Shopsmith Forums

hammerforce wrote:Reviving an old thread here...

I am the proud owner of a ...Mark 6? Long story short it is a Mark VII 'body' with the top half of a Mark V headstock attached to the bottom half of the Mark VII (still has reverse). I still have a lot of the 7's spare parts, including the cam-less speed control, so I suspect this was a previous owner's solution to a broken cam.

It came along with all the original advertising materials, manuals and parts list, if anyone doesn't have the info and needs it, I can scan it.

My question is, did anyone come up with a replacement belt analogue we can find at a car parts store?

I need to replace the main belt, part 507490

The first two posts are instructive.

http://www.shopsmith.com/ss_forum/viewtopic.php?t=13906

First determine the motor/idler shaft spacing on your 'mixture'.

Then calculate the belt length. If you follow the entire thread you will discover a reasonable priced belt available in 1/2" increments. Also a way to determine if length is correct(belt position on pulleys at speed extremes).

If you do not mind, share with us the idler shaft/motor shaft spacing on your 'mixtutre'.

Thank you Bill and JPG. I ended up picking up a 30" belt yesterday from a local auto parts store and getting it on. With the adjustable sheaves, this should only alter the speeds in comparison to the listed speeds on the controller, correct? My speed controller's handle is partially stripped so the readout is wrong regardless for now. I see they are still available for cheap new so I'll have to replace it, as I'd rather not have to judge by ear.

I bought this from a guy who apparently was using it, though possible not for a couple years, as I had to pull the motor off and blow it out to get it to start and turn.

It still blows the breaker if I run it in reverse. Any thoughts? All wiring is up to snuff per the Mark VII Parts Manual diagram with an A.O. Smith motor.

Now the good stuff... Pictures!

JPG wrote:
If you do not mind, share with us the idler shaft/motor shaft spacing on your 'mixtutre'.

I will have to check it out tonight!

If that is a green wire from the power cord wound around the leftmost "5" terminal, it should be connected to the MOTOR frame.

There should only be the "5" to "5" jumper and a wire going to the "5" terminal on the start relay. Relay "5" terminal also has the yellow motor wire connected.
All the other wires appear connected correctly.
P.S. You are missing the lamp.

P.P.S That is I believe a tapped hole in the motor frame directly below that "5" terminal. The ground wire belongs there.

Thanks, the ground was a question mark for me, it isn't on the actual terminal, but still not properly grounded as you can see in this picture from a different angle. Any thoughts on the reverse blowing the breaker? Think this could be related?

Thank you for the response, very glad I found a resource like you guys

JPG wrote:
P.P.S That is I believe a tapped hole in the motor frame directly below that "5" terminal. The ground wire belongs there.

I'll move it over this evening, good eye!

hammerforce wrote:Thanks, the ground was a question mark for me, it isn't on the actual terminal, but still not properly grounded as you can see in this picture from a different angle. Any thoughts on the reverse blowing the breaker? Think this could be related?

Thank you for the response, very glad I found a resource like you guys

No. The ground wire there should not cause reverse problem.


Is the motor humming prior to the breaker tripping?(do not do often/repeatedly).


If so the start winding is not being switched for reverse. To verify that,
(only activate rev in the steps below!!!!!!!)

Do the following ONLY if the motor does hum prior to tripping breaker in reverse.

Unplug power cord.

Activate REV switch.

Jumper terminals T9 and 5.

BRIEFLY insert power plug.

If it starts, the switch is not closing terminals T9 to 5(outer).STOP

If it just hums, unplug the power cord.

Jumper terminals T5 and 2.

Again briefly insert power plug.

If it starts, the switch is not closing terminals T5 to 2.

Unplug power cord.

Remove the jumper between terminals T9 and 5.

Again briefly insert power plug.

If it runs, only the T5 to 2 switching is defective.(failing to 'make')

If it only hums, both the T5 to 2 AND the T9 to 5 switching are defective.

Remove ALL added jumpers.

If you are adventuresome, the switch can be taken apart to determine/correct(maybe) reason for failing.


Make sure you understand the jumpering above(it takes the place of the switch making contact).

REPEAT Only do this with the switch set to REV and if the motor hums!!!

"Briefly" means not long enough for the breaker to trip, but long enough to determine the motor either hums or starts. If it only hums it is very important to make "brief" as short as possible.

If you want to sell the plastic speed control cam, pls let me know. Mine
went bad this past week.

Do you want to sell the plastic cam now that you have a metal one?

lwmccord wrote:Do you want to sell the plastic cam now that you have a metal one?

I do not now nor ever had a plastic MVII speed control cam.