New member, not sure where to start.

[miken]

Yes, thank you. The spacer must be stuck in there. I thought the eccentric was machined to accept the bearing. Never considered it was a spacer.
I also found it odd that the sheave closest to the eccentric floats free on the shaft. I was expecting a set screw like in the ribbed pulley above it. With the outer pulley pushing against it the only thing holding it is belt tension?

[JPG]

Yes! IIRC

[miken]

So I have been cleaning up the Mark VII over the last few weeks and it went pretty well. It's all back together and it starts and runs better than I ever remember. I was looking through one of my dad's old tool boxes and found another complete switch. He must have been saving it, as it is in much better condition than the one in the machine. Still, I decided to better repair the old switch and run it as long as it lasts. I even found the replacement light bulbs at HD (just like JPG said in another post I read). It now works properly including power to L1 and L2, forward and reverse, with key safety. I also replaced the old stiff power cord. I decided not to install the vacuum for now.

switches.jpg (45.98 KiB) Viewed 1403 times

I have few questions I hope someone can answer;
1. does anyone know how the little spring goes back into the headstock pinion drive crank handle? See picture.

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2. I am not sure the square nut belongs on the shaft next to the eccentric? Does anyone else have this square nut?

ecentric.jpg (37.04 KiB) Viewed 1403 times

3. how tight is the nut on the eccentric supposed to be? I know it is just tightening against the circlip on the opposite side of the eccentric so I imagine it should not be torqued to much.

I am pretty sure I forgot to retighten the set screw in the eccentric that is holding that spacer between the bearings, so I guess I will be disassembling it again. Thanks for all info I have received from this website, greatly appreciate it.

motor and switch.jpg (45.12 KiB) Viewed 1403 times

table.jpg (53.28 KiB) Viewed 1403 times

Sorry, all my pictures rotated.

[JPG]

Oh! You HAVE the little spring! IIRC the small end goes into the small hole in the shaft and the large radius end lays against a similarly shaped surface. I have never understood the reason for that spring.(mine originally did not have it)

The idler shaft need only be snugged to eliminate play. The square thingie is furrrun. The lock tabs prevent the loosely tightened nut from backing out.

I do not think fully tightening the spacer set screw is critical.

BTW I recommend the eccentric being rotated from 0600 towards 0900 rather than CCW to 0300 as you have done so. Running torque will have a tendency to move the eccentric CW.

Glad you have the power switch functioning correctly! You are fortunate to have a spare.

[miken]

Yes, I have the spring! But I would need a picture to figure out how to get it back in there. I am not worried about it. I think it is supposed to stop the crank from rattling. Thanks for trying to explain it to me.

The switch was a challenge, but it is working really well for now.

When I tried rotating the eccentric in the opposite direction it appeared to make the shaft end bind against the plastic speed cam. I will try again now that it is all together. Will give me an opportunity to see if I can reach that set screw without completely disassembling the whole thing. I think the spacer is frozen in there anyway, but it will dog me if I don't try.

Regarding the square nut, what do you mean by "furrrun"?

Also, my Mark VII does not have the casters, and I really want them. Do you think it's possible to retrofit a set of 510 casters if I fabricate the part below? Are the cams, rods, foot pedals, etc. the same? I see several sets of 510 casters available on ebay.

Casters.PNG (96.16 KiB) Viewed 1391 times

Thanks, Mike -

[JPG]

The caster assembly is an entirely different design that is incorporated into the base. Item "7" above tends to break. There is more than one design version. I dislike "5" above.

furrun is hillbilly speak fer foreign.

I think you can improve upon both 6 and 7.

IIRC the stem length on "12" is shorter.

Then there is that weird foot pedal.

Not sure installing that spring is possible with the assembly 'assembled'.

[miken]

Furrun, Hillbilly, funny. I am pretty sure the square nut was added so the front nut could be used as a jam nut and tighten against it. The inside piece of that special washer that keeps that nut from backing off, the part that fits into the keyway is gone. It probably kept loosening up and that was a quick fix.

The good news ; you can easily pull the shaft to check that set screw in the eccentric. It was tight, . . sigh.
In fact, you can pretty easily remove the entire back sheave that is connected to the cam follower.

The bad news ; the cam follower is touching the sides of the plastic speed cam in either direction I turn the eccentric. This can only mean one thing, the belt is stretched, and the eccentric needs to rotate further than it really should to get proper tension on the belt. This means the whole thing is coming back off. The belt says MAGNA on it and I am pretty sure it is original. Can you tell me the best place to get belts and the model numbers please?

Finally, the cam follower itself is beveled on the part that touches the speed cam. Does it matter which direction that bevel is?

Thanks JPG, appreciate your sticking with me here.
Mike -

[JPG]

Yes the cam follower 'bevel' orientation matters.

My memory is shakey here, but it might affect the 'in/out' positioning as well.

The taper needs to mate with the slope of the cam. It should be installed so the bevel edge that provides the greater clearance to the cam is towards the cam profile where it increases in diameter.

[miken]

Yes, it is very hard to tell, I tried it both ways. It seemed to me that when the bevel was facing one way the sharp point of the bevel was very close to the speed cam when fully rotated to high speed, and when it was the other way (180 degrees opposite) the sharp point of the bevel was very close the speed cam when it was in low speed. Thus I am questioning. It didn't appear to matter, but of course it must. I need to noodle through your description some more.

As far as it affecting the in/out, the shaft appears to be centered on the follower, so when I flip the follower 180 degrees it just contacts the opposite side of the speed cam as you would expect.

I found this in another post for the motor belt; D&D PowerDrive A27.5/4L295 V Belt, A/4L, Rubber, 1/2" x 29.5" OC Is this still the consensus?
Still looking for the ribbed belt replacement number. . .

[JPG]

29.5 I THINK SO.
https://www.ebay.com/itm/MAGNA-AMERICAN ... SwLN5WlyeK

Ignore that 2 HP bs.