Table Tilt Lock, Mark V Model 510/520

[dusty]

I agree with all that algale said. But I would add that I think it is possible, or at least plausible, to accidently induce a larger gap when following one of the 'standard' alignment procedures. I can feel on mine that if I use the tilt lock to pull the trunnions into proper position they have some tendency to bind on the 'axle.' If they bind during assembly, installation of the table is going to lock in that incorrect setup.

... On the bench (without a table attached) those gaps differ. Obvious I guess because with the table attached the trunnions are a fixed distance apart (14 13/16" by my measurement). On my setup in the shop the distance is 14 1/2" (with the table tilt lock applied)...

I don't understand this, especially the 14 13/16" part. I measured two, one on the bench without a table measured slightly under 14-1/2", ~14-15/32". The other, with a table, measured very slightly over 14-1/2". These are both with the tilt lock applied. IMO, the difference would have something to do with manufacturing variation and/or wear, not the presence or absence of a table. Please explain the 14-13/16" measurement, I think this could be the key.

- David

I didn't make myself clear. I imposed the separation between the trunnions with the piece of wood. This was intended to simulate the trunnions hard locked to the main table.With this restriction I can still lock the table tilt and there remains a small gap between the boss on the table bar and the trunnion. This leads me to believe that friction between the boss and the trunnion is NOT relied upon to provide lock.

If I remove that piece of wood and apply the tilt lock, the trunnions close to 14 13/16" and lock the trunnions. The 14 13/16" separation is created by the table bar in this case (without the wood and without a table.

Bolting on a table makes all of these measurements of function of the table during alignment.

The piece of yellow sticky can be pulled out without effecting locking action. (the dollar bill trick).

[algale]

I agree with almost everything you said. However, I do not buy into the theory that tilt lock is achieved by anything other than friction between the two aluminum blocks and the trunnions.

The dollar bill trick only ensures that there is some spave between those bosses and the trunnion.

To confirm: tilt the table to vertical, lock the tilt lock and attempt tp insert the dollar bill (or piece of paper) between the boss and the trunion (showing that locking action does not involve the bosses on either end of the table bar.

If I pull the 14.5" spacer out and tighten down on the tilt lock, the wedges are forces inward and capture the trunnion. Yes it is locked and the trunnions are in hard contact with the table bar but the trunnions are also not separated as they would be if bolted to the table.

I think that's an experiment that can only be performed on a mounted table.

I don't believe the table determines how far apart the trunnions are when an alignment is performed. That distance is controlled by the distance between the bosses on the opposite ends on the tie bar (plus the thickness of the dollar bill if you use one during alignment).

Since the trunnions are already locked in firm contact with the tie bar bosses (plus dollar bill is you use one) when the table is tightened down to the trunnions, the trunnions don't or shouldn't move. But if you used the dollar bill, I do believe when the lock is applied the trunnions will move and close the gap left behind when the dollar bill was removed (if you used one). I believe this will put the table top in a tiny amount of compression/tension.

By the way, I count a total of eight points of contact between the table and the trunnions. If for whatever reason any one of these surfaces is proud of or short of the others, I can envision the table being put in slight compression/tension or even slightly twisted when the table is firmly bolted down to the trunnions. When the table lock is released, I could see the table springing back to shape and the trunnions springing out slightly from where they were when the alignment was performed creating a gap (or a larger gap if the dollar was used).

I admit this is theoretical and I don't think I have the equipment to measure any of this.

[stew]

I had this problem for a long time and finally figured out that the specialty nut that the rod threads into had some of the threads beginning to strip. I ended up filling the threaded hole with that aluminum rod stuff that you can melt. I then drilled and tapped the hole again and it worked great. It was hard for me to determine it was those threads because the table would hold sometimes but progressively got worse. Good Luck.

[dusty]

I had this problem for a long time and finally figured out that the specialty nut that the rod threads into had some of the threads beginning to strip. I ended up filling the threaded hole with that aluminum rod stuff that you can melt. I then drilled and tapped the hole again and it worked great. It was hard for me to determine it was those threads because the table would hold sometimes but progressively got worse. Good Luck.

Interesting input. Thank you.

I'll just replace the lock handle mechanism with a not and secure it with a nut driver. This will allow me to pin point or eliminate the specialty nut as the culprit.

[DLB]

...The piece of yellow sticky can be pulled out without effecting locking action. (the dollar bill trick).

When I set mine up with a gap (dollar bill trick) that gap closes when I lock my table afterward. I confirmed visually with light behind it and using a thin (.002") feeler gauge. I'll try again later with a somewhat wider gap, two or three sheets of thick paper.

- David

[algale]

...The piece of yellow sticky can be pulled out without effecting locking action. (the dollar bill trick).

When I set mine up with a gap (dollar bill trick) that gap closes when I lock my table afterward. I confirmed visually with light behind it and using a thin (.002") feeler gauge. I'll try again later with a somewhat wider gap, two or three sheets of thick paper.

- David

Thanks, David. That's what I assumed happened. I don't use the dollar bill trick anymore and didn't want to do a whole new alignment just to prove what I believe has to happen.

[dusty]

It is a function of how far apart the trunnions are.

The dollar tricks only purpose is to eliminate drag when you change table tilt (table tilt unlocked). In other words, the trunnions are always further apart than the width of the table bar measured at the bosses.

[algale]

It is a function of how far apart the trunnions are.

The dollar tricks only purpose is to eliminate drag when you change table tilt (table tilt unlocked). In other words, the trunnions are always further apart than the width of the table bar measured at the bosses.

David just said that the dollar bill gap does close when he locks his table. I have no doubt that one could increase the gap too far for gap to be closed by the pressure exerted by the locks.

[dusty]

It is a function of how far apart the trunnions are.

The dollar tricks only purpose is to eliminate drag when you change table tilt (table tilt unlocked). In other words, the trunnions are always further apart than the width of the table bar measured at the bosses.

David just said that the dollar bill gap does close when he locks his table. I have no doubt that one could increase the gap too far for gap to be closed by the pressure exerted by the locks.

I saw that but that is not what I experience here with my desk top model. With the trunnions 14 1/2" apart and locked with "dollar bills" behing both trunnions - I can remove the "dollar bills".

[algale]

It is a function of how far apart the trunnions are.

The dollar tricks only purpose is to eliminate drag when you change table tilt (table tilt unlocked). In other words, the trunnions are always further apart than the width of the table bar measured at the bosses.

David just said that the dollar bill gap does close when he locks his table. I have no doubt that one could increase the gap too far for gap to be closed by the pressure exerted by the locks.

I saw that but that is not what I experience here with my desk top model. With the trunnions 14 1/2" apart and locked with "dollar bills" behing both trunnions - I can remove the "dollar bills".

Is that desk top model using the board between the trunnions? If so, I don't think it is a relevant. Totally different geometry to put a beam between the trunnions versus attaching a table on top.

I don't understand why but I do understand what you are saying.

I can do the same thing with the table assembly upside down on the work bench - but not tonight. I even have a table that I can do that with and still not touch the go to machine.