Let's go back to the OP's post:
Can't quite wrap my brain on how to tackle this.
I could make a template on my TS with my Wixey and then use it on the miter.
The miter only has 1 degree increments.
Suggestions?
ALL my comments apply.
Tom
Mike, let's go back to the actual post:
The emphasis, of course, is mine, because he was just asking a question, not telling you how to think.
I'll stand by all comments I've made on this thread.
Tom
Then why didn't you quote that?
Methinks the lady doth protesteth too much. :-)
Come on, Leon. Stop trying to be cute. He sets his miter guage at 19.4 degrees. Jeez.
Tom
To everyone on this thread, here's a trigonometry lesson, and for something like this, it is really, really all you need to know.
Who here has ever built a set of stairs, or put up a roof? It's all about the RISE and the RUN, right? The RISE is the vertical distance between the tops of two steps, the RUN is the horizontal distance between the noses of the steps. Or for a shed roof, the RISE is the height of the peak above the low side of the span, and the RUN is the width of the span.
Well the RISE divided by the RUN is what's called the tangent of the angle.
We're starting with an angle that we want on the edge of a board: 70.6. A little thought tells us that to get that on a table saw we need to set our miter gauge at 90 degrees minus 70.6, or 19.4 degrees. That's the angle we need between the miter gauge bar and the face of the gauge. When we put a piece of wood against the miter gauge face and run it through, we'll leave an edge on the board that has an angle of 70.6 degrees with respect to the side that rested against the miter gauge.
Now, we all have PC's right? And they all have a little application called the Calculator. Or we have a hand calculator and if it's a scientific calculator it has a TAN button on it. If it doesn't, fire up your PC.
Start up Calculator, or use your scientific calculator, and type in 19.4, then hit the TAN button. What you'll see is the tangent of 19.4 degrees:
0.3521555 plus a whole bunch of other digits. Now here's the deal: if you think of that in inches, it's the RISE over a RUN of one inch. For each horizontal inch, the line rises about 11/32 inches or a little more. For ten inches of run, it rises 3.521555 inches or about 3 17/32 inches.Now take a piece of scrap plywood, about 24 inches by 24 inches, with one good straight side. At about the middle of the best side, strike a line across it with your most accurate square - and it should be an accurate one - using a sharp hard-lead pencil or a striking knife. Since we have a
24-inch piece of plywood, let's use most of it: measure up that line exactly 20 inches and strike a mark across it. That 20 inches is going to be our RUN.With me so far? Now to use the tangent: Multiply the RISE over one inch (0.3521555...) by the RUN (20 inches), and you get 7.0431118... inches. In fractional inches, that's damned close to seven inches plus a 32nd and a half, or 3/64ths. At my age, they might as well not put 64ths on scales any more, so I'd do a 32nd and a half, as best as I could judge it.
Measure that distance to the right from the perpendicular line and strike it on the good edge of the panel.
Finally, draw an angled line between that point and that 20-inch cross-mark you made on the vertical line.
There it is. A line that describes an angle of 70.6 degrees with respect to your good straight edge.
Finally the rubber hits the road: take your miter gauge and turn it over and lay it down on the panel. Swing the bar until it lies along that angled line as closely as your eye can gauge it. Tighten down the screw.
But wait, you might say, what if I'm a little off with my measurements - what angle would I get instead? Well, as the calculator tells us with a little keypunching, if you were to use 7 1/32 instead of 7 3/64 (a 64th short), you'd get 70.63 degrees; if you were to use 7 1/16 (a 64th long) you'd get 70.55 degrees, and in either case we're out no more than 1/64 inch over a board width of 20 inches. Unfortunately our OP didn't tell us how wide his board needed to be, but it's probably nowhere near this wide. At ten inches of width, it turns out, it'll be no more than a thousandth of an inch off.
So put the miter gauge in the table saw and make your cut. Then offer the piece up to see how good your fit is, like we do with every board we've ever cut in our lives. It's going to be perfect, or damned near to it.
And if it's not, what do we do? We reach into our aprons, don't we, and we pull out a block plane and correct the fit by whatever it takes to make the fit air-tight. A 64th of an inch is one and a half thousandths of an inch, remember.
A faster and easier way to do this is to use an accurate protractor, as I've recommended elsewhere in this thread. You'll eyeball the .6 degree on any protractor I've ever seen - even a machinist's protractor- you'll make your cut, and you'll correct the fit with a block plane if you have to. For a reasonably narrow board you'll be damned near perfect. But even then, taking the time to lay it out as I described will get get you closer than the protractor would for a wide board.
Of course, if your miter gauge bar fits loosely in the slot, or there's some spring or flex, no measurement no matter how accurate will give you the results you want. But you need to fix that problem anyway, not just for this one cut.
There it is. I hope this helps a bit. I don't have trig right at my fingertips any more either, even though I've used it a lot in my lifetime, and sometimes I have to bumble around a little to remember what I need to do to solve a problem, but this part of it - the tangent - the rise and the run - is easy to remember and really pays its way.
Hope this helps, Tom Dacon
And he ends up with a miter at 19.4 degrees. He needs 70.6 degrees. The cut needs to be more towards a rip rather than closer to a cross cut. DOH!
Well, then you didn't look at Swing's SU pic. It *is* closer to a rip than a cross cut.
Another way to explain is this: Your blade is 90 degrees relative to your fence, right? Now subtract 19.4 degrees. Whatcha got now?
i know, I know, LOL
Another way to explain is this: Your blade is 90 degrees relative to your fence, right? Now subtract 19.4 degrees. Whatcha got now?
That would work if the miter gauge indicated 90 degrees but mine only goes to 50 degrees so... What are you going to subtract 19.4 degrees from on your miter gauge fence?
0 degrees or 45~ 50 degrees?The problem here is that the typical miter gauge has no 90 degree setting. What you think is a 90 degree setting is actually a 0 degree setting.
Any setting on the average miter gauge is going to result in a cut that is wrong unless you add a jig or template to hold the work's long edge 90 degrees to the miter fence and then set the gauge to 19.4 degrees.
Figure out the thickness of the block you have to put at one end of the fence to get .4 degrees, and put one there.
Well ya cornfused me on that one, Bubba. I'm pretty sure the blade is 0 degrees relative to the fence, at least that's the way it appears on MY table saw.
I think he is talking about the miter gauge fence.
That's not a FENCE. THIS is a fence:
or,, :~)
Everything that "you need to know" was posted with Leon's one line post, and my graphic representation of that one line that immediately proceeded it.
Simple, elegant, and with no need for an epic saga.
As Mike says, you doth protest too much ... if you're not a government worker, you missed your calling in life.
"Typically " an explanation like this is not one of repeated practiced experience, more so a repeat of something published. Those that have done this time and again realize that it is not a complicated feat and that knowing how to place the material on the machine accomplishs correct results in "much" less time than it takes to explain.
Balderdash, hogwash, nonsense......waitasec...oh...okay.
Balderdash, hogwash, nonsense......waitasec...oh...okay.
Is that a definite maybe?
I used to have trouble making up my mind, now I'm not so sure.
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