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

Okay, lets go over the internals of a Delta UniSaw.

This might be kind of basic, but it's good info to be certain of. The basic concept and terminology is common to many, if not most, table saws.

Here's what a UniSaw looks like with the top off.

A couple disclaimers here,

1. Sorry about the clarity of the picture. If you cannot read all the labels, the following link should be clearer, but much larger.
.BMP file of the same picture

2. The arbor bracket in the picture does not have arbor in it - obviously and is not fully mounted. It is just in the photo to show you where it mounts.

As you can see it's a pretty basic concept.

Two trunnion brackets (front and rear) have half moon "tenons" or ridges.

Two trunnions (front and rear) have half-moon shaped "dadoes" that mate to the trunnion brackets.

The two trunnions are held together by bolting to a heavy, solid cross member called the yoke.

The yoke is heavy enough that it supports a large, steel shaft. From this shaft hang both the motor via the motor mount bracket and the arbor bracket.

This whole assembly hangs inside the cabinet from the ears on the front and rear trunnion bracket.

The arbor bracket and the front trunnions have teeth milled in them. These milled teeth engage worm gears on the tilt shaft and elevation shaft. Rotation of these shafts cause movement in their respective parts.

Let's take a look from a different perspective

Here is the same assembly without the cabinet. The motor has been removed as well as the arbor bracket.

And here is a view of the front 'sandwich'. The front trunnion bracket, front trunnion and yoke. Here you can see the end of the tilt shaft. Note how only a portion of the front trunnion is riding on the worm gear.

Note the motor mount bracket - the motor mounts with the bolt that is present and with a pin that slides through the motor mount in the empty hole. We'll see that system eventually.

Finally here is a shot of the saw guts assuming you were sitting inside the cabinet, on the floor, looking towards the operator position.

Nothing all that awe inspiring here, but thought you might enjoy the shots without the cabinet.

Now that you have a feel for the primarily fixed components, pretend I just put the arbor bracket back on.

Here the arbor bracket is in the UP position. Note the three arrows. The one on the lower right shows the elevation worm engaged with the arbor bracket. This shaft extends through the front of the saw and is turned to raise and lower the arbor bracket and of course the blade.

The blade stops going up, when the notch on the arbor bracket, indicated by the arrow, stops on the worm gear.

I use the other two arrows so you notice the motor mount bracket and the key way that secure the arbor bracket to the mounting shaft.

The view is not from quite the same angle, but here the blade/arbor bracket is almost all the way down. Note the motor mount bracket has rotated down as well.

The motor moves in conjunction with the arbor bracket. A lot of folks think that by removing the belts that the two move independently. They do not. The keyway in the previous two pictures secures the arbor bracket to the shaft, a roll pin secures the motor mount bracket to the shaft.

Failure to realize this causes a lot of folks trouble on disassembly as they try to remove the arbor bracket with the motor weight still present.

I also show this picture to show a vulnerable spot on the arbor bracket. Remember where Blankmans arbor bracket had been broken. See where this arbor bracket is protruding into the front trunnion bracket. People overlook this sometimes and cause a fracture of the arbor bracket trying to remove it.

We can take a quick look at some of these parts individually.

Here is a motor mount bracket that has been removed. This bulky looking piece is actually hollow. The long roll pin sticking out is the pin that secures the bracket to the shaft.

Once in a while you see a casting that has failed at the bolt hole or motor mounting pin hole. The part is cheap enough used, but a serious pain to replace.

This bracket hangs from this shaft, which is driven through the motor mount bracket and the yoke with a portion hanging out to receive the arbor bracket.

The only thing to know here is that there are two bearing load springs inside. They go on the shaft, between the motor moung bracket and the yoke on the blade side. My best thought is that they are either to alleviate any potential 'slop' or to keep the two parts from binding on each other.

Rear Trunnion

The next two pictures are of the rear trunnion.

Not much to go wrong, but a couple things to notice. The copper colored hole is just that a hole with a brass bushing. It supports the rear of the elevation shaft. This bushing is sometimes called a bearing. Either way, there is very rarely any reason to do anything with this bushing. If it is round and present, it probably is fine for our purposes. Unless there was noticeable play in the shaft when you removed it, just leave this bushing alone.

The red lines in the second picture are to point out mounting points for guard mounting brackets.

The two small holes usually are used to secure a small bracket that the front mounting position of blade guard, the round hole mounts a steel rod that sticks out the back of the saw. The rear of the blade guard mounts on this rod.

Both the rear trunnion bracket and the cabinet have a small 'quarter - moon' relief to allow this rod to move when the inner workings are tilted. (go back and look if you don't believe me

)

Periodically I get person looking for a guard mounting bracket with 'off-set' holes. So evidentally at some point in time, one or both of the smaller holes were moved. I looked today, but could not find a rear trunnion that differed from the rest.

The rear trunnion bracket

Well there isn't much exciting there. You would think that the 'ear' would be prone to breakage at the point where it narrows.

And they do, but not near as often as the front trunnion bracket.

This part is very simple and fairly bullet proof.

To be continued on the next post . . .

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