Shopsmith Mark VII with Mark V speed control

[n240sxle91]

Yes, I agree I need a new key one way or another. I plan on ordering it tomorrow. Mine looks like trash.

Your idea of making the 'snout' longer by using the copper sleeve is brilliant! That actually could be the final touch to make the conversion work.

One way we might be able to find the correct length the 'snout' should be is to measure on a Mark V the distance from where the snout abuts on the control sheave to where it meets the quadrant assembly at a known location (HIGH or LOW). It would be easier to make the measurement with the belt off, so we know the sheaves are fully closed.

Unfortunately, I already put the sleeve on my control sheave. I might be able to carefully use the dremel tool to cut it off. However, even if I did that I don't have the proper tools, or knowhow, to secure the bearing at the end of the new snout. That would take someone with some metal working experience to do that. That's out of my wheelhouse.

I'm now torn on what to do. I believe your idea on how to lengthen the snout is a viable one, and it could work. However, I'm also thinking that converting back to a Mark VII speed control would for sure solve my issues.

I almost forgot, you asked about my control sheave. The snout measured 1.25" tall without the button, and 1.5" with the button.

220170423_212351.jpg (155.07 KiB) Viewed 9942 times

[JPG]

That IS a MV control sheave. The MVII is 1/4" shorter.

BTW the MV key is about 1/4" shorter than the shaft.

[n240sxle91]

That's good to know. The next step would be to find on a Mark V the correct distance from the Mark V control sheave fully pressed against the idler sheave (without belt) to a known position on the quadrant assembly. I could then adjust my control sheave's snout length to get that same distance (assuming I could find a way to lengthen the snout).

Does that make any sense? It makes sense in my head, but it's late and it might look like nonsense when I get up in the morning.

[n240sxle91]

FYI I believe the Mark V and Mark VII Key are the same part. They have the same part# from Shopsmith.

I am still unsure which way I should go. I think if I could find the parts needed to go back to the Mark VII speed control I would. In the back of my head I've always liked the idea of restoring my Mark VII back to the way it was anyway.

I did think of one way I might be able to extend the snout on a MV control sheave. Using JPG's idea on the sleeve, what if I took a MV control sheave and cut the 'snout' off in the middle with a hacksaw. I could then use a 3/4" copper pipe as a fill in to extend it to the proper distance (still an unknown), and a 3/4" copper coupler to connect it all together. I believe the extension will only be somewhere between 1/4"-3/4", so the copper pipe/coupler wouldn't have to support a long distance. Any thoughts on this idea?

[n240sxle91]

FYI I believe the Mark V and Mark VII Key are the same part. They have the same part# from Shopsmith.

EDIT:
I believe extending the 'snout' on the MV control sheave is actually not too difficult to do. I believe JPG is right in that using the sleeve it's possible to do. My thought is cutting half of the 'snout' off. Then use a 3/4" copper pipe as the extension, and a 3/4" copper coupler as the connection/sleeve. The pipe with the coupler will help strengthen the extension.

That being said I believe that only fixes half of the problem. I believe the quadrant assembly is too short. Even if the 'snout' is longer the button rides on the end of the quadrant assembly. Maybe that isn't really an issue, but it seems like it puts lateral pressure on the control sheave right now. I think that is why it is prone to binding up. This could be fixed by someone with a CNC machine. They could recreate the assembly, but make it 1/2"-3/4" longer. I think that would be the final piece to the puzzle.

For now I'm going to start the difficult process of getting the parts needed to go back to a MVII speed control.

[JPG]

That will allow time to figger out a Mark V 'solution'.

I am all for you reverting back to original, but that will not be either easy nor quick(unless you get very lucky-listening DB5?).

[n240sxle91]

Lucky-listening DB5?

[JPG]

Lucky-listening DB5?

May be wishful 'thinking'. Explain later.

[n240sxle91]

It's probably a long shot, but hopefully someone on here, or maybe ebay, will be getting rid of their MVII and I can get it then.

[n240sxle91]

So, I took a couple days off from the whole thing to try to clear my head. I'm still actively looking for the Mark VII speed control parts, but I realize that will take some time. So, in the mean time I'll continue to work on the conversion problems.

With the belt off I played around with the control sheave movement today. I noticed that even with the belt off that it is jamming up when I am going from HIGH to SLOW speed. However, it does not jam up going from MEDIUM speed to SLOW speed. So, it dawned on me that maybe the MV speed control is pulling the control sheave out too far. Maybe the MVII doesn't get pulled out as far.

SO, to anyone with a Mark VII out there could you please measure the distance between the outside edge of the control sheave and the idler sheave when the speed is set to HIGH? I can then use that measurement to check where my control sheave should be at high. This would be a HUGE help!

I've also come up with another fix. I can set the Mark V max speed set screw so it limits the max speed before getting to the "point of no return". Doing this removes the problem of accidentally putting the control sheave out too far and jamming it up.

Looking forward to getting the distance measurement on the control/idler sheaves!

Thanks!