Digital Angle Gauge

[sheldon.mandel]

Lee valley also sells a strap-on level for posts - not metal, but you could rig something it also works well

shelly

[J. Clarke]

Care to post your design somewhere?

[Lew Hodgett]

What part of a 9 ply Birch triangle would you like me to post?

[J. Clarke]

The dimensions for openers, and a photograph of it in use.

[Lew Hodgett]

Sounds like you need to go back and taking drafting 101 or is it CAD

101 these days?

In either case, take a hike.

Lew

[J. Clarke]

In other words you didn't make the thing you claim to have made.

[Lew Hodgett]

See if you are up to this for starters? ====================================== A^2 + B^2 = C^2

A = C(Sin "a") = Altitude of triangle B = C(Cos "a") = Base of triangle C = Hypotenuse of triangle "a" = Desired angle

Select angle "a" and hypotenuse length, then calculate results.

Layout triangle and trim to size. ====================================== Are you that damn lazy or just plain dense?

Lew

[J. Clarke]

That is not a picture of the device you made and used being used to set the blade on a table saw.

[Jack Stein]

Might as well post all 180 of them for 1/2° steps between 0° and 90°. Then, you only need to build a new one if you want something other than

1/2°.

[Jack Stein]

I'd hope everyone with half a brain is that "lazy". That's why millions of tools are sold to measure and set angles...

[Father Haskell]

Accuracy typically claimed at what, 1/10 degree?

How heavy is "relatively heavy?" Heavy enough to deflect a tilted blade a few tenths of a degree?

[CW]

I like the way you think.

[Upscale]

They claim accurate to 0.2°.

I figure close to a pound. I suppose under the right conditions (or wrong conditions in this case) the weight could have an effect on degree angle, but considering all the possible variations one is going to encounter when working with wood, I'd guess any deflection effect is going to be negligible in the grand scheme of things.

[Upscale]

And, I forgot to mention one other consideration. For a woodworker, this digital angle gauge has immeasurable toy value. I figure there's hours and hours of play potential incorporated into it. :)

[Lew Hodgett]

-------------------------

Seems you must have found one. BEG

Yep.

Lew

[Father Haskell]

Gotta be real careful whenever I'm using a dial indicator on a blade (1/8" kerf, standard, thick plate). Seems like a pound force against the side will flex it a good 10 thou or better.

[J. Clarke]

I doubt that one can cut one of Lew's plywood triangles to that kind of precision.

[basilisk]

when I worked in a furniture plant, many years ago, we used flat machined plates, 1/4 inch thick, mounted on the arbors to do our initial setup and that eliminated blade runout and problems avoiding the teeth during setup.

basilisk

Gotta be real careful whenever I'm using a dial indicator on a blade (1/8" kerf, standard, thick plate). Seems like a pound force against the side will flex it a good 10 thou or better.

[Tom Veatch]

...

.010 (ten thousands at the end of a 5" radius equates to about 0.1°. That's within the claimed accuracy of the gauge.

Generally when I use the gauge, the blade is near it's full elevation, the tilt angle is never more than 45°, and the gauge CG is more like about 2.5 inches from the arbor. So instead of a pound acting normal to the blade at the outer edge, the worst case would be a pound acting at 45° to the blade 2.5 inches from the center. That's only about 35% of the bending moment generated by 1 pound normal to the blade at the outer edge.

Haven't ran an experiment to measure the deflection, and I may do it, but I don't think it's going to cause any serious error in the location or angle of the cut - unless, of course, you're one of the woodworkers who works wood to tolerances the rest of us can only dream about.

Tom Veatch Wichita, KS USA

[Tom Veatch]

Well, now I have run the experiment.

1. My Beall Tilt box, on a set of postal scales, weighs 6.9 oz.
2. The saw blade is a thin kerf Freud rip cut blade. I don't know/remember the model number, it's just the one that was on the saw when I went to the shop to run the experiment.
3. Tilt angle = 45° according to the Tilt Box.
4. Dial indicator set perpendicular to the blade at a point about 4.5" from the arbor centerline with the indicator zeroed.
5. Tilt Box magnetically affixed to the blade directly above the arbor and butted up against the inside edge of one of the teeth - as far from the center of the blade as it could be positioned to maximize the deflection..
6. Several measurements taken at various points around the perimeter of the blade (no, I didn't count them, nor did I record individual measurements or their relative angular locations around the blade).

Caveats:

1. Dial indicator calibration traceable to the Bureau of Standards is not available. Dial indicator is the one that came with my "Align-It".
2. Angle between the Dial indicator plunger and the plane of the blade was eyeballed with reference to a small (2") machinist's square.
3. Calibration of the square traceable to the Bureau of Standards is not available.
4. Blade was not supported to prevent deflection affecting the angle measured by eyeball in 2. above.
5. Location of the measurement point identified above as '4.5" from the arbor centerline" was eyeballed as about 0.5" from the outer perimeter of a 10" saw blade.
6. Any other nits relative to rigidity and deflections in the dial indicator mounting, accuracy of the indicator, and any others you can think of, are your's for the picking.

Results:

All deflection measurements relative to the unloaded blade fell within the range of 0.0015" to 0.002".

Precision:

Only God knows.

Conclusion:

A tempest in a teapot and not worthy of further concern.

Tom Veatch Wichita, KS USA