helping me think through this.

Culprit · Post by **Culprit** » Tue Mar 26, 2013 4:09 pm

I bought the complete idler shaft assembly from Bill on eBay, so I should be up and running in no time. Thanks again guys!

Culprit · Post by **Culprit** » Mon Apr 01, 2013 11:29 pm

The FedEx guy delivered my new idler/control sheave shaft assembly on Friday compliments of Bill and eBay. It cost about $4 more than some other guy selling them on eBay, but for that $4 extra Bill threw in a large (4 oz) bottle of ZoomSpout oil and an idler bearing retaining washer. Not to mention the confidence of buying from a known person which means I am assured that the idler bearing and button bearing are good-to-go, and the fact that Bill refaces the sheaves that he ships.

I got it all installed Friday night, put a good amount of oil in the snout of the control sheave, left it in drill press mode overnight, and put it back together on Saturday. My headstock runs smoother and quieter than it ever has since I have owned it. Also, there is no more heat buildup if I lay my hand on top of the headstock while running. Since this is one of only 2 Shopsmiths that I have rebuilt, the only one that I have really used, and certainly the only Gilmer I have used, I just figured that amount of heat was normal. But now I know differently.

I also chose to put the link-belt back on. I ran the link-belt for a short time when I first got the machine up and running, but I replaced it with a traditional v-belt when I added the reversing switch since the link belts are marked with a directional arrow. But since the v-belt had a nick in it from the control sheave giving up the ghost, I figured why not try the link belt running forwards and backwards and see how it works. What's the worst that could happen?

So far (about an hour of use running backwards while sanding pens) it is working great. And when I sand pens, there is a lot of starting and stopping to sand with the grain before moving to the next grit, and to measure fit.

I can understand why the link belts are marked directional because if you're installing it on a one-direction machine, it only makes sense to optimize it and install it the "correct" direction, but I really don't foresee having a problem running it backwards. Even if one of those little tabs sticks out the wrong way, I doubt it will grab anything. At most, it might just wear the tab prematurely.

Has anyone else run link belts backwards for an extended period of time?

PS: that ZoomSpout oiler is the berries. Thanks again, Bill!

Does anyone know what weight oil that stuff is, or how it compares to 3 in One? The bottle says it's a paraffin base, but I don't know what 3 in One is. I'll have to try my highly scientific oil viscosity test - put a drop of each on a painted metal surface (top of the washing machine) and see which one spreads out faster.

billmayo · Post by **billmayo** » Tue Apr 02, 2013 10:49 pm

Nick Engler at the Shopsmith Owners weekend in 2008 made me aware that the factory people was using the Zoom Spout Turbine Oil. I have gone through quite a few dozen of the bottles since then with excellant results. I include a bottle with any headstock rebuild or any control sheave sale. I believe it is a 10 weight oil but never saw any specs on it.

I am a firm believer that the control sheave has always been getting too little oil applied. About 90% of the problems I find are from the lack of oiling and maintenance. I find that using 10-12 drops of oil helps flush out the belt and sheave dust (crud) from the control sheave bearing. In fact, I believe in oiling the sheave in the FAST position, then operate the headstock by cycling from FAST to SLOW and back a few times. Then reoil the control sheave at the FAST position. I have not seen any effects from over oiling the control sheave bearing. The oil flushed out the control bearing even helps to some what lubricate the speed control worm gear and quadrant. Granted, this will collect sawdust and crud but believe the results still helps more than it hurts. Do not forget the motor Floating Sheave along with the shaft and key when oiling. course, these are my personal opinions from my experience rebuilding the headstocks, not Shopsmith recommendations.

billmayo · Post by **billmayo** » Wed Apr 03, 2013 9:38 am

These are the link belt instructions I have used for years. I never attempted to use the link belt backward so do not know if any ill effects will come from doing that.

[ATTACH]20805[/ATTACH]

I have not found any cheap V-belt that will operate on the Shopsmith without excessive vibration and/or noise. Most have slight width and depth changes where the belt is jointed together and these changes really do not like the sheave vanes as it passes over them. Do not try any Kevlar type V-belts as they are too stiff and really cause excessive noise on the sheaves. I operated a Kevlar V-belt for many hours trying to break it in but the excessive noise and vibration never went away. Alao it was very difficult to change the speed at the low and high end.

I strongly recommend buying the headstock belts from Shopsmith. My favorite Ebay seller, Gary, does have excellant Shopsmith parts and belts but believe Shopsmith is your best bet for belts.