Tablesaw alignment thought about a different way

[Don Crawford]

I have jigs, calipers, and dials for this fairly regular job of aligning the table saw blade to the miter slot.

However, for the armchair engineers out there, throw rocks at the following suggestion.

Lets say you remove the blade, loosen what you need to loosen (either the table nuts or the trunions depending on type). Raise the arbor to the top of its travel.

And you have a device which fits on the arbor like a blade (maybe thicker for more rigidity) but it is shaped like an L with a miter bar at the end of the L. Then you would lower the arbor slowly with everything loose until the miter bar is in the slot. Then you would have everything perfectly square and you lock it all down.

Why wouldn't that work?

[Tony Bilello]

That will probably work if you could get the "L" at very exactly 90* and as long as you can get your hands/fingers in where they need to be to tighten everything up.
I don't know if this would be any easier that using a dial caliper. I suggest you make one and see for yourself. then let us know how it went.

[Mike Kees]

I think that in theory this could work. However making this piece would probably need to be done in a machine shop to obtain anywhere near the accuracy needed. Also I cannot see the saw staying in place as it is tightened. With Tony on this one,make it and let us know if it works.

[Don Crawford]

I think that in theory this could work. However making this piece would probably need to be done in a machine shop to obtain anywhere near the accuracy needed. Also I cannot see the saw staying in place as it is tightened. With Tony on this one,make it and let us know if it works.

I am pretty sure I can get this done with a couple bolts and aluminum extrusion I have at home. I will report back.

[Mike Kreinhop]

If you had an old blade that you weren't too fond of, you could drill a hole in it to attach the horizontal bar that mates with the miter track.

[Dan Friedrichs]

All the pieces would need to be ridiculously rigid for this to work. Put a dial indicator on a saw blade while in the saw and push against the blade with your finger - you'll see ten-thousandths of movement. You're typically trying to align a saw to a few thousandths. I don't think you'll get even close to the needed precision (to say nothing about temperature stability, robustness, etc) with aluminum extrusions...

[Frank Pratt]

I don't know that any of the suggested methods would have the rigidity needed for this. It doesn't take much side force to cause a few thou flex in a jig like this unless it was massively strong. It probably takes less than half an hour to get things aligned using a dial indicator & do it old school. Even after making this jig, you still have to do the actual aligning.

Seems like a dubious solution looking for a problem.

[Kyle Iwamoto]

Im an actual armchair engineer. I've used a very expensive production jig to align my saw, and got it close. Nothing but a test cut will tell you if your alignment is spot on. Get close, run some scrap through and adjust accordingly. Your jig, or any of the others will get you close. The final adjustments, run a test cut. Several, I should say. Good luck!

[Andrew Hughes]

I’m trying to figure out what the heck you guys are taking about.
Does that mean I’m not a Engineer

[Bill Carey]

I’m trying to figure out what the heck you guys are taking about.
Does that mean I’m not a Engineer

When you find out Andrew, please let me know. I had no idea a TS could be this complex. LOL

[Andrew Seemann]

All the pieces would need to be ridiculously rigid for this to work. Put a dial indicator on a saw blade while in the saw and push against the blade with your finger - you'll see ten-thousandths of movement. You're typically trying to align a saw to a few thousandths. I don't think you'll get even close to the needed precision (to say nothing about temperature stability, robustness, etc) with aluminum extrusions...

The other thing is that the saw itself doesn't have the rigidity. You'll get flex and slop between the end of the arbor and the top. You can deflect a saw blade by about 5 thousands by just moderate finger pressure. The main thing is that the saw needs to run properly after setup. Honestly, you can do it with just a quality combo square.

When you tighten the corner bolts for the top on a Unisaw with a dial indicator on the blade, you can see it moving by thousandths. Part of the skill/art of setting up a saw is being able to tighten the bolts without throwing the saw out of alignment. That and knowing when to stop adjusting. It is temping to try to set up a saw more accurately than it was manufactured; you spend a lot of time chasing machining tolerances doing that.

[Tom M King]

One year, I needed to spend some money on tools right at the end of the year, and one of the things I splurged on was the Master Plate. I don't know if it's worth the cost, but I was able to get all my table saws dead on with it much easier than trying to use a blade. I would buy one of those before making, or having made, something more elaborate.

http://mastergage.com/display_product.asp?id=4

[Bert McMahan]

You can get a 6" x 12" piece of MIC6 aluminum (super flat) from McMaster for $35 if you want to make your own Master Plate, though at $49 I'd probably just buy theirs since it's got a nice square hole through it already.

[Joseph Quattro]

I have a masterplate bought years ago - I don't remember how much it cost, but have used it for just about every saw I own to good effect.

[Bill Dufour]

Problem is you probably do not have accurate enough measuring equipment to locate the miterbar exactly the distance over from the blade flange. You have to go up 2 inches or so and then over about 6" and measure this within 1/1000 of an inch and then make the jig to that same accurately. I bet the blade flange has more wobble then you think. If you use a blade stabilizer you need to make another jig for that spacing.
Bill D.