Noise vibration problems/suspected drive belt

[bing5]

In the process of reconditioning and cutting down a maltreated mark V clone into a mini for dedicated sanding shaping to compliment my standard Mark V Shopsmith. Noticed she is pretty noisy and more vibration than average. I have taken the motor housing off to examine the belts while she runs and there seems to be quite a bit of slack in the drive belt and when running the belt seems to be causing the noise vibration. Is it possible that the belt is the incorrect size? Can the drive belt be tensioned? Or is it time to replace the belt?

Have looked to some previous posts regarding vibration problems and belt tenting but most did not relate to the main drive belt?

Appreciate any advice

[JPG]

To me there is 'motor' belt and either a gilmer or a poly-v drive belt.

The gilmer/poly-v belts are tensioned by rotating the idler shaft eccentric.

The tension for the motor belt is automatically provided by the floating sheave on the motor pulley. Proper operation of the floating sheave requires adequate lubrication between the floating sheave and the motor shaft.

The motor belt absolutely needs to be obtained from the mother ship. 26.5" x 17/32".


Now if it is a clone, all bets are off. We need pix to understand(hopefully) what we are dealing with.

[bing5]

Seems identical as far as I can tell. Poly v belt is very tight and eccentric bushing is as loose as it can be with the slot for adjustment facing down in the centre.

The motor belt seems pretty slack when the variable speed is set at slow/stationary, and some motor belt vibration is visible when running at any speed (have removed the saw arbor/blade to isolate that as a contributor -problem persists.

Motor belt reads: B1 continental 13x630/A 25/A 660 EL

Poly v belt reads:Optibelt RB J362 D1

Thanks for your advice, much appreciated.

Best,

Gidon.

[charlese]

A while back Shopsmith ran out of drive belts from Goodyear and bought some from Gates. These belts came with a bit of offset where the joint is made. This made the sides of the belt rough at that point and caused vibration.

It is probably worth your time to remove the belt and check the smoothness of it's sides.

[JPG]

Seems identical as far as I can tell. Poly v belt is very tight and eccentric bushing is as loose as it can be with the slot for adjustment facing down in the centre.

The motor belt seems pretty slack when the variable speed is set at slow/stationary, and some motor belt vibration is visible when running at any speed (have removed the saw arbor/blade to isolate that as a contributor -problem persists.

Motor belt reads: B1 continental 13x630/A 25/A 660 EL

Poly v belt reads:Optibelt RB J362 D1

Thanks for your advice, much appreciated.

Best,

Gidon.

I take it all 4 pix were taken with the speed control knob at slow.

Some pix of the interior showing the mechanism that I assume moves what appears similar to the SS idler pulley would preclude incorrect assumptions on my part.

The most apparent strange situation is the floating sheave on the motor shaft. It appears nearly wide open. I am suspicious of the idler sheave being stuck open as well. That would explain the grossly slack motor belt.

Both movable sheaves may be stuck.

Interesting clone!


Second looks! The eccentric is proud of the casting. Assuming it was intended to be 'like' a SS, that would cause the idler sheave to possibly be too far away from the control sheave(clone variation may negate/cause that). I do not know what positions the idler sheave along the idler shaft. That motor belt would be too short on a M5. The motor may be positioned differently though.

[bing5]

Yes all four were taken with the speed control knob at slow. Attached some more pics of the sheaves and eccentric bushing.

Thanks for giving this a look.

[JPG]

A pix taken through the access hole will be helpful. It appears the mechanism that moves the control sheave is different from a SS.

The motor belt does not look slack in these pix???