replacing lower Mark 5 belt with common automotive belt

[charlese]

This post is edited to protect the name of the good manufacturer: Goodyear - Not
Goodrich.

A while back (several years ago) SS substituted a Gates belt for the usual ones made by GOODYEAR. The reason at that time, was SS didn't want to place such a large order from GOODYEAR which Goodrich demanded.

I got in trouble when posting (on the Forum) how bad the Gates belts were, and suggest that bean counters should not effect the quality of Shopsmith parts. These postings were removed by Nick, but I think there are a few photos still on the forum.

The gates belts were not only narrower, but the splices were offset, giving a rough ride between sheaves.

Gates belts were not furnished by SS after a few months. They went back to the good ones.

[billmayo]

The Bandsawtirewarehouse motor belt is the correct width. I have used quite a few of them as replacements without any problems in setting the SLOW and FAST speeds to their proper RPMs. I found that the belts need to be operated for a few hours before making the final adjustment.

[JPG]

1/2 ". Realize they tend to increase wear on the sheaves.

Ideally a 9/16" belt is needed. A slight shift in speed range occurs with a belt narrower then 9/16". Ditto a length not = to 25.5".

Having spent some months getting(trying various lengths etc.) the correct belt for my Mark VII, I again recommend the mother ship(or a correct used one from e=bay).

Problem is, most '1/2"' belts are 12mm(less than 1/2") even though belt manufacturers state they are 13mm or more. They lie!!!!!!!!!

I am sure SS has to get a 'special' order to get the correct size. They tried 'typical' belts a while back with disastrous results. A few forum members can attest to that!

I think the Bandsawtirewarehouse belt on e-bay is 'correct'. 'HE' also makes a good poly-v belt FWIW.

Have you measured one to verify that it meets the specifications that you have applied? Or is this a blind endorsement?

I believe him after conversing with him. I have not heard anything negative about any of the stuff he has made.

[dusty]

The Bandsawtirewarehouse motor belt is the correct width. I have used quite a few of them as replacements without any problems in setting the SLOW and FAST speeds to their proper RPMs. I found that the belts need to be operated for a few hours before making the final adjustment.

I respect your opinion on these matters, Bill, but I am still confused.

What is the "correct" width for these belts? Is that width any different than the belts from Shopsmith?

How do you measure the length of the belt (ID or OD)? What is the correct length?

Who actually manufactures the belts for bandsawtirewarehouse? (rhetorical question)

[JPG]

A 'method' of measuring.

The belt is a used belt I purchased on e-bay. I know nothing of it's previous history.

The width varies around the belt(likely due to wear.)

width at the narrowest

504193 NARROW.jpg (560.82 KiB) Viewed 1873 times

And at the widest

504193 WIDE.jpg (855.4 KiB) Viewed 1873 times

As for the length, using the jointer base as a level surface:

Starting at the 'front' edge

504193 START.jpg (727.46 KiB) Viewed 1873 times

Starting mark after one full revolution held tight against the jointer bed

504193 STOP.jpg (574.88 KiB) Viewed 1873 times

504193 LENGTH.jpg (633.19 KiB) Viewed 1873 times

Focus not too good as the lighting was 'poor'(too many shadows etc.).

At least this is how I 'measure' em.

[beeg]

Well my unused one measured 17/32". I'll add the length later.

[JPG]

A while back (several years ago) SS substituted a Gates belt for the usual ones made by Goodrich. The reason at that time, was SS didn't want to place such a large order from Goodrich which Goodrich demanded.

I got in trouble when posting (on the Forum) how bad the Gates belts were, and suggest that bean counters should not effect the quality of Shopsmith parts. These postings were removed by Nick, but I think there are a few photos still on the forum.

The gates belts were not only narrower, but the splices were offset, giving a rough ride between sheaves.

Gates belts were not furnished by SS after a few months. They went back to the good ones.

Oh I do remember that!

FWIW if a belt has a crown(roundish top, not flat), do not use.

I would have thought Nick would 'know' better. Most likely deleted under 'direction'.

I never had one from SS, but do recall them in the auto stores. POC IMHO.

[dusty]

I'm trying to better understand the mechanical actions of the variable sheaves.

At low speed (with the top of the belt level with the edge of the upper sheave) what is the distance from the edge of the of the sheave to the top of the belt on the lower sheave? Knowing this allows one to calculate the effective pulley diameter of the lower sheave.

Whatever the answer is, I would expect it to be the same on the upper sheave after changing to high speed.

Furthermore: At low speed, the top of the motor belt is level with the outer edge of the upper sheave. When I change to high speed, I would have expected the same relationship between the top of the motor belt and the outer edge of the lower sheave. That is not the case. There is about 3/16" difference (the belt being below the edge of the sheave).

Is there a logical reason for these anomalies?

[jsburger]

I'm trying to better understand the mechanical actions of the variable sheaves.

At low speed (with the top of the belt level with the edge of the upper sheave) what is the distance from the edge of the of the sheave to the top of the belt on the lower sheave? Knowing this allows one to calculate the effective pulley diameter of the lower sheave.

Whatever the answer is, I would expect it to be the same on the upper sheave after changing to high speed.

Furthermore: At low speed, the top of the motor belt is level with the outer edge of the upper sheave. When I change to high speed, I would have expected the same relationship between the top of the motor belt and the outer edge of the lower sheave. That is not the case. There is about 3/8" difference (the belt being below the edge of the sheave).

Is there a logical reason for these anomalies?

Are the upper and lower sheaves the same diameter and is the angle of the upper and lower sheaves the same? Both a difference in the diameter or the angle will create what you are observing will it not?

The 10ER speed change has the same diameter sheaves and the same angle (I believe). Of course they are all mounted on the same shaft. A double sheave in the center and a single sheave on each side. They are left and right not top and bottom. From high to low both belts ride the same distance from the edge of the sheaves.

[dusty]

The sheaves are all the same diameter. When you ask about the angle, I am assuming you mean the face of the sheave where the belt rides. Yes, they are all "pitched at the same angle.

I think they would have to be because they interface with the edge of the same belt.