[BarnBurner]

I recently cooked a belt on my mill, ordered replacements from Tormach. After replacing and using for less than 2 hours, it is making the same noise the other one did; kind of a squeaking/sticking noise. I checked with a straight edge and the spindle pulley looks about 1/16" higher than the drive pulley. It is not 'feeding' onto the pullley straight and I am thinking it will probably fail after awhile again.

Looking at the exploded veiw, and some pics in other posts, it looks like the spindle pulley is held on with a key to a step, and am wondering how the height can be adjusted. I have not taken it apart yet as I don't have a spanner wrench for the lock nut, but soaked it in WD40 in anticipation.

Has anyone had this problem?

[nitewatchman]

Adjust the Drive Pulley, the spindle pulley is fixed and shouldered on the spindle.

[BarnBurner]

How do you adjust the drive pulley? There is a bolt behind the motor that I don't see how I can get to without taking the cover off; and the oiler is attached to it.

[bjones]

so take the oiler and cover off, not rocket surgery.

[BarnBurner]

That's not the point. In the exploded view there is part #15, 31534, Adjustment washer - below the pulley.

There is also #96, 31595,Spindle Shaft adjustment washer. I can't find any info on how either of these 'Adjust'. It is easier to pull the pulley than take the cover and oiler off. And even if you take the cover off, the Allen head bolt is partially covered by the fins of the motor.

Have you taken it off bjones?

[tmarks11]

> the spindle pulley looks about 1/16" higher than the drive pulley

Let me be sure I understand your terminology:
-when you say spindle pulley, you are talking about PN65, the "shaft pulley)
-when you say drive pulley, you are talking about PN66, the "motor pulley)

I suspect that the "adjustment washers" acts as simple spacers. No adjustments possible, it is added to position the pulley at the right spot. You want a different spacing, you chose a different thickness "adjustment" washer.

It is possible that the M5 bolt (PN 103) holding the "motor pulley" (PN66) onto the motor shaft is loose, and the pulley has slipped down slightly. While you can look in underneath the motor in-situ, I am not convinced that what you see would tell you whether or not movement has happened. The motor mount plate (PN36) comes off pretty easy (since it is mounted in place with the two bolts).

Other thing to make sure is that the pivot bolt (PN102) that the spindle plate pivots on is tightened down.

The other option would be that the "shaft pulley" (PN65) attached to the spindle is loose and has popped up. It is held in place by a locknut (PN70), which is split with a screw (PN71) to lock it in place. It seems less likely that this would slip.

FWIW, the 1100 setup is identical to your drawing, so what I can see on my 1100 should apply to your 770.

I am assuming that this is a new problem, not that the mill was delivered from the factory with this misalignment and you finally noticed it (ie, it needs to be repaired because something has malfunctioned, vs. a modification to the design needs to be performed, such as adding a spacer ring between the motor and the motor mount plate to shift the motor upward).

[BarnBurner]

> the spindle pulley looks about 1/16" higher than the drive pulley

Let me be sure I understand your terminology:
-when you say spindle pulley, you are talking about PN65, the "shaft pulley)
-when you say drive pulley, you are talking about PN66, the "motor pulley)

Yes, that is what I meant. I typed that before I found the .pdf.

>

I suspect that the "adjustment washers" acts as simple spacers. No adjustments possible, it is added to position the pulley at the right spot. You want a different spacing, you chose a different thickness "adjustment" washer.

My idea was to machine a new spacer, I have a lathe. I am guessing the spacer is hardened steel and Aluminum would not be a good replacement.

It is possible that the M5 bolt (PN 103) holding the "motor pulley" (PN66) onto the motor shaft is loose, and the pulley has slipped down slightly. While you can look in underneath the motor in-situ, I am not convinced that what you see would tell you whether or not movement has happened. The motor mount plate (PN36) comes off pretty easy (since it is mounted in place with the two bolts).

Other thing to make sure is that the pivot bolt (PN102) that the spindle plate pivots on is tightened down.

The other option would be that the "shaft pulley" (PN65) attached to the spindle is loose and has popped up. It is held in place by a locknut (PN70), which is split with a screw (PN71) to lock it in place. It seems less likely that this would slip.

I can't get my hand in to check the PN103, or see underneath the pulley. I will see if I can scare up a dentist mirror or something similar. It doesn't feel loose.

The PN 102 (the back one) is abit loose, but maybe 1/64; not enough to account for the 1/16 difference. And it is tight once I snipe the other 102. I tried to get a Allen key in there, but there is no room. The only option I could see without taking off the Motor Cover PN52 would be to cut an Allen wrench and then use a socket on it. Also the cooling vanes on the motor are in the way to get to the Allen bolt (102).

At least I know the motor pulley is not pressed on, that makes it a good option to fix this. Thanks for the detailed reply, I appreciate the help.