Dial Indicator Jig

[Russel Tauras]

Hi,
I’m making a dial indicator jig for my table saw and I’m using ¾” aluminum bar stock to ride in the miter gauge slot. I need to sand the aluminum bar stock down to fit the slot on my table saw.

What’s the best technique for sanding my aluminum bar stock?
What grit sandpaper should I use?

Russ

[Ben Cadotte]

Grit is determined by how much you need to remove. If its just a little bit. A fine paper will get you there. Just make sure what ever paper you use on the aluminium not to use it again on a wood project.

If you have a flat file I would use that versus sandpaper.

[Bruce Page]

I'd use 220 or 280 wet & dry paper.
It will remove the alum quickly but you’ll be able to easily control how much.

You could use a hand sanding block or tape the paper down to a flat surface like your table saw.

[Cary Swoveland]

You could of course make it a tad less than 3/4", and drill and thread holes width-wise for set screws (or buy an Incra miter slider for about $20, if it would work with your jig).

Cary

[Jordan Shatsoff]

I was trying to figure out how to make a jig this weekend.

Instead of going through the trouble though I found it much easier to just use the hole in the bottom of my dial indicator and attaching it to my miter gauge (incra v27). I used the hole in the miter gauge where you usually attach the sub fence.

It of course requires having a loop on the bottom of your dial indicator (the ones with magnetic bases usually have them I think). I was using it for the fence, but the same idea would work for the blade. If it ends up not reaching the blade, then a simple modification would be to attach the dial to a board (or some of your aluminum bar stock) using the same hole, and then attaching the board to the miter gauge, just like a fence.

Or course I didn't really answer your question.

[Greg Peterson]

I removed the base of my Delta tenoning jig and attached the magnetic base onto that. Works pretty good.

[Russel Tauras]

Sandpaper worked like a champ!

Only took 5-min. Used 400-grit.

Bar measured 0.7572 before and 0.7535 after.

[Russel Tauras]

Well, it’s done. It’s just a first proto.
Only took me a couple hours of work total.

Got the dial indicator from Grizzly.
The 6” aluminum bar stock was only a $2.
I tapped 2 10-32 threads in the bar stock.
The rest is MDF.

Measured my blade heel at 0.002 from left gauge slot.

My fence has a deflection of 0.0165 from top to bottom when locked down. That’s more than a 64th. I would imagine that’s pretty bad.

Blade runout was 0.002.


Russ

[Jacob Reverb]

Russ,

I wouldn't worry too much about 1/64" on your fence...if I understand you correctly, are you saying that the surface of your fence is not square to your table? If so, that's no huge deal, though getting 1/64" out might be tricky depending on your fence.

What do you see if you put a good square on your table and put it up against your fence? Does it look good there?

If so, I would call it macaroni and go cut wood. These dial indicators, once you begin to believe them, can drive a man to drink. I'm not sure such precision is needed for woodwork.

Jacob.

[Russel Tauras]

Well…
I just checked a square against my fence and it’s not square to the table. I “see light” between the square and the top of the fence.

What is the issue with this? What error will I see in my cuts?


Russ

[Joe Chritz]

Probably won't see any. The index of the material is generally on the table top, not the fence. The length of the piece being cut will be controlled by the narrow section at the bottom.

If it was out the opposite direction it would be a longer piece if it only hit the bottom by however far out of square to the top it was.

If you have a piece that uses the fence to index from then it could toss it out a lot.

I don't think I have ever even checked that dimension.

Joe