table alignment

[JPG]

I am not going to take my table apart for an investigation but I think that I would prefer that the pivot hole to be tight and the others loose. I don't see a reason for the whole table to float all over the place when trying to do an adjustment. If alignment can not be achieved without opening the pivot hole then manufacturing tolerances and assembly procedures need to be checked.
Bill V

A sleeve over the bolt(pivot) will do that!

[wa2crk]

JPG
Exactly!!
Bill

[JPG]

JPG
Exactly!!
Bill

A removable sleeve with all 4 holes 'big' will allow you to 'pick' the pivot point. It does not have to be one of the two 'accessible' ones. A loose screw will keep the sleeve captive and provide the pivot.

P.S. I did not mind 'taking apart' the 510 trunion, since I have not yet aligned it myself(WIP on back burner as noted below!).

[dusty]

I am not going to take my table apart for an investigation but I think that I would prefer that the pivot hole to be tight and the others loose. I don't see a reason for the whole table to float all over the place when trying to do an adjustment. If alignment can not be achieved without opening the pivot hole then manufacturing tolerances and assembly procedures need to be checked.
Bill V

I have drilled out three rear trunnions now and performing table alignment on these three tables is now a very simple task. Before doing that the alignments were something of a chore.

However, I would recommend doing this only to a table that is declared difficult to align. In other words, if it ain't broke - don't fix it (but please don't complain about the procedure being difficult).

Bill V: I know that you did not complain.

[algale]

I am not going to take my table apart for an investigation but I think that I would prefer that the pivot hole to be tight and the others loose. I don't see a reason for the whole table to float all over the place when trying to do an adjustment. If alignment can not be achieved without opening the pivot hole then manufacturing tolerances and assembly procedures need to be checked.
Bill V

That's what I thought. So I initially left the pivot point (right rear) at 3/8 and remounted the trunnoin. With the table upside down I tried to pivot things. It was better than before with just the one hole drilled out to 1/2 but I was leary of another 4 hour alignment party! So, I took the trunnion off again and redrilled that last hole to 1/2 just to be sure. Remounted the trunnion and alignment was a breeze, relatively speaking.

Now I'm not an expert on manufacturing so I can't comment on whether the tolerances and procedures need to be checked. But I can say that table does not "float all over the place" even with all 4 holes at 1/2 inch. The procedure Nick recommends in the first Sawdust session works well. Loosen both front trunnion bolts and the left rear trunnion bolt and snug them back up. As for the rear right trunnion bolt, make that one a bit tighter than snug and it works like a pivot point. In this configuration the table can be moved for alignment but it doesn't slide around all sloppy.

Your mileage may vary.

Alan

[robinson46176]

Tossing this out for thought. What if you mount an extension table on the right end at the same height as the main table, then loosen the trunnion bolts and slid the main table over close to the extension table and lock the carriage. Align the main table 90° to the quill then slip in wedges or shims between the main and the extension and clamp them together to hold the main in place and re-tighten the bolts.

????


.

[dusty]

Well, I've fixed that little problem (at least for now).

I now have a Shopsmith that is equipped with two trunnions that are both drilled with the larger size trunnion mounting bolt holes. I also now have two rear trunnions with the smaller holes. I removed one rear trunnion and replaced it with the front trunnion from the other table assembly.

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Now that I have done it, I'm not sure it was worth the effort. The movement of the trunnion is restricted by a nut on the center bolt that holds the rear rail on the main table.

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I also discovered that someone else (Shopsmith) has had this same problem. Looking at the photo of the the two trunnions, you can see that one of them has had some millwork done right where the mounting nut would touch the trunnion. [Left side/Top Trunnion/First Photo]

The potential interference between the rear/center rail bolt and the corner of the rear trunnion has been eliminated. Recent versions of the rear trunnion have been milled so as to eliminate interference.:):)

[DLB]

I know this is an old thread and an old subject to many here, but is it the consensus that a rear trunnion should have two 1/2" mounting holes like the front? I took one apart recently to look into tilt lock issues, and found that it is the version with two 3/8" holes. I know I don't want to stay with two 3/8" holes, but I'm wondering about leaving one as a pivot point.

- David

[dusty]

I know this is an old thread and an old subject to many here, but is it the consensus that a rear trunnion should have two 1/2" mounting holes like the front? I took one apart recently to look into tilt lock issues, and found that it is the version with two 3/8" holes. I know I don't want to stay with two 3/8" holes, but I'm wondering about leaving one as a pivot point.

- David

Here we go again. In the beginning, my rear trunnion had 3/8" bolt holes and the front trunnion has 1/2" holes. I got caught up in a movement to redrill the rear trunnions to 1/2" . I was/am able to align the table with the redrilled trunnions but I do not believe it is any easier. In fact, I regret drilling mine.

To align my table I loosen all four bolts so that the table moves freely in all directions. I then finger tighten all four bolts leaving just enough slack to allow table movement. I then push the table hard to the rear (outfeed) and hard to the right. Holding the table in this position, I firm up the two bolts that can be accessed with the table horizontal.

Doing it this way, I find the miter slots parallel to the blade to a level of precision that is adequate for safe and accurate cutting. If you meassure from the face of the blade to the near side of the miter slot to be 3 1/2" +-. I check that at the rear side of the table and the front for equality. If the measurements are equal and nearly equal to 3 1/2" I consider the table aligned.

This is a great departure from how I used to do this. Striving for accuracy to within a couple thousands is IMO not needed.

In fact, if you rip a piece of stable stock to 3 1/2" and use that as a spacer between the blade and the rip fence you should find the rip fence right along the edge of the miter track.

Bottom line - I recommend against drilling out the trunnion holes.

[reible]

Yea this is a mater of personal preference as much as anything. I had two identical models of hardware or so I thought. One was fast and easy to adjust and the other not so much. When Nick mentioned that some parts had gotten out with the wrong size holes I wondered if that might be my issue. Sure enough. I drilled mine out rather then have shopsmith replace them but you do need to take care when doing so as at least one member sustained an injury while doing so.

As you might guess I advocate the larger holes and have since the moment I made the change. Your mileage may vary. As mentioned above you can always add a bushing to one of the holes and see which seems easier to you.

Ed