Please help with table saw alignment puzzle

[Tony Zona]

Aligning my Delta contractors table saw turned into a puzzle.

I aligned this saw a long, long time ago, only to discover just recently that I must have done something terribly wrong because I recently could not rip 45 degrees with the original throat plate. The blade teeth would hit the original red throat plate. I figured I apparently had moved the entire trunnion to the right out of ignorance.

I spent the better part of Friday through Monday aligning, and that’s too long a story to write about now. I even got the 45 degree rip aligned, which surprised me. I learned about this part of the alignment only recently. When I checked it last week, the 45 degree rip had been out by more than a blade width before I started. Clearly I have not used the saw to rip 45s or I might have noticed.

This alignment ultimately involved having to remove the rear trunnion and elongating the bolt holes to allow a lot more movement to the left. (I forgot to write down how much I increased the lateral hole size with a die grinder.) I also had to disconnect the blade tilt wheel to be able to move the front of the trunnion more to the left, also.

I would like the thoughts of those of you who have experience in this alignment.

The blade is now within a couple thousandths parallel to the miter slot in both 90 degrees to the table and 45 degrees. That part was a success, and maybe even a fluke to get it that close. And . . . the saw blade rises exactly into the zero-clearance throat plate I had before all the aligning.

But the blade teeth still touch the original red throat plate and cannot cut a 45 rip.

How did I go through all this and end up in the same place?

Of course, though, I will make a 45-degree throat plate like I already had for 90-degree cuts. If I would have done that at the start I would not have known about checking the blade alignment for 45-degree rip cutting. So, I’m thinking I have an overall gain, but still a puzzle.

[Bruce King]

Maybe the saw was supposed to come with a 45 throat.
Or, being a contractor saw you just saw through the same one.

[glenn bradley]

The fact that you got a contractor saw that close at 90 and at a bevel is wonderful. I would be hard pressed to even roll the saw across the floor if I got things that close on a saw with the motor hanging out the back. I would use your current throat plate to make another ZCI and cut a wider slot into that. I cut the wider slot I required using a straight bit and the router table but, a jigs, keyhole saw or other method would also work. If you use a smaller diameter blade you can start a slot with the saw at 45*. You can then swap blades and finish the cut resulting in a 45*zci. The downside is that it is only good for 45* and nothing in between. A wide slot has served me better.

ZCI (1).jpg

[Bill Dufour]

Due to geometry the blade body moves over as it tilts. You should make a 90 and a 45 degree plate to keep it close to zero clearance. the only way it would not shift over is if the tilt axis is centered on the table top. Watch a
teeter-tooter in action to see the geometry in action.
Bil lD

[Tony Zona]

I agree, Glenn, getting that close is remarkable. I measured repeatedly. It was a fluke for sure. I expect when the temperature changes, the alignment will move. i will have to watch it.