Shopsmith Forums

algale wrote:I may well be wrong but let me re-phrase to make sure we both understand what I may be wrong about. The fact that you shimmed your main table wasn't the cause of the issue with the extension table (although perhaps that contributed a few thousandths of heeling). The issue was that with your extension table attached to the main table at the rear edge you were effectively creating a single surface with 3 pivot points (two trunnions under the main table plus the pivot point under the extension table). If the pivot point under the extension table was at a different height relative to the surface of the table than the other two pivot points, the combined surface would heel when tilted and the heeling would show up as a change of plane between the extension table and the main table.

I think I understand and agree to all of that with regard to the OFT. You are absolutely correct.

It took about one year of being frustrated by my OFT performance characteristics before I came to that realization. I have moved beyond that now. My OFT is still not dead on but I now know why and am no longer frustrated by that.

New Topic: The heeling of the table when moved from TS Mode to DP Mode is, in my mind, a different issue. Why? Because there is no third pivot point.

I have mocked this up in Sketchup and am playing with it now. My "starting opinion" is that we are dealing with either a less than perfectly flat main table or a pair of trunnions that are not perfectly related to one another.

It is also possible that my vision of "heeling" is inconsistent with what you are seeing.

As a test engineer, many of my most difficult tasks were compounded by a misunderstanding between myself and the design engineer. We often sat together to watch a test only to finish having seen two different results.

dusty wrote:I think I understand and agree to all of that with regard to the OFT. You are absolutely correct.

It took about one year of being frustrated by my OFT performance characteristics before I came to that realization. I have moved beyond that now. My OFT is still not dead on but I now know why and am no longer frustrated by that.

New Topic: The heeling of the table when moved from TS Mode to DP Mode is, in my mind, a different issue. Why? Because there is no third pivot point.

I have mocked this up in Sketchup and am playing with it now. My "starting opinion" is that we are dealing with either a less than perfectly flat main table or a pair of trunnions that are not perfectly related to one another.

It is also possible that my vision of "heeling" is inconsistent with what you are seeing.

As a test engineer, many of my most difficult tasks were compounded by a misunderstanding between myself and the design engineer. We often sat together to watch a test only to finish having seen two different results.

The heeling I was observing was not switching between table saw and DP mode but in table saw mode when tilting the table from flat to 45 degrees (to make a bevel cut).

I believe it was caused by my previously shimming the table to attempt to level it (front to back) to the quill in DP mode (I emphasize attempt because I did not take into account lack of table flatness when making measurements to level table to quill). By removing the shims, the heeling is gone in table saw mode. Whether I have lost level of the table to quill in DP mode remains to be determined as I have not had a chance to test it and I am not sure how to test given lack of table flatness.

algale wrote:The heeling I was observing was not switching between table saw and DP mode but in table saw mode when tilting the table from flat to 45 degrees (to make a bevel cut).

I believe it was caused by my previously shimming the table to attempt to level it (front to back) to the quill in DP mode (I emphasize attempt because I did not take into account lack of table flatness when making measurements to level table to quill). By removing the shims, the heeling is gone in table saw mode. Whether I have lost level of the table to quill in DP mode remains to be determined as I have not had a chance to test it and I am not sure how to test given lack of table flatness.

I have opened a new thread in Maintenance and Repair to carry on what I feel is a different discussion - Table Flatness.

A couple of thoughts about things that may contribute to the table not being level to the chuck in drill press mode that aren't related to either the trunnions themselves or table flatness.

When I tighten the headstock lock, my headstock moves slightly; by recollection it moves toward the back but I also would not rule out that it moves slightly up or down, suggesting the motion is slightly rotational. If it moves the same amount each time, you could get consistent alignment in table saw mode yet when the table is moved to drill press position, you might have a table not true to the quill.

I also want to check the carriage lock mechanism. If the carriage were to rack even slightly upon tightening, this, when the table is put in drill press mode would definitely put one end of the table higher or lower.

[quote="algale"]A couple of thoughts about things that may contribute to the table not being level to the chuck in drill press mode that aren't related to either the trunnions themselves or table flatness.

When I tighten the headstock lock, my headstock moves slightly]

It is highly probable that things will move (measurements will change) when you tighten the locks (each and every one of them).

This is why it is so important that all of the locks are secured before proceeding with alignments.

It has been my experience that the movement which occurs as you secure the locks will tend to be a movement back to the position of proper alignment.

Why Dusty's oft problem is the same as the dp/saw mode heeling.
Both are causes by 'stuff' moving differently due to a difference in 'pivot arm' length.

In Dusty's case, the oft had a different pivot arm length than the table trunions. Adding to the confusion in figgerin it out was the location of the oft pivot was not initially in line with the trunion pivots.

The unequal pivot arm length was created by Algale's shimming the table it dp position. When pivoted in saw mode the unequal pivot arm length revealed itself by the back moving to the right further than the front (heeling) when tilted for bevel cuts.

If one had checked for 'levelness' in both modes, the higher rear of the table might have been exposed then.

As I said earlier, quill, headstock, carriage, trunion posts, trunions, table . . . All could contribute to saw mode/drill press mode 'incompatibilities' due to the 90 degree rotation of the table.

I do not know what Dusty is saying in his new flatness thread, but a good straight edge is all that is needed(and a good eye and back light source).

Understand: flat and level are not the same thing. Flat means all points share a common plane. Level means that plane is also perpendicular to a line passing through the earth's center of gravity.

I wonder if that securing the locks do return to the headstock and carriage in the same position when it is done in tablesaw mode and Dp mode.

In TS mode both the headstock and carriage are pressing down on the way tubes and I would expect no movement other than side or side. Since any other movement would require lifting the headstock or carriage.

However in DP mode the headstock and carriage are not resting on anything until the lock is engaged. Here I could see movement in most any direction except upward. And I think that may even be effected depending on where I'm supporting the Headstock or carriage weight as I tighten the locks.

Also I think how you tighten the locks could effect the alignment. Using the right hand versus the left, pushing against the table or headstock versus not touchong either.

I don't know but I'm guessing there could be a ton of variables brought into play here.

The wedges will force the headstock/carriage away from the way tube upward when horizontal and towards the quill(same direction) in drill press mode. Whether gravity alters that I do not know, but tend to doubt it.

Gravity definitely will pull the outer table edge downward(post slop) in drill press mode.

With all of this discussion, there was never a declaration of the actual distance that must be considered when doing an out feed table like the one I produced.

Unfortunately, I lost all of my drawings and photos of the out feed tables that have I built.

I guess I'll have to recreate these and make some new measurements. A couple of you have had questions about how I did what I did. Please be patient and I'll try to put it all back together (the documentation that is).

PS: On my Mark V, the pivot point is located 1.299" (1 5/16") below the horizontal plane of the Main Table.

dusty wrote:With all of this discussion, there was never a declaration of the actual distance that must be considered when doing an out feed table like the one I produced.

Unfortunately, I lost all of my drawings and photos of the out feed tables that have I built.

I guess I'll have to recreate these and make some new measurements. A couple of you have had questions about how I did what I did. Please be patient and I'll try to put it all back together (the documentation that is).

PS: On my Mark V, the pivot point is located 1.299" (1 5/16") below the horizontal plane of the Main Table.

1 19/64 ?:D How many shims?;)