Skil Digital Angle Finder: huge mistake!

[Doug Miller]

Because to cut an angle of 75 degrees, you set the gauge on the saw to 15.

[-MIKE-]

Doug, I agree. It's a funny saying. It's mine, now. :-)

[-MIKE-]

Right, that's why it would display that on the obtuse side. I'm thinking it's correct, but could still use some options for the display.

[Tom Veatch]

Please ignore, major brain fart! Most days I understand that an angled cut across a straight member produces supplementary angles instead of complements. Only excuse I can offer is that maybe I was thinking of compound mitering crown molding where sometimes you keep the piece on the right and other times the piece on the left.

Tom Veatch Wichita, KS USA

[Tom Veatch]

Kinda made it up to so that it defines the setting on the miter gauge necessary to cut the angle, which, as you stated, is the complement of "1/2 the included angle" = 90 - 1/2 the included angle.

I guess we need to define exactly what we are talking about when we say "miter angle". The "miter angle = 1/2 the included angle" definition gives the angle of the cut measured from the "long axis" of the board which is essentially useless when setting up to make the cut. The "miter angle" that has to be set on the saw or miter gauge is measured off the "short axis" of the cut.

Set the miter gauge (miter angle?) to:

0° for a square cut (180° included angle => 90° - 180°/2 = 90°) 22.5° for an octagon (135° included angle => 90° - 135°/2 = 22.5°), 30° for a hexagon (120° included angle = 90° - 120°/2 = 30°) 45° for a rectangle (90° included angle => 90° - 90°/2 = 45°)

Tom Veatch Wichita, KS USA

[Tom Veatch]

I think the confusion is in the definition of "miter angle". If the

45.5° angle is measured from the "long side" of the board to the cut line, then yes, your corner will be at 91°. But the setting on the saw/miter gauge to make that cut is the complement of that angle. In other words, the "miter angle" you set on the saw/miter gauge is measured off the square 90° cut. So to get a 90° square cut, the saw/miter gauge is set to 0° (which to me is a "miter angle" of 0°)

To get the 45.5° angle on the cut piece, the "miter angle" setting on the saw or gauge would be 90-45.5 = 44.5

I may be swimming against the stream on that definition, but the "miter angle" definition that is most meaningful to the guy setting up the cut is the "angle you have to set on the miter gauge" to get the angle needed on the workpiece.

Tom Veatch Wichita, KS USA

[dadiOH]

Praise be and hallelujah! At last...

[dadiOH]

Right. Please note that is what the gizmo under discussion does...tells you to set as you said.

[Doug Miller]

No, it's not. As described in the original post, that is what the gizmo under discussion does _for obtuse angles only_; for acute angles, it reads the actual angle, not the necessary gauge setting to cut that angle. [*]

And *that*, my friend, is why it's a useless POS. To make use of it, you must remember (a) that whether the reading represents the gauge setting or the actual miter angle depends on whether the corner angle is acute or obtuse,

*and* (b) which way is which. It's much less effort, and much less error-prone, to simply measure the angle with a protractor and do the calculations. [* Quoted from the original post: "... If the angle of the corner is 89 degrees, the miter reading displays 44.5 degrees. But if the angle of the corner is 91 degrees, the miter reading also displays 44.5 degrees. ..."]

[-MIKE-]

I still contend that the little chip (which any computer programming freshman could do) should offer options for the user, depending on which way they want to measure the angle.

My 12" CMS goes to almost 50 degrees in both directions, which enables me to handle many slightly obtuse (carpenter was hungover) corner trim pieces.

[-MIKE-]

And I think most of our CMS's can account for at least a few degrees obtuse.

[-MIKE-]

Cool. My CMS goes 0-48 in each direction (with a nudge, I can get about

51). I saw one, once, that had another scale 90-180 underneath, which I thought was way cool.

So with most not-on-purpose out-of-square corners, I can handle just cutting the corner angle in half.

[dadiOH]

Carpenter didn't have one of those handy gizmos like you do (or, he hocked his square); rocker was hungover :)

[dadiOH]

As you quote, if the angle is 89 the reading is 44.5...that's an acute angle and it tells you to set the gauge at 44.5. Seems right to me. _________

There is hope for MIKE, none for you... :( ___________

[Doug Miller]

I guess that's why we disagree: because you don't realize that while that

*seems* right to you, it's *not*.

Suppose you want to cut a right angle (90 degrees). What do you set the miter gauge at? Zero.

That's because miter gauges do not indicate the actual angle being cut; they indicate the angle's offset from 90 degrees. So to cut an angle of 44.5 degrees, you set the gauge at (90 - 44.5) = 45.5 degrees.

In any event, it should be clear that if the device reads 44.5 for *both*

89-degree and 91-degree corners, then one or the other of those readings *must* be wrong.

Needless to say, I disagree. It's clear that you have a fundamental misunderstanding of the geometry involved.

Do you maintain that both of these readings are correct?

[dadiOH]

Right. And that's where the gizmo would tell one to set it. ___________

Right

Nope, both are correct.

Let's exaggerate the corners a bit...make one 100 degrees, the other 80. In both cases the gizmo will tell one to set the gauge at 10 degrees, right? OK, lets set the gauge there and cut a piece of wood. We now have two pieces of wood and each piece has one corner that is 10 degrees and another corner that is 80 degrees, right? So where's the problem? _________

Well, I aced Euclidean geometry, did less well at analytical geometry (in my defense, the prof was a Yugoslav and *very* hard to understand).

Yes. Setting the miter gauge at those settings will give a correct cut in each case, you just have to orient wood to blade properly; i.e., swing the gauge clockwise or counter-clockwise to get what you want. That or use the offcut for one corner. Try drawing it out on paper.

[Doug Miller]

Yes...... but there's still something you're missing.

Perhaps this will help: suppose you want to cut a 60-degree angle. What do you set the miter gauge at?

Impossible. Think about it: how could you fit both an 89-degree outside corner, *and* a 91-degree outside corner, with the same pieces???

Wrong. It would read 40. Refer to the description from the OP quoted below.

Wrong. Each piece has one corner that's *100* degrees and one corner that's 80 degrees (and, obviously, two corners 90 degrees each, on the ends away from the cut). And when you flip one over and put the miters together so as to fit an outside corner, they _will not_ fit a 100-degree corner.

I leave it to you to determine what angle outside corner they _will_ fit.

ISTM that you misunderstand the purpose of the device. As described by the OP, it appears to be *intended* to display the miter angles necessary to fit two pieces of wood around an outside corner; you certainly won't achieve that in the manner you describe.

That evidently was a long time in the past.

I have an alternative suggestion for you: construct an object with 80-degree and 100-degree outside corners, cut four pieces of wood according to your own descriptions, and then try fitting them around those outside corners. That should be a more than ample demonstration to you of exactly where your misunderstanding lies.

[dadiOH]

Wait...I answered too quickly.

On my table saw miter gauge I would set it at 90 degrees. On my radial arm saw, at 0 degrees. ____________

At 60 degrees on my table saw gauge. That gets me a boards with 60 degree pointy ends measured from the board edge. Haven't cut anything except straight cuts on the RAS for a decade or more. ___________

True for RAS, not the table saw. _____________

Cut one piece on a table saw? :) _____________

My main problem is that I should have stayed out of this thread in the first place :)

I'm sick of miters and intend to spend my few remaining years promoting KISBI (keep it simple, butt it). :)

[Doug Miller]

What table saw miter gauge is *that*??

Every table saw miter gauge I have ever seen reads *zero* for a perpendicular crosscut. What do you have, that reads 90?

Again: what gauge are you using???

It wouldn't get you that on my Incra 3000. Nor on the Incra 1000 that it replaced. Nor on the stock miter gauges that came with my current table saw, or either of my two previous table saws, or my currrent band saw, or the previous band saw. Nor on any other table saw miter gauge that I have ever seen.

Maybe not true for *your* table saw, but it's certainly true for the vast majority of table saw miter gauges -- representative example here:

_____________>>>>> In any event, it should be clear that if the device reads 44.5 for

Well, I think I'm understanding the source of your confusion a little better now: you evidently have a very unusual miter gauge on your TS.

[dadiOH]

The one that came with this Grizzly saw several years ago when it was right tilt and tube rails.