headstock problems

tgreen · Post by **tgreen** » Tue Feb 13, 2007 1:46 pm

My shopsmith is twenty seven years old and I tightened the eccentric bushing a little to tight and snapped off the piece the bolt goes through. (do not over tighten). Can this piece be welded or reattached in some way? I ordered a new headstock and it runs a lot quieter than the old one. I have a few other parts to replace but wanted to know if it could be repaired first.

billmayo · Post by **billmayo** » Tue Feb 13, 2007 8:35 pm

I had several empty headstock housings with broken "ears". I was able to find a really good Shopsmith owner with a shop that does lathe work and aluminum aircraft welding for a living. He cut the broken piece so he had a V for the weld. I used a few washers (took a few tries) between the ears and a tight bolt to hold the broken ear in the original position. I used the eccentric bushing to test the fit. He preheated and tig welded on the outside of the broken ear and housing taking breaks to prevent overheating. He did not weld any on the inside of the bushing housing. I took a curved file and removed the tiny bit of welding that came inside. It was a really nice job and someone to know. I was only charged $25.00 per housing. I am using the 2 headstocks for my own use, not for resale, with no problem tightening the Poly-V belt.

Shopsmith Instructions 521681 - Replacement of the Poly V or Gilmer Belt has this caution "DO NOT overtighten clamp bolt. This will break the ears on the casting. Use no more than 20 in./lbs. torque.".

I have an in/pd torque wrench but never used it on the Shopsmith. The 1/4" allen wrench I used has a 1" L to it. I just turned the clamp bolt as tight with my hand as the 1" allowed. If my math is OK, this means I only needed to put 20 pds. pressure at the tip of the L part of the allen wrench. Checking a couple of my headstocks I actually had 25-30 in/pds of torque on the clamp bolt. I found a good check is to put the lock washer ends where you can see them. Just when the lockwasher flatten out, that was 20 in/pds on the torque wrench. I had one of the eccentric bushings slide into the headstock after operating and changing speeds for several hours. Now, Shopsmith uses an eccentric bushing with a small ridge on the outside that prevents this problem. When using the older solid bushing, I went back to 25-30 in/pds and use the 20 in/pds for the new bushing.

The above instructions came with the Poly-V belt. I really appreciate it when Shopsmith includes instructions for replacing the part ordered. I do read these before replacing the part. I was replacing both belts for a customer because both belts were frayed on the edges. When turning the idler shaft, there was a noise (bump) each rotation. The eccentric bushing was one that has an opening (slot) at the thin part. The eccentric bushing setscrew was really torqued tight. This may have deformed the bearing race according to the above instruction. The clamp bolt must have had at least 20-25 ft/pds of torque on it but no broken ear. After replacing the belts and hand tighting the clamp bolt, the idler shaft was running a lot warmer than normal. I replace the slotted eccentric bushing with a solid one, lightly tighten the set screw and actually torqued the clamp bolt to 25 in/pds after setting the belt tension, then everything was normal temperature.

Bill Mayo billstoolz.com

tgreen wrote:My shopsmith is twenty seven years old and I tightened the eccentric bushing a little to tight and snapped off the piece the bolt goes through. (do not over tighten). Can this piece be welded or reattached in some way? I ordered a new headstock and it runs a lot quieter than the old one. I have a few other parts to replace but wanted to know if it could be repaired first.

eldyfig · Post by **eldyfig** » Sun Jun 08, 2008 4:12 pm

About the eccentric bushing:

Bill (or anyone who knows), is the solid bushing that you mention above, is it what SS ships if I were to order one now? Is it the new version?

I think I may be running into exactly what your customer may have had. My aux. spindles are warm. Never noticed it too much in saw mode. But, since it has been it drill press mode, I have definitely noticed the heat. I am figuring that when I saw, I make my cut and turn the SS back off, it cools off. However, in drill press mode, the SS runs longer since I am drilling multiple holes. Heat keeps building. It got to the point where the upper spindle was warm, the lower spindle was warmer, and the headstock itself was actually getting warm I don't think the clamp bolt is too tight. It could be possible the bushing setscrew is. I am about to go check it out. The headstock is open right now. I just did maintenance on it two months ago. I have been known to over tighten things.

What about the screw and washer above the bushing (at the 12 o'clock position)?. It looks like it holds the bushing in. What is the deal on it? Can that be too tight?

billmayo · Post by **billmayo** » Sun Jun 08, 2008 9:38 pm

First, The headstock housing is aluminum so normal tightening is all that is needed as overtightening will strip screw threads or break something. I have to use steel inserts where someone thought more is better.

The last eccentric bushing I ordered was the latest one that I know about. There has been many different versions of the eccentric bushing. Over tightening the set screw can be felt and sometimes heared when turning the idler shaft. If your headstock is only getting fairly warm after operating for a time, I do not believe there is anything wrong with it. I find listening and feeling the headstock as you change speed can help determine any unusal noises/sounds/vibrations. The clamp bolt will only cause problems if you are using a split eccentric bushing. If it is a solid bushing, then the most that can happen is breaking an ear off the housing when over tightening.

All my Shopsmith headstocks gets hot after hard use. As long as I can hold my finger on the housing for a couple seconds, I don't worry about it. If it feels like you will get burned when you touch the housing, then it is too hot and needs to be checked. With no load when operating for a while, then the housing will get fairly warm at HIGH speed. It should not be hot. I find that belt tension and alignment (a problem on Gilmer drives) also can cause heat problems.

The screw and washer above the eccentric bushing is a safety device to me. I use a larger body washer so the eccentric bushing or the idler shaft can not come out that way when operating if the set screw or clamp bolt vibrates loose. I just use a regular phillips screwdrive to tighten the screw until the washer is againest the housing.

eldyfig wrote:About the eccentric bushing:

Bill (or anyone who knows), is the solid bushing that you mention above, is it what SS ships if I were to order one now? Is it the new version?

I think I may be running into exactly what your customer may have had. My aux. spindles are warm. Never noticed it too much in saw mode. But, since it has been it drill press mode, I have definitely noticed the heat. I am figuring that when I saw, I make my cut and turn the SS back off, it cools off. However, in drill press mode, the SS runs longer since I am drilling multiple holes. Heat keeps building. It got to the point where the upper spindle was warm, the lower spindle was warmer, and the headstock itself was actually getting warm I don't think the clamp bolt is too tight. It could be possible the bushing setscrew is. I am about to go check it out. The headstock is open right now. I just did maintenance on it two months ago. I have been known to over tighten things.

What about the screw and washer above the bushing (at the 12 o'clock position)?. It looks like it holds the bushing in. What is the deal on it? Can that be too tight?

eldyfig · Post by **eldyfig** » Mon Jun 09, 2008 2:15 am

I went back out this evening and dropped a couple more drops of oil in the sheaves. Reset the v-belt tension. Did some thorough cleaning and maintenance in the headstock then tried it out. The housing didn't get unreasonably warm after all my testing. The upper spindle doesn't seem to be warming up. The idler spindle still is. I wonder if maybe it is normal? Honestly, never noticed before. It isn't so hot I can't touch it. I can clamp my hand to it. It just get a little hotter than warm. How warm should it get?

The eccentric bushing I have is the one with the split. (How do you adjust the solid bushing if there isn't a split?) The set screw is just snug with a 1/4" nut driver. When I turn the shaft, all is smooth, no rubbing. The clamp bolt is snug with a T handle hex wrench.

Earlier, I thought I had excessive noise in the quill area, especially at low speed. I don't have it anymore. Maybe the extra clean up fixed it. Maybe I just needed a break.

charlese · Post by **charlese** » Mon Jun 09, 2008 2:19 am

billmayo wrote:...
The last eccentric bushing I ordered was the latest one that I know about. There has been many different versions of the eccentric bushing. Over tightening the set set can be felt and sometimes heared when turning the idler shaft. If your headstock is only getting fairly warm after operating for a time, I do not believe there is anything wrong with it. I find listening and feeling the headstock as you change speed can help determine any unusual noises/sounds/vibrations. The clamp bolt will only cause problems if you are using a split eccentric bushing. If it is a solid bushing, them the most that can happen is breaking an ear off the housing when over tightening.

All my Shopsmith headstocks gets hot after hard use. As long as I can hold my finger on the housing for a couple seconds, I don't worry about it. If it feels like you will get burned when you touch the housing, then it is too hot and needs to be checked. With no load when operating for a while, then the housing will get fairly warm at HIGH speed. It should not be hot. I find that belt tension and alignment (a problem on Gilmer drives) also can cause heat problems.

The screw and washer above the eccentric bushing is a safety device to me. I use a larger body washer so the eccentric bushing or the idler shaft can not come out that way when operating if the set screw or clamp bolt vibrates loose. I just use a regular phillips screwdriver to tighten the screw until the washer is against the housing.

Hi Tony! Bill knows! Just wanted to say I agree 100% with the heat thing. In fact I was told by one of the gals at SS the lower hub also acts as a heat sink. Once, after I snapped off the little washered screw, I was told its purpose is to prevent inward movement of the eccentric. It has been replaced.

eldyfig · Post by **eldyfig** » Mon Jun 09, 2008 2:29 am

Hi Chuck. Yes, Bill has been a great help. Too bad he lives in South Florida and not North Florida. (I am only 2/3rds of a mile across the state line).

billmayo · Post by **billmayo** » Mon Jun 09, 2008 10:28 am

If everyone would take the time to clean and lubricate their headstock and check the belt tension after a few day of hard use, I would never get any headstocks to repair. Of course, when to do this task is an area that noone seems to have any firm guidelines. They vary from once a year to every 10 hours of operation.

I brought some hour meters to fit in a mounting that I made to fit in place of the logo cover for my Shopsmiths. I would hope that Shopsmith will include an hour meter and tach if they upgrade their headstock in the future.

I am an hour from the Orlando theme parks and an hour from the gulf coast beaches. Take a couple days of vacation and drop by. We like to think we are part of the Central Florida corridor.

a1gutterman · Post by **a1gutterman** » Mon Jun 09, 2008 7:39 pm

billmayo wrote:.........I am an hour from the Orlando theme parks and an hour from the gulf coast beaches. Take a couple days of vacation and drop by. We like to think we are part of the Central Florida corridor.

Thanks for the invitation, Bill! If ever I am near, I will take you up on that!:D

charlese · Post by **charlese** » Mon Jun 09, 2008 10:33 pm

If we ever get down that way we will be sure to give you a ring! Thanks!

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