Trouble with Trunnions

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DLB
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Re: Trouble with Trunnions

Post by DLB »

dusty wrote: Mon Nov 22, 2021 6:52 pm My apologies to SASman. I certainly pulled this thread off topic.
I don't think we have strayed far on this one. In fact I wanted to ask why you liked right front for a pivot as opposed to right rear. When I mentioned the SS video, it was the right rear that Nick suggested using as a pivot. Either right one works for me right now, but it changes which hole is actually drilled larger on the trunnion. Right front because it is closer to the center of the table, or some other reason?

I think we are on topic, there is a fair chance that SASman will enlarge either one or both holes, I expect.

- David
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dusty
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Re: Trouble with Trunnions

Post by dusty »

DLB wrote: Mon Nov 22, 2021 7:34 pm
dusty wrote: Mon Nov 22, 2021 6:52 pm My apologies to SASman. I certainly pulled this thread off topic.
I don't think we have strayed far on this one. In fact I wanted to ask why you liked right front for a pivot as opposed to right rear. When I mentioned the SS video, it was the right rear that Nick suggested using as a pivot. Either right one works for me right now, but it changes which hole is actually drilled larger on the trunnion. Right front because it is closer to the center of the table, or some other reason?

I think we are on topic, there is a fair chance that SASman will enlarge either one or both holes, I expect.

- David
I'm sorry! I did not intend to suggest that the small hole need be at any "specific trunnion bolt location. The mechanics works out the same which ever one is used.

When I align my tables the way that I have now adopted (since I regretfully drilled out all of my trunion holes) it doesn't depend on which one is the pivot point.
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SASman
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Re: Trouble with Trunnions

Post by SASman »

Okay,
Well the problem is apparently solved, at least for now. Switching the trunnions front to back worked. I hadn’t seen Dusty's first(?) post about it when I went out, picked up the framework minus the table, and one trunnion swiveled around and just about fell off in my hand. Quite a nice surprise.

Now the tabletop moves through the entire swing. I haven’t gotten to the point of drilling the hole(s) yet. I haven’t finished aligning it, and if it aligns correctly I shouldn’t need to.

I’m almost done, I hope. Last thing I can see needs doing is to replace the base mount and am waiting for the replacement which should arrive end of this week. The prior owner cracked the base arm somehow. Probably by having something between it and the base while the unit was raised to vertical and then forgot it and tried to lower the it. They are only small cracks and The SS can still be raised and lowered but I’d rather be cautious.
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dusty
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Re: Trouble with Trunnions

Post by dusty »

SASman wrote: Tue Nov 23, 2021 8:40 am Okay,
Well the problem is apparently solved, at least for now. Switching the trunnions front to back worked. I hadn’t seen Dusty's first(?) post about it when I went out, picked up the framework minus the table, and one trunnion swiveled around and just about fell off in my hand. Quite a nice surprise.

Now the tabletop moves through the entire swing. I haven’t gotten to the point of drilling the hole(s) yet. I haven’t finished aligning it, and if it aligns correctly I shouldn’t need to.

I’m almost done, I hope. Last thing I can see needs doing is to replace the base mount and am waiting for the replacement which should arrive end of this week. The prior owner cracked the base arm somehow. Probably by having something between it and the base while the unit was raised to vertical and then forgot it and tried to lower the it. They are only small cracks and The SS can still be raised and lowered but I’d rather be cautious.
To provide an understanding of what you are about to encounter, loosen all four trunnion bolts and then finger tighten them, Then push the table hard right or hard left against the trunnion bolts. Slide the headstock against the bumper and carefully measure the distance from the blade to either of the miter slots. Take this measurement at both the infeed side and outfeed side of the blade.

The difference in the two measurements tells you just how far out of alignment your table is.
"Making Sawdust Safely"
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DLB
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Re: Trouble with Trunnions

Post by DLB »

SASman wrote: Tue Nov 23, 2021 8:40 am Okay,
Well the problem is apparently solved, at least for now. Switching the trunnions front to back worked. I hadn’t seen Dusty's first(?) post about it when I went out, picked up the framework minus the table, and one trunnion swiveled around and just about fell off in my hand. Quite a nice surprise.

Now the tabletop moves through the entire swing. I haven’t gotten to the point of drilling the hole(s) yet. I haven’t finished aligning it, and if it aligns correctly I shouldn’t need to.

I’m almost done, I hope. Last thing I can see needs doing is to replace the base mount and am waiting for the replacement which should arrive end of this week. The prior owner cracked the base arm somehow. Probably by having something between it and the base while the unit was raised to vertical and then forgot it and tried to lower the it. They are only small cracks and The SS can still be raised and lowered but I’d rather be cautious.
Are you getting a complete base or just a new base arm? Reason I ask, not all base arms are created equally. There are at least two versions, three if you count double tilt. Differences, off hand, are hinge pin diameter and location of the set-screws for the way tubes.

- David
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Re: Trouble with Trunnions

Post by SASman »

I’m getting both parts of the base, the bottom, and the base arm. I thought about looking for just the arm section. Glad I didn’t. Looks like it should be here tomorrow or Friday.
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dusty
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Re: Trouble with Trunnions

Post by dusty »

What really effects Main Table Alignment to the Blade:
Shopsmith Main Table (Bottom View)<br />What effects Alignment to Blade?
Shopsmith Main Table (Bottom View)
What effects Alignment to Blade?
Main Tab;le Bottom Vierw.jpg (137.39 KiB) Viewed 934 times
Loosen the four trunnion bolts, push the trunnions hard against the bolts ( in any direction ), secure the bolts, and check alignments.
"Making Sawdust Safely"
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DLB
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Re: Trouble with Trunnions

Post by DLB »

dusty wrote: Thu Nov 25, 2021 6:37 am ...
Loosen the four trunnion bolts, push the trunnions hard against the bolts ( in any direction ), secure the bolts, and check alignments.
This will produce significantly different results on 510 and on tables with the 'old-style' trunnions compared to those with four trunnion holes the same size! With four 1/2" holes this gives you a good close starting point, but with two 3/8" holes and two 1/2" holes (like the OP has) it won't. If you have even one 3/8" hole, isn't the end result of alignment going to be all four bolts essentially centered (within a few thou) in their holes?

- David
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dusty
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Re: Trouble with Trunnions

Post by dusty »

DLB wrote: Thu Nov 25, 2021 8:29 am
dusty wrote: Thu Nov 25, 2021 6:37 am ...
Loosen the four trunnion bolts, push the trunnions hard against the bolts ( in any direction ), secure the bolts, and check alignments.
This will produce significantly different results on 510 and on tables with the 'old-style' trunnions compared to those with four trunnion holes the same size! With four 1/2" holes this gives you a good close starting point, but with two 3/8" holes and two 1/2" holes (like the OP has) it won't. If you have even one 3/8" hole, isn't the end result of alignment going to be all four bolts essentially centered (within a few thou) in their holes?

- David
I am seeking a trunnion that has not been drilled to 1/2" so that I can assemble and test this scenario but I don't expect a lot of change.

If only one trunnion bolt is 3/8", yes, That trunnion bolt becomes a pivot point and everything rotates around ot but the rotation is still limited to about .2 degree.

If either trunnion has two 3/8" holes, the amount of rotation is significantly limited. This was the contention when the recommendation to drill the trunnions first arose.

This sketch, however, was prepared by measuring each of the items in the assembly and transferring those measurements to the drawing. I did each part independently and then assembled the final drawing one piece at a time. The final is a collection of five different drawing superimposed and positioned according to my measurements. My model was my 520 fully assembled and critically aligned.

I believe that a 510/520 full table assembly could be aligned and mounted with no need for further tweaking. The Shopsmith is an assembled of well designed individual parts that when assembled properly produces a fine home multi-function tool.

I left dimensions off of this sketch on purpose. The intention is to highlight the fact that all of the parts that contribute to alignment are assembled either parallel to or perpendicular to other parts. If you would measure everything in the sketch, you would find that 1/16" increments prevail throughout. There are no extreme precision items involved.
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Re: Trouble with Trunnions

Post by JPG »

Regarding regretting drilling the 3/8" hole to 1/2"; get a 3/8 x 1/2 x ? bushing/sleeve/spacer and insert it into the hole needing reduction.
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