Re: Skil Digital Angle Finder: huge mistake!

In article <Jtlfm.301073$jW1.21384@xxxxxxxxxxxxx>, "dadiOH" <dadiOH@xxxxxxxxxxx> wrote:
Doug Miller wrote:
In article <msjfm.168196$ay4.52749@xxxxxxxxxxxxx>, "dadiOH"
<dadiOH@xxxxxxxxxxx> wrote:
Doug Miller wrote:
In article <jAcfm.245563$TZ2.98717@xxxxxxxxxxxxx>, "dadiOH"
<dadiOH@xxxxxxxxxxx> wrote:
Doug Miller wrote:
In article <PS%em.190050$tU4.153039@xxxxxxxxxxxxx>, "dadiOH"
<dadiOH@xxxxxxxxxxx> wrote:


OK, suppose it did. Suppose you have a 150 degree corner and you
want to cut miters for it. The device tells you to set up a 75
degree cut. How do you propose setting that up?

That's easy: set the miter gauge at (90 - 75) = 15.

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

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. [*]

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.

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.

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

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?

___________

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.

Right

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.

Nope, both are correct.

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

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?

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

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?

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.

So where's the problem?

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.


_________

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.

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

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

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

That evidently was a long time in the past.

___________

[* 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. ..."]

Do you maintain that both of these readings are correct?

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.

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.
.

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