Beltsander Alignment

[DLB]

It turns out that the stud being loose was more critical than I initially thought. The trunnion guide track was moving a bit on the base, and pressing that stud in with a C-clamp greatly reduced the movement. As far as I can tell with the sander disassembled it has greatly reduced but not eliminated the original problem.

The Sander Base Assembly is evidently only available as an assembly and includes the Sander support (base casting), Trunnion track, and two Drive studs. There seems to be some play in the holes for those studs in the trunnion track, or mine have elongated over time. Since it is only available as an assembly I am thinking that the guide track is aligned in production. It would follow that mine is not aligned.

-David

[reible]

I mounted my belt sander and played with the alignment and found that while it appears to move out of alignment when moving from vertical to horizontal or the other way around as soon as I tighten the lock it goes back into alignment. I did it several times and stopped at various places where it appeared to have gone out of alignment but as soon as things snug up it back to being right on.

Ed

[JPG]

Sorry for getting up on my cracker box, BUT:

That big set screw that adjusts the 'twist' of the way tubes should NOT be adjusted to achieve shaft alignment(in spite of recommendations by the mother ship crew to the contrary).

Horizontal(in/out) alignment of the shafts is achieved by rotation of the entire base casting(legs and all) and should also result in the SPT mount bores being perpendicular to the way tubes length. This is a accomplished by rotating the base casting about a vertical axis. Tilt of the aux table is done by adjusting the mount( shimminhg or use of studs/lock nuts).

IMO the SPT offset/eccentric mounting tubes allow for what should be minor variations between individual SPTs. For decades straight tubes worked and the coupler made up for those minor differences.

Getting down off the box.

Yes this is slightly off topic, but points out there is much that affects it.


P.S. I missed the post above re the trunion. IMO mystery solved.

[DLB]

JPG, I agree 100% with what you are saying, so I think we've miscommunicated or are doing so now. I should have said that my expectation of neutral H offset (or good H alignment using straight tubes) is based on it being a by-product of a well-aligned base, to include adjustment of the big set screw. I did not adjust the big set screw to achieve shaft alignment, I adjusted it according to a process you advocated in another thread using a marked extension table base as a transfer standard. Horizontal shaft alignment, IMO, is a by-product of that process assuming that the base is otherwise aligned, the SPT is sound, and SPT manufacturing variation is minimal.

I was mostly trying to communicate this because Dusty has mentioned in a couple of threads that his horizontal adjustment is never neutral. I'm confident that both of you know more about base alignment than I do. Explaining my expectation, restated above, is intended to improve understanding because I'm pretty sure that Dusty does not share that expectation.

-David

[dusty]

JPG, I agree 100% with what you are saying, so I think we've miscommunicated or are doing so now. I should have said that my expectation of neutral H offset (or good H alignment using straight tubes) is based on it being a by-product of a well-aligned base, to include adjustment of the big set screw. I did not adjust the big set screw to achieve shaft alignment, I adjusted it according to a process you advocated in another thread using a marked extension table base as a transfer standard. Horizontal shaft alignment, IMO, is a by-product of that process assuming that the base is otherwise aligned, the SPT is sound, and SPT manufacturing variation is minimal.

I was mostly trying to communicate this because Dusty has mentioned in a couple of threads that his horizontal adjustment is never neutral. I'm confident that both of you know more about base alignment than I do. Explaining my expectation, restated above, is intended to improve understanding because I'm pretty sure that Dusty does not share that expectation.

-David

Until I attempt the set up with straight tubes I will not know. I received the eccentrics that I have with the equipment when it was new and I have never set up with any thing else. I just know that I need the offset provided by the eccentric to get horizontal drive hub alignment.

If you remove a table from one of your extension tables and carefully mark the center of the support bracket on top and then install that into either the base or the headrest and push the headstock to one end or the other you will see evidence of your horizontal alignment - be it dead on or otherwise.

Another mysterious point - the large set screw has not been adjusted on any of my machines except to back if off so that it makes no contact with the casting. Adjusting it does nothing for me.

[JPG]

Yes the effect is quite subtle.

[JPG]

JPG, I agree 100% with what you are saying, so I think we've miscommunicated or are doing so now. I should have said that my expectation of neutral H offset (or good H alignment using straight tubes) is based on it being a by-product of a well-aligned base, to include adjustment of the big set screw. I did not adjust the big set screw to achieve shaft alignment, I adjusted it according to a process you advocated in another thread using a marked extension table base as a transfer standard. Horizontal shaft alignment, IMO, is a by-product of that process assuming that the base is otherwise aligned, the SPT is sound, and SPT manufacturing variation is minimal.

I was mostly trying to communicate this because Dusty has mentioned in a couple of threads that his horizontal adjustment is never neutral. I'm confident that both of you know more about base alignment than I do. Explaining my expectation, restated above, is intended to improve understanding because I'm pretty sure that Dusty does not share that expectation.

-David

Roger!