Speed Control Issue

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KCollins
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Speed Control Issue

Post by KCollins »

Okay... Bought my saw a few months ago. Cleaned it. Lubed it. Ran smooth and adjusted speeds easily. When I was finished with it I turned it down to slow. Then life got in the way and didn't get to actually use it until today. I set it up for the table saw and hit the on switch. I started to increase the speed and it suddenly clicked and skipped twice right in a row and then it turned freely but the speed didn't increase as it turned. When I returned it to slow the outer indicator dial still rotates but the speed does not change. I opened the other side and looked in and the arm is still attached with the wire loop on the end of the shive wheel. I checked the handle dial and the set screw is seated in the right place. No idea what has happened but SOMETHING has definitely happened. LOL.... It was cold out too.. Around 32 degrees. Are Shopsmiths sensitive to the cold?

Suggestions guys? Where to even begin.

Kevin
Kevin Collins

1x Mark 7 - 520
2x Mark 5 - 510
1x 1956 Mark 5 - 500 in need of restoration
DLB
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Re: Speed Control Issue

Post by DLB »

Can you take a picture through the inspection hole and post it? Likely things to look for: Does the worm gear turn in response to the speed control? (Probably yes, you said the set screw was still correct.) Is the 'pork chop' (speed control quadrant) centered on the worm gear and is it moving in response to the control? (Highest failure item in a Shopsmith, I'm told.) Are the legs that hold the pork chop straight and with minimal gaps where the roll pin that the quadrant rotates on goes through them? (This would be the likely cause if the quadrant is not centered/straight relative to the worm gear.) Finally, is the button bearing in the control sheave intact? This is where that wire retaining loop connects the speed control to the control sheave.

As long as the internals are on slow, you should have a reasonably good view of those parts. As a precaution, always unplug the machine before putting your hand inside that inspection hole.

- David
KCollins
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Re: Speed Control Issue

Post by KCollins »

Hope these show you what you need to see.
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IMG_2540 Reduced.png (1.4 MiB) Viewed 1909 times
Kevin Collins

1x Mark 7 - 520
2x Mark 5 - 510
1x 1956 Mark 5 - 500 in need of restoration
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reible
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Re: Speed Control Issue

Post by reible »

The red disk that you turn has gears inside, most likely they are no more. There is a person on ebay who does a replacement for a decent price. You send him yours and he sends you a repaired one, or you can have yours repaired but the turn around is longer.

Yes this happens and not only in cold weather. I once lubed my parts with bee's wax as a former expert recommended, at 32 degrees it is as hard as a rock and I had to chisel it off to use my shopsmith......... Had I forced it I too would have had to replace the part.

Ed
{Knight of the Shopsmith} [Hero's don't wear capes, they wear dog tags]
DLB
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Re: Speed Control Issue

Post by DLB »

I don't see anything obviously wrong on the speed control. Are you sure the setscrew for the speed handle is tight? There should be a recess in the shaft and the setscrew should screw down into that recess. That ensures the worm gear turns when you turn the handle. I see some spots on the quadrant (pork chop) that looks like wear, but it could just be the absence of sawdust where that part had been engaged. Quadrant looks centered and straight, and the leg we can see looks good.

If it was me I would run the motor and watch through the inspection port while increasing the speed one or two turns. You should see the worm gear turning CCW at the same rate you're turning the handle, the end of the quadrant moving to the left, and the control sheave following it to the left. If all of that is happening the speed control would seem to be working. The next step I would take is slide the belt cover off and see if the sheaves are moving in response to the speed control.

One thing to keep in mind is that speed and sound don't change very quickly at the slow speeds.

I also recommend routing those power wires away from moving parts and/or add some chaffing protection. It might be the pics, but they look very close to the wedge lock screw and to the way tubes.

- David
KCollins
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Re: Speed Control Issue

Post by KCollins »

So I turned it on and turned the dial. Sure enough once the worm gear moved the porkchop over some it was very apparent the hoop has disconnected from the sheave. So it is colder than a witches tit out there tonight so I'm not going to work on it now but is it as easy as reattaching that hoop and moving on with my day or is that one broken and I need a new one?
Kevin Collins

1x Mark 7 - 520
2x Mark 5 - 510
1x 1956 Mark 5 - 500 in need of restoration
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rpd
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Re: Speed Control Issue

Post by rpd »

If the hoop comes off the button bearing, it is usually because the bearing seized up.
Ron Dyck
==================================================================
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KCollins
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Re: Speed Control Issue

Post by KCollins »

Well it was cold and it was working fine back in July when I cleaned and oiled everything. So how do I un-seize the bearing?
Kevin Collins

1x Mark 7 - 520
2x Mark 5 - 510
1x 1956 Mark 5 - 500 in need of restoration
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dusty
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Re: Speed Control Issue

Post by dusty »

KCollins wrote: Tue Nov 17, 2020 8:05 am Well it was cold and it was working fine back in July when I cleaned and oiled everything. So how do I un-seize the bearing?
I have no recommendation for how to "unseize" a bearing but would you really want to use a bearing that you knew had seized? I would not!
"Making Sawdust Safely"
Dusty
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DLB
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Re: Speed Control Issue

Post by DLB »

Based on the first post, it sounds like in this case the loop might have pulled out of the bearing while trying to adjust speed, therefore maybe not seized.(?) If not seized, the problem is more likely related to how freely the Control Sheave on the Idler and the Floating Sheave on the motor shaft move. The speed control system puts some pressure on the Control Sheave in the 'faster' direction. If there is resistance to the sheaves moving then the speed control is trying to pull the Control Sheave as opposed to just letting it move. If there is too much resistance the loop can pull out of the 'button.'

I would start by adjusting the speed control out of the way or removing it to see if the bearing is seized. The button should spin inside the Control Sheave.

- David
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