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Speed Slowdown?
Posted: Tue Jul 31, 2012 10:52 pm
by mountain4don
I was running my 1981 vintage Shopsmith in drill press mode at top speed using a 3/8" router bit to drill some flat bottomed holes in a 3/4" piece of oak lumber. After a few holes the speed seemed to slow down and then not pick back up when I pulled the bit back out. I turned the motor off for a break and then when I started back up again it was still turning slow. When I turned the speed dial down it seemed to speed up a little momentarily and then decrease normally. When the motor is put under a heavy load can the belt slide down into the pullies to a slower speed and stay that way? Is my belt loose or is there some other problem?

Posted: Tue Jul 31, 2012 11:33 pm
by reible
mountain4don wrote:I was running my 1981 vintage Shopsmith in drill press mode at top speed using a 3/8" router bit to drill some flat bottomed holes in a 3/4" piece of oak lumber. After a few holes the speed seemed to slow down and then not pick back up when I pulled the bit back out. I turned the motor off for a break and then when I started back up again it was still turning slow. When I turned the speed dial down it seemed to speed up a little momentarily and then decrease normally. When the motor is put under a heavy load can the belt slide down into the pullies to a slower speed and stay that way? Is my belt loose or is there some other problem?

Is the router bit designed for plunge routing? It has been a while since I last used the shopsmith as a router but I don't recall any slow down when cutting. Since you are running at a third or less of the speed of a router the feed has to be slowed down a lot....
Ed
Posted: Wed Aug 01, 2012 2:17 am
by charlese
Sounds to me to be nothing serious. Just need a bit of lubrication for both motor sheave and control sheave. Then check the high speed adjustment. Assuming the drivebelt is still at proper width.
Posted: Wed Aug 01, 2012 11:49 am
by terrydowning
What Chuck said.
I had a similar experience, (Sawing not drilling) when lubricating I noticed the eccentric that controls drive belt tension came loose and was not adjusted properly anymore.
I reset the tension and made sure the eccentric was properly tightened, lubricated and performed a high speed adjustment. Working great since.
Eccentric out of adjustment?
Posted: Wed Aug 01, 2012 4:14 pm
by mountain4don
terrydowning wrote:What Chuck said.
I had a similar experience, (Sawing not drilling) when lubricating I noticed the eccentric that controls drive belt tension came loose and was not adjusted properly anymore.
I reset the tension and made sure the eccentric was properly tightened, lubricated and performed a high speed adjustment. Working great since.
Where might I find information on tightening or adjusting the eccentric? And how do I get to it? Where is it? I assume its on one of the belt pulley shafts? I have been using the Shopsmith pretty heavy for the last month or so and its really hot in the shop. So I should lubricate the sheeve shafts again anyway.
Posted: Wed Aug 01, 2012 4:47 pm
by dusty
mountain4don wrote:Where might I find information on tightening or adjusting the eccentric? And how do I get to it? Where is it? I assume its on one of the belt pulley shafts? I have been using the Shopsmith pretty heavy for the last month or so and its really hot in the shop. So I should lubricate the sheeve shafts again anyway.
I would suggest that you begin by viewing the
Sawdust Sessions. Several of them are very applicable to your questions.
Posted: Wed Aug 01, 2012 10:29 pm
by mountain4don
dusty wrote:I would suggest that you begin by viewing the
Sawdust Sessions. Several of them are very applicable to your questions.
Thank you very much. I didn't know about the "Sawdust" sessions. So now I need to go out to the shop tomorrow morning and check the polyvee belt tension and lube the speed adjusting sheeves. And tighten the belt up by rotating the eccentric if need be. And check the belts. I bet they are the original belts in the Shopsmith. Have to go check and see what a set cost.

Posted: Wed Aug 01, 2012 11:18 pm
by wa2crk
I just got a set. $53.78 total including shipping.
As of 7/23/12
Bill V