Re: Disaster when changing the poly v belt

JPG · Post by **JPG** » Thu Mar 19, 2015 12:20 am

Resuming a thread started in the Beginning Woodworking forum.

Shredding 'sounds' like the poly-v belt is not aligned.

The belt should be 'centered' on the idler shaft pulley. That is, a belt rib in every pulley groove.

The poly-v belt should be in the 3rd or 4th groove from the quill end of the drive sleeve pulley. Opinions/instructions vary, but which ever one provides the better alignment should be used. That means 2 or 3 grooves visible on the quill side of the pulley.

When tensioning the poly-v belt, one must first make certain the belt ribs are firmly in the pulley grooves(A given rib ONLY in one pulley groove.

Verifying that alignment and tensioning can be done without the motor belt installed or the motor actually running.

The 'shredding' may have been caused by the poly-v belt 'jumping' across the pulley ribs.

rdewinter · Post by **rdewinter** » Thu Mar 19, 2015 11:09 am

Poly v belt replacement disaster. Here are some pics as to where I'm at.

: image.jpg (199.93 KiB) Viewed 3886 times

You can see the belt is starting to shread. I might be able to cut that one strand that has seperated off. I need more adjustment room to move the poly v belt but it won't move. I have removed hte drive belt. But the eccentric bearing seems to be stuck. I can turn the eccentric bearing a little bit but not enough to get it out or make adjustments.

Other pics of current status

: image.jpg (199.93 KiB) Viewed 3886 times

: image.jpg (154.04 KiB) Viewed 3886 times

I might need to have the headstock sent to a repair service to fix it correctly.
I'll post another thread to see if there is a West Coast repair service somewhere in Southern California that is reliable.

everettdavis · Post by **everettdavis** » Thu Mar 19, 2015 11:26 am

JPG is right. It should look more like this one that was posted by 'bobgroh' in post #39084

: Poly-V Headstock bobgroh 39084.jpg (5.77 KiB) Viewed 3879 times

Reference http://www.shopsmith.com/ss_forum/viewt ... elt#p39084

From the inspection port view, the Loop that is supposed to be over the clip and beyond the detent on the Quadrant, but it is between the Quadrant and the Idler Shaft. See attachment for where it should be.

: Quadrant Loop and Idler Bearing Button.jpg (21.3 KiB) Viewed 3858 times

The Quadrant or mounts in your photo appears to be bent just a bit as the Quadrant should line up dead center on the button attached to the bearing in the Idler Shaft that rubs on the face of the Quadrant.

That suggests that the speed dial may have been turned with machine off and without the belts and pulleys rotated, a practice known to cause that to bend.

It needs some maintenance for certain and does not need to be powered until those issues are remedied to prevent further problems.

Everett

wa2crk · Post by **wa2crk** » Thu Mar 19, 2015 11:40 am

The poly V belt is definitely mis-positioned. It should be in the second or third groove from the left edge of the pully. If it was positioned incorrectly when it was first installed it may have walked into position and as a result torn the ridges off the belt. It MAY be ok to use it in this condition if the rest of the V's have been torn also. My gut instinct would be to replace it.
The eccentric is obviously too far out of the headstock. When I install the eccentric I position the polyV belt on the pullies and insert the eccentric from the outside of the casting. Keep the eccentric's thinnest wall to the 12 o"clock position this keeps the idler shaft at its highest position and minimum tension on the belt.
Cleaning the components and the headstock bore and removing any burrs will also help assembly. A bit of light oil will help as well.
I also noticed that the clip on the end of the control sheave is off the pork chop spring. If this is as you found it then I would advise you to check the bearing in the end of the control sheave.
YOU CAN DO THIS. A repair service would cost a lot more than some extra parts. But the learning experience will be priceless.
Come back when you need more help.
Bill V

wa2crk · Post by **wa2crk** » Thu Mar 19, 2015 11:49 am

Re my previous post: 4th sentence should read "if the rest of the V's have NOT been torn also"

everettdavis · Post by **everettdavis** » Thu Mar 19, 2015 12:04 pm

There should be a washer and a screw in the hole at 1:00 in reference to the eccentric bushing that keeps the bearings in the eccentric bushing from walking out the bushing as it has in the picture.

Again, these are things you can fix and folks here are glad to help. We have all had to do a variety of things the first time ourselves, and together this family supports each other.

There are a series of documents that you will find on the sticky posts at the top of the maintenance thread that will really help frame how to do things efficiently.

Get a cup of coffee or a soft drink and start working through those and I think you will be able to remedy these things yourself fairly straightforwardly.

JPG · Post by **JPG** » Thu Mar 19, 2015 12:40 pm

I assume the eccentric/washer(s)/screws are out because you are trying to adjust the poly-v belt tension(make it loose).

I would first push the eccentric back in until it is flush with the casting.

Then rotate the eccentric until the wide slot is at 6 o'clock. That places the thin side at 12 o'clock as WA2crk mentioned.

Next I would remove(or at least make it completely slack) the motor belt so it is not tugging on the idler shaft.

Hopefully having done those two things, the eccentric will slip into the headstock.

We be assuming you have loosened the clamping screw that secures the eccentric.(do not over tighten that screw later!!!)

The poly-v belt will not 'slide' on the pulley. The belt must be slack enough to raise the ribs high enough to pass over the pulley ribs. Usually that must be done one rib at a time. Since the belt is 'centered' on the idler pulley hub, the pulley/idler shaft need to be free to slide with the bent being moved.

Now at the other end of the idler shaft is a more serious(maybe) problem.

Step one there is to remove the speed control. Knob setscrew and three screws. Make sure the teeny 'anti-rattle' spring nor the loop do not get 'lost'.

If lucky, the 'loop' will merely be 'loose' and not damaged. Ditto the control sheave button/bearing.

All this can be intimidating at first, but actually it is not difficult.

We can address the bent arm on the speed control later!

beeg · Post by **beeg** » Thu Mar 19, 2015 1:23 pm

wa2crk wrote:Re my previous post: 4th sentence should read "if the rest of the V's have NOT been torn also"

Do you know that you could have "edited" your previous post?

wa2crk · Post by **wa2crk** » Thu Mar 19, 2015 8:38 pm

Beeg
I do about the edit function but I posted as a "quick reply" and I could not find a edit function for the quick reply post.
Bill V

OK now I see it. Wasn't obvious before.

beeg · Post by **beeg** » Thu Mar 19, 2015 10:31 pm

It should be above the name of the thread.

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