Mark VII “Project Machine”

[JPG]

May not fix 'your' problem, but I think it needs to be as pix above.

[shipwright]

Next time I’m in that part of the machine I’ll revisit that.

For now, I have everything back together and the motor no longer insists on blowing breakers.
….. however …… I have a few speed changer related issues. (I am at this point working with a “repaired” cam)

1) when the dial goes past about the stated “saw” speed moving up, the inner sheave half on the idler shaft comes off the key in the shaft. Am I missing a spacer behind the tube the follower bearing seats in?
2) there seems to be excessive vibration of the follower but the bearing seems okay to look at and wiggle.
3) in one direction the speed dial holds the speed (in the limited range I can play in with this cam) but in the other direction it wants to run away to high speed. (Can’t remember which)
4) the follower seems quite rough. I would have expected a very smooth surface with rounded edges. It actually seems to be trying to dig into the cam. Could this be a “home made” part?

My new printed cam should arrive soon so I will have more range to play with but something seems un-right in the setup besides just that.

[JPG]

1) By 'inner' sheave I assume that is the 'control' sheave? If it slips off the key, I think the key is short.

3) Creeping towards fast is caused by insufficient spring tension on the two bullet shaped 'detents'.

4) Is the follower correctly installed. It is NOT symmetrical. Backwards it tends to interfere with the cam. The roll pins may be dragging on the inner surface of the outer cam surface or they may be extending too far.

May help? viewtopic.php?p=140242#p140242

P.S. Realize the follower will shift(in/out) with different positioning of the eccentric(for poly-v belt tension). That must be provided for by adequate clearance between the pins and the cam.

[shipwright]

1) pretty sure the key goes all the way to the end but I’ll check. The sheave doesn’t fall off so it must be short.
3) creeping to fast (and it’s hardly “creeping”) is only in one direction and I think it’s a symptom of a bigger problem, perhaps related to the question I have for you at the end of the post
4) I’ve been all over that thread and made and found all the mistakes. ….. I think. The control shaft seems too short to have the eccentric gap at the 3:00 side so I’m pretty sure it needs to be on the 9:00 side (as you show it). I also had the follower upside down but it’s fixed now. Aside from checking the key length again (and if it is trapped or can move……) I don’t think there is much I can do until I have a better cam.
Now for the question.
I hate leftovers! Can you tell me where this goes? Is it in the whirring bits or the tightening and adjusting bits? There are only a few in the headstock and they are mostly other sizes. Can’t for the life of me remember where this one came from.

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[shipwright]

State of the Project:

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[JPG]

MAYBE HERE?

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Since the MVII runs both directions the M5 MANTRA towards 9:00 becomes moot. However I think the cam follower offset assumes the same direction.

[shipwright]

Damn! I’m pretty sure you’re right. I don’t remember putting one there. I was hoping it might be a factor in my vibration.
Thanks, easy fix.

[shipwright]

Found this in my pictures. Is this short enough to be trouble?
…and should the key way in the floating sheave be wider than the key? Mine is. It’s not worn, clean cut but wider than the key.

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[JPG]

Key and keyway 1/8"??? Control sheave keyway slop NOT desirable and causes noise and potential jamming. I do not think your length is an issue.

[shipwright]

Could I have a sheave half that doesn’t belong to this machine?