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Misaligned Drive Shaft?
Posted: Fri Aug 17, 2012 11:14 am
by mountain4don
I have a grey Shopsmith Model 505642 belt sander that has the M cast in the side of it probably left over from the "Magna" days. The problem I am having with it is I can't seem to align the driveshaft coupling very well horizontally. Vertically I adjusted it by loosening the set screws on the straight mounting shafts, but it still is maybe 1/4" or 3/8" inch horizontally back from the drive hub on the headstock. And I don't see a way to adjust it that way? In the instuction manual for setup it says that I can "rock" it back on the mounting tubes before tighening the set screws to align it. But that doesn't get me very far. And I am afraid the rubber drive coupling is going to break flexing like that. I can't even get one of the plastic drive couplings between the headstock and belt sander drive. Whats the solution for this before I break my drive coupling? Or are the rubber drive couplings (I haven't seen any of these for sale for a long time) ok with this?

Posted: Fri Aug 17, 2012 12:01 pm
by dusty
mountain4don wrote:I have a grey Shopsmith Model 505642 belt sander that has the M cast in the side of it probably left over from the "Magna" days. The problem I am having with it is I can't seem to align the driveshaft coupling very well horizontally. Vertically I adjusted it by loosening the set screws on the straight mounting shafts, but it still is maybe 1/4" or 3/8" inch horizontally back from the drive hub on the headstock. And I don't see a way to adjust it that way? In the instuction manual for setup it says that I can "rock" it back on the mounting tubes before tighening the set screws to align it. But that doesn't get me very far. And I am afraid the rubber drive coupling is going to break flexing like that. I can't even get one of the plastic drive couplings between the headstock and belt sander drive. Whats the solution for this before I break my drive coupling? Or are the rubber drive couplings (I haven't seen any of these for sale for a long time) ok with this?

It sounds to me as though you are trying to achieve horizontal alignment without having benefit of the
eccentric tubes.
Are the bandsaw mounting tubes straight or do they have an offset?
Posted: Fri Aug 17, 2012 12:38 pm
by SDSSmith
mountain4don wrote:I have a grey Shopsmith Model 505642 belt sander that has the M cast in the side of it probably left over from the "Magna" days. The problem I am having with it is I can't seem to align the driveshaft coupling very well horizontally. Vertically I adjusted it by loosening the set screws on the straight mounting shafts, but it still is maybe 1/4" or 3/8" inch horizontally back from the drive hub on the headstock. And I don't see a way to adjust it that way? In the instuction manual for setup it says that I can "rock" it back on the mounting tubes before tighening the set screws to align it. But that doesn't get me very far. And I am afraid the rubber drive coupling is going to break flexing like that. I can't even get one of the plastic drive couplings between the headstock and belt sander drive. Whats the solution for this before I break my drive coupling? Or are the rubber drive couplings (I haven't seen any of these for sale for a long time) ok with this?

As Dusty noted, alignment front to rear (horizontal) is more difficult without eccentric tubes. However, you might find that the belt sander aligns up better on the quill end of the machine. You might move the drive hub on the belt sander over to the other side and mount the sander in the right power mount. Move the drive hub from the upper auxiliary shaft to the quill. See if the alignment is any better. As far as 'rocking' the unit, I would rock it before tightening the power mount handle. If you end up high or low but with better horizontal alignment, you can always adjust the stop collars (hopefully, you do have stop collars). Lastly, if none of these work, you can always mess with the adjustment set screw in the headrest casting. But this will affect other alignments.
Posted: Fri Aug 17, 2012 12:44 pm
by mountain4don
dusty wrote:It sounds to me as though you are trying to achieve horizontal alignment without having benefit of the
eccentric tubes.
Are the bandsaw mounting tubes straight or do they have an offset?
Both of them have offset mounting tubes on them. Did the older green Shopsmiths from Magma line up better than the new grey ones? How did they align them in the "old" days?

Posted: Fri Aug 17, 2012 1:26 pm
by SDSSmith
mountain4don wrote:Both of them have offset mounting tubes on them. Did the older green Shopsmiths from Magma line up better than the new grey ones? How did they align them in the "old" days?

If you have the offset tubes, then you should be able to rotate them to get the proper horizontal (front to rear) alignment.
Posted: Fri Aug 17, 2012 1:53 pm
by algale
mountain4don wrote:Both of them have offset mounting tubes on them. Did the older green Shopsmiths from Magma line up better than the new grey ones? How did they align them in the "old" days?

Loosen the bolts under the headreast that secure the bench tubes and twist/rotate/skew one end of the headrest on the bench tubes toward or away from the base arm until the shaft of the SPT aligns horizontally with the aux spindle, then retighten. I think Bill Mayo and JPG are the ones that first suggested this. I haven't yet tried this myself but I think the idea has merit and plan to experiment with this over the weekend.
While using the leveling screw under the tie bar may also give you horizontal alignment, it will be at the expense of losing level between the way tubes and between the way tubes and bench tubes (assuming they already are level; if they aren't level you should make this adjustment).
As others have noted, you can also use the offset SPT mounting tubes to achieve alignment. An advantage of the Mayo/JPG method, theoretically, anyhow, over using the offset SPT tubes to achieve alignment is that the JPG/Mayo method may help keep alignment on an extension table moved from right to left or left to right.
Al