# Belt misalignment on Clausing 54XX



## AndySomogyi (May 25, 2020)

I recently rebuilt most of the head stock and install all new belts and bearings on a 5428, and having a weird issue where the front idler seems to drag the belts to the left.

without the idler, the belts are straight. I verified that the jack shaft here is parallel with the spindle and that the pulleys are lined up.

Got the belt tension a little lower than an automotive belt, more tension the more the belts get dragged to the left.

any ideas what could be going on here.

There isn’t much of an angle that you can cock the idler, but I’ve got it cocked as far as it will go to try to move the belts to the right. I really really really don’t want to pull the spindle out again


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## BGHansen (May 25, 2020)

Tough without seeing it live, but you understand what's going on which is 99% of the battle.  I would think your spindle is the "datum" axis, so by definition it is perfect and everything else should move relative to it.  Maybe put a couple of washers under one side of the blocks that mount the horizontal rods to the base and see if it gets better or worse?  If better, there's your fix. If worse, shim the other side.  

Or (same concept) loosen the lathe attachments to the base cabinet on the head stock end and rotate the base CW or CCW. Fire it up and see if it helps or hurts.

I have a Clausing 5418, will take a peek at mine and see how it runs. I might have the same condition and just haven't noticed it.

Bruce


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## AndySomogyi (May 25, 2020)

I checked the shaft parallelism of the spindle and jackshaft in both the Y-Z and X-Z planes, and it's really close, maybe at most a degree off. Made a video of the idler here.

I thought a bit about what you said about adding shims under it. You know, that might just work. So, if I added a shims under the outer side of that idler assembly, that will cock it down in the vertical direction, so the idler won't be exactly perpendicular to the belt. Because it's not perpendicular, this will result in a deflection force on the belt, that will force it towards the chuck side (where it needs to go). That just might work, I like it. Thanks man! I'll give it a shot.

Here's a video I made of it running:








BGHansen said:


> Tough without seeing it live, but you understand what's going on which is 99% of the battle.  I would think your spindle is the "datum" axis, so by definition it is perfect and everything else should move relative to it.  Maybe put a couple of washers under one side of the blocks that mount the horizontal rods to the base and see if it gets better or worse?  If better, there's your fix. If worse, shim the other side.
> 
> Or (same concept) loosen the lathe attachments to the base cabinet on the head stock end and rotate the base CW or CCW. Fire it up and see if it helps or hurts.
> 
> ...


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## AndySomogyi (May 25, 2020)

Has anyone seen this kind of issue before? 

I know my lathe was running for 50 some odd years before I got it, so it somehow must have worked OK like this. But it originally came with cloth covered belts, and I put solid rubber ones on it, I wonder it that's my problem.


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## AndySomogyi (May 30, 2020)

Tried shimming one side of the idler, and don’t help much. Think what’s going on is the belts all wonky in the pulley. When I first put them in, one belt tried to walk out, and wore the side, which made the problem worse.

So I’m making a new idler with guide grooves to help align the belts. I don’t know, you suppose 1/16 deep is enough?





BGHansen said:


> Tough without seeing it live, but you understand what's going on which is 99% of the battle.  I would think your spindle is the "datum" axis, so by definition it is perfect and everything else should move relative to it.  Maybe put a couple of washers under one side of the blocks that mount the horizontal rods to the base and see if it gets better or worse?  If better, there's your fix. If worse, shim the other side.
> 
> Or (same concept) loosen the lathe attachments to the base cabinet on the head stock end and rotate the base CW or CCW. Fire it up and see if it helps or hurts.
> 
> ...


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## AndySomogyi (May 31, 2020)

Tried shimming one side of the idler, and don’t help much. Think what’s going on is the belts all wonky in the pulley. When I first put them in, one belt tried to walk out, and wore the side, which made the problem worse.

So I’m making a new idler with guide grooves to help align the belts. I don’t know, you suppose 1/16 deep is enough?





BGHansen said:


> Tough without seeing it live, but you understand what's going on which is 99% of the battle.  I would think your spindle is the "datum" axis, so by definition it is perfect and everything else should move relative to it.  Maybe put a couple of washers under one side of the blocks that mount the horizontal rods to the base and see if it gets better or worse?  If better, there's your fix. If worse, shim the other side.
> 
> Or (same concept) loosen the lathe attachments to the base cabinet on the head stock end and rotate the base CW or CCW. Fire it up and see if it helps or hurts.
> 
> ...


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## AndySomogyi (May 31, 2020)

Decided to make the grooves 0.100 deep, and rounded corners. Hoping the rounded corners sort of round the belt and cause to to be more self tracking


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## BGHansen (May 31, 2020)

I looked under my 5418 and have the same thing. Much to my chagrin,  I've never aligned the 3-groove drive pulley in the base with the spindle shaft. I don't see any wear on the belts which have been running like that for 30 years. Still need to add it to my list of good intentions. 

Bruce


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## AndySomogyi (Jun 5, 2020)

Everything I tried with alignment failed, but I did end up re-engineering a part and fixed the belt issue.

Got longer post here on how I fixed the issue









						Clausing 5428 rebuild
					

Outstanding! I did not know about the bearing alignment. Thanks Robert  Thanks, I didn’t either until I read up on the intricacies of precision bearings a few weeks ago.




					www.hobby-machinist.com


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