WoodNet Forums: Re: Anybody want to build a UniSaw?

Okay, here we go again.

Thursday and Friday were raining/stormy here so working outside on the cabinet came to a stop. Today was nice, but the kids were outside playing while the wife was at work so . . .

I decided to switch to an interior part. I did try a chemical stripper on the cabinet, but more on that later.

Trunnion Bracket

A trunnion bracket seemed like a good part to tear down today with kids coming in and out of the shop. I selected this beast!

It's an older bracket, as noted by the casting mark on it. The LTA stands for Light Duty Tilting Arbor, the number 408 just refers to the arbor bracket. At least I have always assumed that's what the LTA stood for.
These brackets remained the same up through the saws that I am familiar with of early 80's vintage.
This one looks rough cosmetically but the teeth are there. The two 'open' spots on each side of the teeth are supposed to be there. It is also very common to find a partial tooth for the first tooth.

On the left side of the picture, the 7/8" nut is on the end of the arbor (the opposite of the saw blade end). Under it is a special Delta lockwasher, under that the outside bearing. Surrounding that is the bearing retaing nut or ring, which pins the bearing into the bracket.

These nuts are often difficult to remove, so enter our friend PB Blaster again.

A trick showed me over the years is to use a 'blow gun' on the end of an air hose to assist the penetrating agent to penetrate.

We give this a good soaking to help free up both the bearing nuts.

While that soaks we can pull the arbor nut and blade washer off.

Who knows? Under the blade washer was a shop made shim washer of the same diameters.

Ya can never tell what you will find. Last week I found an arbor bracket that had been modified to position it for a 12" blade and the arbor had a homemade adapter changing it to 1" bore.

Anyway . . .

This is the first way I try to remove the first nut. A @#$F%Sman Strap Wrench and a 7/8" socket/ratchet.

And hey this one comes right off. If it won't come loose, we move to the vise and clamp just the pulley. You have to be carefull to pad the vise with wood blocks of soft pine or such and then clamp down hard on the pulley to secure it.

Another way is to place a wrench on the flats behind the arbor flange. I just don't have a wrench that is comfortable enough to do that easily.

After that nut, there is a special Delta lockwasher. This washer needs to be coaxed out. Don't pry it hard, turn the bracket upside down, shake it lightly and wiggle it out. If you need a little more space to get your fingernails on that washer, then go ahead and remove the special bearing retaining nut.

Use a blunt drift pin or punch.

Place the punch in one of the two notches and lightly tap with a hammer. I'm sure there is a Delta spanner wrench for this task, but I can't seem to get one.

Don't Use a Srewdriver for This Step

If you do, sure as tar you will have a nut that is firmly seated. If it is, you will quickly tear into the nut with the screwdriver and ruin it. If you ruin both slots we are going to play heck getting this nut out. It can be done, but it adds a fair amount of work.

The Lockwasher

Here's that lock washer. It's a washer with an ear that rides in the keyway so that the washer turns with the arbor and isn't tearing up the threads and such.

The washer has a curved shape to it. It's supposed to be that way.
Often times one side of this washer is 'folded' up agains the inner nut as a way to keep the nut from spinning off. This one was not that way, but that's the way we'll do it when we reassemble the arbor bracket.

Speaking of keyways . . .

The arbor pulley is secured to the arbor with a piece of keystock and either one or two set screws. This older pulley has one set screw. If it would have had two they would be in line on top of the keyway in the two outer sheeve grooves. You can just loosen it or remove it all together.

Often these screws have a bit of locktite on them. I have ruined a number of allen wrenches removing these.

This one breaks free with just a T Handle wrench, but a socket driven hex head is nice for this step. I just keep breaking them.

If you forget this, and I have, when you go to press the arbor you will fight it the whole way and can score the threads on the way out.

Here is the bracket prior to moving to the press. We will be supporting the bracket at the red arrows and pushing the arbor out and down.

The small holes in the arbor pulley are 'balancing' holes opposite the set screw hole.

The bracket needs to be firmly supported.

This is a way that I commonly do it. The cast iron press plates are brought as close as possible, then two steel plates are slip into place. They are thin enough to slide into the space betwen the arbor bracket and arbor flange, where the arbor flats are.

I usually press the arbor with the punch stand, then reset and use a steel pin to press the rest of the way.

Tonight however, this arbor refuses to move. We built pressure until we bent the handle on the hydraulic jack.

If we had not supported the bracket carefully we surely would have broken it. As it was, there was measureable flexing of the bracket itself.

So we apply more and more penetrating oil. Several other tricks are tried.
We use a long thin punch pin to tap the keystock once or twice to help free it.

We remove the set screw completely and apply penetrating oil there as well, but no luck.

The bracket is removed and struck sharply with a pin and a hammer to see if sharp force will free it. But no luck.

Resist the urge at this point

to beat on the end of the arbor with a hammer. Don't do it. Only a whack or two flares the end of the arbor enough that it won't clear the bearings and the nut won't go back on it. This will require a trip to a machinist.

Do what I did. Come inside and have ice cream with the family.

Tomorrow as time permits we will try supporting the pulley instead of the bracket, we might try combinations of heat and cold, we might try immersing the whole assembly for a couple days and move on to another part of the project.

We'll also followup on the cabinet and what looks like be a trip to an electroylis bath after all.

Nite all.

Chris

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I may be wierd now, but I'm saving to be eccentric.

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