Extension table alignment and rip fence

[keakap]

I think what I should do now is meticulously measure all 4 tables both with and without rail inclusion and post it here. I don't want to mislead.

When over the years I ran into misalignment problems I did the "well I know they're off, so what da hay" shrug and went on as best I could. Could be I'm overdue for an up close and personal review of the basics, and I've not done that completely with the replaced, square, flat, shiny Main table vs the rest.

I too am anxious to hear if Bruce found his answer.

Aloha, y'all. (from southern Hawaii)

[dusty]

I am relatively certain that all of my tables were manufactured by Shopsmith but they do not all look alike. That being the case, I decided that I better make some quick measurements.

The tables that I have all measure very, very close to 22" (maybe 21 31/32"). I don't have anything to mic something that large so my measurements were made with a long steel rule.

It is important to note that these measurements are all taken from the front boss to the rear boss. The edges of the actual table surfaces are not consistent but the bosses are.

With two tables on the front rail, side by side - the bosses line up exactly (both front and rear). The bosses, however, differ somewhat from table to table. I have one table whose bosses are considerably thicker than the others.

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[nuhobby]

Dusty, I see your feet are about 2 inches long. No matter -- do they match, I guess, is the critical point?

[a1gutterman]

Dusty, I see your feet are about 2 inches long. No matter -- do they match, I guess, is the critical point?

That is funny, Chris!!!

[keakap]

Good pics, Dusty!
Definitely worth all 3,000 words.

[dusty]

Good pics, Dusty!
Definitely worth all 3,000 words.

I just reread this thread and realize now that you do not have a 520. This is only significant because the installation/alignment procedures for the 505/510 specifically mention using shims to align the tubes. I suspect that 500 procedures are the same as 505/510.

If you have not installed shims to align the rails, I think you should try that as a first effort. Reference post #15 in the following thread for detailed contents of the help kit (515325). http://www.shopsmith.com/ownersite/itemfind.htm?item=515325&Submit=Find+Item The shims that I still have are .004". This tells me that Shopsmith did not expect too much deviation.

I do not believe that this should be a deterrence to your installing a 520 upgrade kit. If the same problem existed with a 520 rail, it could be resolved the same way (with shims).

You should also check your 4' tubes to make certain they are straight. A bent tube could cause symptoms very similar to what you describe. Just roll your tubes across a flat surface - if they are not straight, it will be obvious.

[dusty]

Thanks, guys. Ed, to answer your question, the problem was there before I realigned the extension table. I also noticed that at the time I installed the 520 upgrade, I shimmed the rear guide on the main table, probably to correct an alignment problem. Since then, I have discovered Nick's alignment method, so I think I will remove those shims and try the alignment again and see how the fence works then. Thanks again for your input.

Do you still have a problem, Bruce or have you resolved it by now? Just curious. This thread did start with your report.

[dusty]

I have just done what I probably should have done when I began commenting in this thread. I reread the procedures provided by Shopsmith (the manual). As is so often the case for me, my memory does not match reality.

The alignment procedures for the front and rear rails/tubes do not make use of shims. The shims are used only for aligning the main table and are installed on the trunnion mounting bolts as required. I realized this when I checked the shims for thickness and noticed how large the ID was on the holes in those shims.

This does not mean that you cannot resolve and alignment problem by using shims but the ones provided in the help kit won't do the trick.

[JPG]

I have just done what I probably should have done when I began commenting in this thread. I reread the procedures provided by Shopsmith (the manual). As is so often the case for me, my memory does not match reality.

The alignment procedures for the front and rear rails/tubes do not make use of shims. The shims are used only for aligning the main table and are installed on the trunnion mounting bolts as required. I realized this when I checked the shims for thickness and noticed how large the ID was on the holes in those shims.

This does not mean that you cannot resolve and alignment problem by using shims but the ones provided in the help kit won't do the trick.

I have learned(in my short term on the forum) to go to the hardware for a memory refresher B4 making a post. Many times I have prevented getting bird embryo on my face!:eek: Earlier I didn't!:o

We seem to share the memory affliction. Such is the price for 'Wisdom'!???:rolleyes:

[dusty]

As a result of this thread and my own inability to envision what the problem might be, I changed one of my main tables and a floating table back to a 510 configuration.

I then proceeded to do a complete table alignment. To make this an honest effort, I loosened all of the nuts that secure the rails to the two tables and started from scratch.

What did I learn (if anything):

1) The tubes that you use for this process must be straight. A bent tube can be detected by simply rolling it on a flat surface. I set aside one tube that I have been using regularly in my setups.

2) The alignment of a 510 table set is a bit more demanding than the same procedure for a 520.

3) The distance from the plane of the tables to the top of the rails (front and rear) is 3/8". I am going to make up a jig that can be used for this alignment. I believe it would make the procedure much less painful. The jig will serve the same purpose for the 510 as does the aluminum gauges that are recommended for use with the 520.

4) Once properly aligned, the 510 is every bit as accurate as the 520.

5) To complete the alignment, I ended up using a .043" shim on one end of the extension table. I sorted through a few flat washers to get the right one.

The jig that I am going to make will be something like this. Except that I left off a critical dimension. I will make it 26" long so that it will span both a main table and an extension/floating table.

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