Table Tilt Lock

BuckeyeDennis · Post by **BuckeyeDennis** » Sat Nov 08, 2014 10:30 am

algale wrote:Got to assume the .005 gap is split between the trunnions when the clamp is unclamped. Or am I wrong?

That's my understanding as well.

Ed in Tampa · Post by **Ed in Tampa** » Sat Nov 08, 2014 10:50 am

algale wrote:You've got the question wrong Dusty. The question is how one can do a table alignment and end up with the trunnions as far away from the table bar as in your photo. EDIT: Or maybe you've been using a dollar coin rather than a dollar bill for Nick's trick??:D

As I said in one of my posts, I would assume that with the table bolts loosened, applying the tilt lock would drive the trunnions flush to the table bar. That is unless the lock wedge is being held off by the little ledge show in the photo I borrowed from Buckeye and annotated in a prior post in this thread.

Dusty
I have the drilled out trunnion hole and my table locks fine.
By the way my thumb still hurts from being smacked by the trunnion when it broke free of my clamp during drilling. Don't think it will ever be right.

Dusty I would take the trunnions off the table and then reassemble using the parts diagram it almost looks like you have a washer or something on the piiviot beteen the trunnion tie bar for the main supports.

Even loose my trunnion rides closer to the fins than your does locked.

JPG · Post by **JPG** » Sat Nov 08, 2014 11:05 am

Looking done

Well shoot! Fergit to 'submit' this last time!:o

[ATTACH]26763[/ATTACH]

Pix is of a 510 reassembled, but not adjusted table.

Notice the trunions are against the bar pivots.

The clamp assembly consists of a threaded bar, two clamp shoes, two shoe return springs, a washer, a long(coupling) nut and the restrained hand lever.

That is all removed and sets below the trunions in the pix.

The rear shoe is secured(threaded hole) tightly to the rear end of the rod.

The front shoe is free to slide along the rod.

Both shoes are pushed away from the trunion by the springs when the clamp is 'loose.

As the lever tightens the clamping nut it squeezes the shoes towards each other and they both press against the trunions.
I think the pad backing up the trunion contributes only a small amount of resistance to tilting, but is to provide a backing to the rear of the trunion to limit any deflection.

So, if Dusty has that gap between the rear trunion and that backup pad the rear shoe must be interferring with something that prevents it moving all the way up against the rear trunion when the front is 'clamped'. Not understood is why the front clamps at all.

Perhaps the rear spring is broken/jammed in the rear spring bore?

With the clamp nut very loose, the rear shoe should move in/out with rod movement all the way against the trunion. Same for the front shoe in the reverse direction.

FWIW, the trunions are steel(hard) and the shoes soft(aluminum").

The surface area of the contact area of the shoes is reduced by having a raised area at each 'end'.

Sorry for any confusion with this post as initially 'posted'.

dusty · Post by **dusty** » Sat Nov 08, 2014 12:14 pm

algale wrote:You've got the question wrong Dusty. The question is how one can do a table alignment and end up with the trunnions as far away from the table bar as in your photo. EDIT: Or maybe you've been using a dollar coin rather than a dollar bill for Nick's trick??:D

As I said in one of my posts, I would assume that with the table bolts loosened, applying the tilt lock would drive the trunnions flush to the table bar. That is unless the lock wedge is being held off by the little ledge shown in the photo I borrowed from Buckeye and annotated in a prior post in this thread.

Actually, I have not been using a dollar bill at all. I have not used a dollar bill in many, many moons. I use a piece of aluminum foil that I cut from the aluminum vacuum seal on a plastic 1 pound can of Folgers coffee. It measures .003" and I fold it in half for a gap of .006". The foil is tough and resists being torn when pulled out from behind the trunnions after alignment.

This is not an illogical assumption. The problem is simply that is a false assumption. I have done exactly what you suggest. That is why my table is upside down on the bench.

The table bar, measured between the points where it contacts the back side of the trunnions, is 14 1/2" wide. Therefore, when the table alignment is all done, the back side of the trunnions should measure 14 1/5" plus the thickness of the dollar bill shim.

That is not necessarily true. I have confirmed on two tables that if the trunnions are loosened and spread as far apart as they will go locking the table tilt WILL NOT ALWAYS pull the trunnions back to that 14 1/2" separation. The front trunnion moves to that point but the rear trunnion does not always do so. Thus the gap. You might not be able to ascertain this from the pictures that I have posted but the gap is always on the rear trunnion.

JPG · Post by **JPG** » Sat Nov 08, 2014 12:24 pm

dusty wrote: . . .

That is not necessarily true. I have confirmed on two tables that if the trunnions are loosened and spread as far apart as they will go locking the table tilt WILL NOT ALWAYS pull the trunnions back to that 14 1/2" separation. The front trunnion moves to that point but the rear trunnion does not always do so. Thus the gap. You might not be able to ascertain this from the pictures that I have posted but the gap is always on the rear trunnion.

I think you have discovered that if the trunion bolts are tightened with the trunions not against the bar pivots, the clamp will not overcome the retaining bolts and move them so.(at least on yours!)

I think the rear trunion not moving is another indication that the rear shoe is not moving against the trunion. i.e. what ever is causing that lack of motion is causing the gap when tightened.

Something is interfering with the rod and shoe moving towards the rear trunion.(towards the front of the table).

algale · Post by **algale** » Sat Nov 08, 2014 12:32 pm

JPG wrote:I think you have discovered that if the trunion bolts are tightened with the trunions not against the bar pivots, the clamp will not overcome the retaining bolts and move them so.(at least on yours!)

I think the rear trunion not moving is another indication that the rear shoe is not moving against the trunion. i.e. what ever is causing that lack of motion is causing the gap when tightened.

Something is interfering with the rod and shoe moving towards the rear trunion.(towardsa the fronr of the table).

Or the rod is too long, or the threads at the rear of the rod for the rear wedge don't extend far enough or the threads tapped into the rear wedge are too shallow....

BuckeyeDennis · Post by **BuckeyeDennis** » Sat Nov 08, 2014 12:39 pm

dusty wrote:Actually, I have not been using a dollar bill at all. I have not used a dollar bill in many, many moons. I use a piece of aluminum foil that I cut from the aluminum vacuum seal on a plastic 1 pound can of Folgers coffee. It measures .003" and I fold it in half for a gap of .006". The foil is tough and resists being torn when pulled out from behind the trunnions after alignment.

This is not an illogical assumption. The problem is simply that is a false assumption. I have done exactly what you suggest. That is why my table is upside down on the bench.

The table bar, measured between the points where it contacts the back side of the trunnions, is 14 1/2" wide. Therefore, when the table alignment is all done, the back side of the trunnions should measure 14 1/5" plus the thickness of the dollar bill shim.

That is not necessarily true. I have confirmed on two tables that if the trunnions are loosened and spread as far apart as they will go locking the table tilt WILL NOT ALWAYS pull the trunnions back to that 14 1/2" separation. The front trunnion moves to that point but the rear trunnion does not always do so. Thus the gap. You might not be able to ascertain this from the pictures that I have posted but the gap is always on the rear trunnion.

This says to me that we shouldn't rely on the brake shoe clamping alone to make the "coarse adjustment" of positioning the trunions up against the table bar. There is a large offset between the brake shoe and the table/trunnion bolts. Thus the force from the shoes wants to tilt the trunnion, as well as slide it. That tilting action will want to lock the trunnion to the table, even if the bolts are loosened slightly. I have some old bar clamps where the head is held in position on the bar using this exact same principle -- they have no locking mechanism whatsoever except for friction and the offset force from the clamp screw, and they lock up just fine.

If you "help" the trunnions get into the correct position before tightening the clamp, do the table mounting holes provide enough clearance?

dusty · Post by **dusty** » Sat Nov 08, 2014 2:53 pm

I still have not resolved the table tilt issue but I do believe I am making progress. I do believe that when a table slips it is because the brake shows have not fully engaged (the gap). What is preventing that engagement is still to be determined.

The circled areas in the attached images may (repeat may) be an issue or at least an indicator of the issue.

[ATTACH]26770[/ATTACH]

[ATTACH]26771[/ATTACH]

dusty · Post by **dusty** » Sat Nov 08, 2014 3:00 pm

JPG wrote:Shhh! Maybe Ed will miss this thread!:rolleyes:

That gap looks bigger than what I would attribute to the 'hole enlarging'.

This gap was created by deliberately sliding the trunnions apart as far as they would go (with the four trunnion bolts loose) and then securing the tilt lock. The front shoe is making contact with the trunnion while the gap remains as shown on the rear trunnion.

Why the rear shoe is not pulled into place is now the question.

algale · Post by **algale** » Sat Nov 08, 2014 3:10 pm

dusty wrote:I still have not resolved the table tilt issue but I do believe I am making progress. I do believe that when a table slips it is because the brake shows have not fully engaged (the gap). What is preventing that engagement is still to be determined.

The circled areas in the attached images may (repeat may) be an issue or at least an indicator of the issue.

[ATTACH]26770[/ATTACH]

[ATTACH]26771[/ATTACH]

Aren't those the same points Buckeye ID'd as suspect earlier and I annotated when I borrowed his photo? EDIT: No they are not.

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