Truing, As Best You Can, Shopsmith Table Tops

[dusty]

This thread is a direct result of still another closely related thread in " Maintenance and Repair ". That thread is entitled "What would cause this ". I contend that that question has many correct answers. Each and every one of them applicable to only a select group of Shopsmiths that all have the same physical characteristics.

To begin my contribution to this thread, I am going to declare that the very first thing one must do is verify the flatness of their own Main Table. I have four tables and not a single one of them is perfectly flat. I have the very best of the four mounted on my Shorty which is used predominately as a vertical drill press. The next best table (by my standards), is the one I have installed on the Mark V, Model 220. This machine is used predominantly as a power platform of the Table Saw and Jointer. I mention the Jointer only because it is there. The Tables have absolutely no impact on the Jointer.

The first thing that I do is verify that the Main Table, at ZERO TILT, is in fact positioned at 90° to the blade. I then remove the blade and the Blade Guard from the Headstock and set it aside.

Now you need a good straight edge. How straight depends upon how precise you want to be with your adjustments. Don't run out and buy a $50 Veritas unless you want to declare absolute precision; in which case you probably want to take a look at Starrett. I use a 48" level from a big box store somewhere. It has been around so long I don't remember where I got it.

Using your chosen straight edge, check all four edges and both diagonals of the Main Table for flatness. If all six measurements are exactly what you were hoping for, consider yourself very fortunate. None of mine are what I would like them to be. My Main Table has a high spot near the center of the table. It is not a major issue but the table is not flat and I am not certain that all four corners are in the same plane.

The next step will be to mount an Extension Table on the right end and to adjust it to match the Main Table.

[Ed in Tampa]

I wonder why Shopsmith tables aren't perfectly flat. They are obviously surfaced ground, I would think if you are going to bother grinding them you would make them flat.

[Ohgary]

I wonder why Shopsmith tables aren't perfectly flat. They are obviously surfaced ground, I would think if you are going to bother grinding them you would make them flat.

don't they mount with threaded fasteners from below? Differences in torque could distort the metal, couldn't they?

[dusty]

I wonder why Shopsmith tables aren't perfectly flat. They are obviously surfaced ground, I would think if you are going to bother grinding them you would make them flat.

don't they mount with threaded fasteners from below? Differences in torque could distort the metal, couldn't they?

Yes, they do mount that way and Yes, you can torque them into a twist. To avoid this, I tighten the bolts finger tight while I am making adjustments and then further tighten them by hand and then with a wrench. For the final step, I tighten each bolt just a little and then finally secure them in the same manner with a wrench.

BTW, Nick has gone on record as saying the tables can not be torqued into a twist. You can read that statement in the link I posted in this this thread. In this post he is talking about the Main Table and the trunnion bolts - not the extension tables.

[dusty]

I wonder why Shopsmith tables aren't perfectly flat. They are obviously surfaced ground, I would think if you are going to bother grinding them you would make them flat.

I believe we have been down that road before (maybe several times).

http://www.shopsmith.com/ss_forum/viewt ... tness#p729

[JPG]

The table is aluminum and is 'ductile'. That means it can move under stress. Whether it returns to original shape depends upon the stress. Securing with screws does not allow any 'returning' until the screws are removed. Proper shimming can minimize the distortion caused by the screws.

Ain't nothing perfectly flat anyway.

Cast iron or granite can get close, but they are too heavy for this application.

So accept it for what it is.

OK continue Dusty.

[dusty]

Mating the Right Extension Table to the Main Table

At this point I move the Carriage to the right until the right edge of the Main Table and the left edge of the Right Extension Table Align vertically. After adjusting the Extension Table so that its height approximates that of the Main Table, I loosen all of the nuts that secure the Extension Table. Then I insert a pair of tubes through the rails of the Extension Table and the Main Table and tighten the screws that secure the tables to the rails. Hopefully this creates a flat surface and an almost disappearing joint between the Main Table and the Extension Table. The Extension Table has just become a 7" extension of the main table.

It is at this point where I secure those bolts and nuts on the bottom of the Extension Table. Before doing that, move the support leg up under the Extension Table so that it just touches but does not move the table. After securing the Extension Table to the support legs, I remove the extension tubes from within the rails hoping that when I do so the tables remain in the same relative position. If they do not, something has been done incorrectly.

Checking this pair of tables from corner to corner diagonally will tell you whether or not you have been successful. Remember the results for when you did this with just the Main Table. Those results will have some bearing on what you experience here.

Again I say, perfection is NOT going to be achieved.

[dusty]

Now Move to the Other End and Do the Same Thing

Only difference being that you cannot get the tables as close together.

After achieving that relationship, center the Carriage between the Extension Tables and check diagonally from Extension Table to Extension Table.

If you have a Mark 7 you might want to swap Extension Tables end for end and do a complete recheck but if you don't have a Mark 7 I believe I already know the results. They will be miserably disappointing. But no problem. Put them back where they were first aligned, mark them left and right and always setup that way. Be prepared to tweak them now and then. This is the nature of the beast.

[JPG]

I do not think this is 'miserably disappointing'.

http://www.shopsmith.com/ss_forum/viewt ... 99#p193899

[dusty]

This is miserably disappointing. What you see here is the front rail missing the hole in the right rail after swapping previously aligned extension tables end for end.