Making a 70.6 cut on miter saw

[-MIKE-]

What an idiot. Do *YOU* see a 70.6 degree setting on that fence?

[Steve Turner]

> What an idiot. Do *YOU* see a 70.6 degree setting on that fence? No, but it's BIG. And it's a FENCE. And it's really awesome, and... what the hell were we talking about again? :-)

[Swingman]

Crocodile Dundee ... how soon we forget! ;)

[Steve Turner]

Rawight! :-)

[Robatoy]

[J. Clarke]

>>> What an idiot. Do *YOU* see a 70.6 degree setting on that fence? It has a 70.5 degree stop and can be fine tuned from there.

If you gotta have 70.6 actually marked on the gage you need a 1000SE or

1000HD, both of which have 1/10 degree verniers.

[-MIKE-]

>>>>>> What an idiot. Do *YOU* see a 70.6 degree setting on that fence? >

Did you look at the picture? :-)

[HeyBub]

When faced with a new problem, it is often helpful to reduce this new problem to a problem that has already been solved.

Tell me, have you ever made a 35.3° cut with a miter saw?

[Leon]

Nevermind the answer to that question, how did you make the degree thingy show up after the 3?

[Tom Dacon]

Well, of course it takes much less time to do it than to read about it. I gave a detailed explanation of the process, so that someone using it would have an understanding of what was going on, rather than just following a cookbook. In practice, it takes no more than a minute or two to lay out the angle and set the miter gauge.

I wrote the procedure from my own experience and my own practice in the shop, not from something I read in a book (although I learned trigonometry from a book, of course, back in high school). For most shop requirements, the fixed-stop miter gauges like the Kreg and the Incra and their like do a fine job - quick, accurate, and repeatable. I use one myself. But when they can't do the job, as in the case of the OP, you have to have some other way to handle the problem, and the one I described is both simple and accurate. You just have to read it with an open mind, preferably in the shop where you can try it out and prove to yourself that it works.

By the way, while I didn't mention it in my post, if you have to do an angled cut on a large panel this procedure is almost essential for an accurate cut. In that case, you lay the angle out right on the panel, clamp a straight-edge, and make the cut with a circular saw. Because for long runs the procedure is sensitive to the accuracy of the perpendicular line, I would strike it using the beam compass method, with a modified version of this technique:

or by the well-known technique of flipping the square and splitting the difference. You could, if you liked, trust the squareness of the panel, but I don't. After you have an accurate perpendicular your accuracy is assured.

Tom

[Leon]

Actually, ;~) just so we are clear, it takes less time to make the set up and make the cut than simply saying this,

Put your wood on the mitersaw 90 degrees to normal, adjust miter setting to

19.4 degrees and make the cut.

[Swingman]

Or graphically speaking:

Just kidding ... dejavu all over again, I gotta get back to work. :)

[Leon]

Mutt'n Jeff?

[Robatoy]

What degree thingy?=B0

[Tom Dacon]

Leon, maybe you're missing my point. What I have been describing is an accurate method to get the exact 19.4 degrees, not what you do once you get your miter gauge set to it.

Tom

[Martin H. Eastburn]

What you need is a "Precision Universal Bevel Vernier Protractor"

lot of times you can find these in pawn shops. Set this to the angle and align the saw blade and table to the blades. A model 360 (non vernier) would be very good. Vernier version Is best! New it was $250. Something like it in plastic and lower in precision can be had at office suppliers. This one is rated at 1/12 degree with vernier.

Mart>> Put your wood on the mitersaw 90 degrees to normal, adjust miter setting >> to

[Tom Dacon]

You nailed it, Martin. That's the kind of thing I was talking about.

Early on in this benighted thread I talked about using a protractor as a tool to solve a problem which as the original poster posed it was to measure an arbitrary angle to the precision of a tenth of a degree and make a suitable cut. Machinists are accustomed to solving problems like this, and consequently they have the tools to solve them. If a machinist gets an angle called out as 70.6 degrees, he understands that he needs to produce an angle between 70.55 and 70.65 degrees. He HAS to produce an angle to that measurement and those constraints. This is a nice tool, Starrett as you might expect, and well within the constraints of the problem. I have a slightly less accurate machinist's protracter of my own, but I'm going to be on the lookout for one of these. Thanks for the tip. I hope we don't end up in a bidding war :-)

Glad to see someone here who doesn't have something to prove :-)

Tom

[Tom Dacon]

Well, at least there's SOMEONE here with a sense of humor.

A mathematician knows that rule: problems are either trivial (we know how to solve them), or hard (we don't).

As it happen, maestro, I HAVE solved this one. Not this exact one, of course, but once in the distant past I had to cut an angle of

2.35333333333333333 degrees, and I made a template from it. All I have to do is produce twenty-nine exact duplicates of it, stack them up on the miter gauge, and I've nailed this 70.6 degree problem.

So what else have you got for me?

Tom

[J. Clarke]

>>>>>>>>> What an idiot. Do *YOU* see a 70.6 degree setting on that fence? >>

Did you read the manual?

[J. Clarke]

FWIW, Grizzly has a dial protracter readable to 5 minutes for 40 bucks and a digital readable to .1 degree for 90. Not Starrett quality of course but should do most hobbyists just fine.