Main Table Stability....in Saw Table and Drill Press Modes

[algale]

My 520, bought used, had a table alignment issue. Short version is that the bosses that the fence attached to were not ground to tolerance. The result was that the fence went out of alignment when sliding between the main table and the extension or floating tables. I shipped the whole lot of table back to Shopsmith where Jim McCann nearly drove himself nuts putting shims on the bosses so all the tables play nicely together now.

[RFGuy]

My 520, bought used, had a table alignment issue. Short version is that the bosses that the fence attached to were not ground to tolerance. The result was that the fence went out of alignment when sliding between the main table and the extension or floating tables. I shipped the whole lot of table back to Shopsmith where Jim McCann nearly drove himself nuts putting shims on the bosses so all the tables play nicely together now.

Alan,

Thanks. Good to know. Yeah, that is exactly a system issue which is not easy for an owner to diagnose and can be problematic for a Shopsmith engineer to troubleshoot. To my knowledge, Jim is the only engineer they have at the moment and from Scott's last video he indicated that he is part time now presumably ramping to retirement. No product is perfect that ships from the factory and hopefully it is designed so that when everything is within manufacturing variance all is good. When it isn't frustration ensues...

[DLB]

But the proof is all over this forum that the Shopsmith is a fine woodworking tool. And I mean that in both senses. It's both a fine tool and it's a tool for fine woodworking.

This stability/instability dialog started in another thread, and we have kind of lost that context. Main table instability is a greater complaint to me personally than table tilt Vs. arbor tilt. The reason it annoys me is more about the additional setup time to stabilize the table via connector tubes etc. than about inaccuracy due to instability. I'm pretty happy with the stability when it is maximized by tying the main table to the extension via connector tubes. Also I'm pretty much okay with tilting the table for a cut, but I recognize that others don't like it.

- David

[BigSky]

I
Guess I do not understand stable
Is something moving that should not. If so, what.

[CreekWood]

I haven't owned a ShopSmith very long--in fact, I'm slowly getting around to cleaning up the SPTs that came with it. Honestly, the primary thing I've used it for so far is as an out feed for my existing table saw (which I'd consider replacing). But in my short experience, I have noticed table flex, even with the 520 tubes and the extension table. I first spotted this while attempting dowel joinery in the horizontal drilling mode. As I pushed down on the workpiece, I realized that was throwing off the hole placement.

Also, maybe I lack the squeeze to put the hurt on with my miter gauge, but the hold down simply can't keep the workpiece from being pushed by the advancing quill. The 520 fence, however, has way less slip than the one on my table saw.

[JPG]

The miter gauge HOLD DOWN is aptly named.

It is NOT intended to resist sideways forces.

[dusty]

The miter gauge HOLD DOWN is aptly named.

It is NOT intended to resist sideways forces.

For this discussion, I see the miter gauge (with its miter bar) and integral part of the table. There is some lateral movement of the miter bar in the miter track if not dealt with first.

A minor complaint of mine about the miter bar and/or miter track.

[dusty]

Unwanted movement could be introduced by:

The carriage lock not properly adjusted.

The Table Legs being loose in their carriage bores.

The Table not being securely attached to the Table Bar and Tube Assy

[dusty]

I
Guess I do not understand stable
Is something moving that should not. If so, what.

Whatever the source, there's a bit of of flex built into the various components and people refer to this as table stability.

The first type of table instability is related to table rotation or twist (not to be confused with the tilting table pivoting on the trunnions). Set your table flat like you were going to make a cut with the table saw and lock everything. Now grab your table at opposing corners and try to rotate/twist the table in the horizontal plane, i.e. turn it clockwise or counterclockwise. It will rotate/twist a little even if every table lock (table trunnion, table height, and carriage) is functioning properly. Personally, I don't find table rotation/twist to be much of an issue in real life operations because there aren't many or really any operations that apply a twisting force to the table. I suppose if you were ripping a long board and you had an assistant supporting the outfeed and the assistant levered the piece against the fence (or toward the blade), table rotation/twist it might be a problem. Fire that assistant and get a good roller outfeed support. In any event, idiot assistant or not, as long as your are not tilting the table for the operation you are performing and if you have the 510/520 table system, this rotational/twisting instability of the table can be virtually eliminated by connecting the main table to the extension table via the connector tubes.

The second type of table instability is what for lack of a better term I will described as "table assembly arc." Most commonly this is observed in horizontal boring mode when you apply a force with the quill to a work piece that is backed up by the fence. The entire table assembly can arc slightly to the operator's right when a force is applied from the left by extending the quill. Made worse by using dull drill bits and attempting to drill exceptionally hard woods into the end grain (whether "softwood" or "hardwood"). Drilling a pen blank would be real life example. Also an issue in drill press mode but not as easily observed. The arc is not huge but it is there and I suppose for certain absolutely critical fitments with tight tolerances it might cause problems. But, as with table rotation, "table assembly arc" can be largely eliminated on the 510/520 system in horizontal boring mode via the extension table/connector tubes as long as you aren't tilting the table. In drill press mode, using the tubes and support legs that come with the 510/520 will help eliminate table assembly arc.

In real life, table instability hasn't screwed up a project of mine.

This "first type" will happen if the Carriage Lock is not properly locked. The Carriage Lock Handle must be parallel to the floor when locked. It can feel locked (difficult to move) with the Lock Handle pointing up just a bit. Unlock and re-lock to correct this.

[JPG]

Dusty How about removing the non-bolded version.