woodnthings

I have posted this info a few times here but I'd like some comments on it: The settings on the miter saw are different than the angles cut on a piece held against the back fence...except at 45 degrees where they are the same. The settings on the mitersaw must be subtracted from 90 (degrees) to obtain the actual included angle on the workpiece. Example a 22 1/2degree setting on the mitersaw produces a cut or angle on the workpiece of 67 1/2 degrees. This might be a source of confusion for folks just starting out. Same thing on the table saw, a miter gauge set to 30 degrees will result in a 60 degree cut angle on the piece. Same as the miter saw, 90 minus 30 = 60.
So "settings" do not equal "angles".
A little more info while I'm here. A circle contains 360 degrees , and a triangle always contains 180 degrees, whether it is acute,(right has a 90 degree corner), or equlateral. So the sum of the included angles in any triangle will be 180 degress. And finally a 3-4-5 triangle will have a 90 degree or square corner. Any multiple of these dimensions will result in a triangle with a square corner. Example: a triangle with sides of 9, 16 and 25 will also have a square corner or 90 degrees. Or 3 squared, 4 squared and 5 squared. This is useful in the field to determine if the site layout of a building is square or rectangular. I have used 3- 100' tape measures simultaneously to do this. I hope that this is useful. bill

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If you're not making dust, you're gathering it. After I reread my own posts, I agree with myself even more.

Gene Howe

Thanks Bill.

firehawkmph

Bill,
I think you are thinking too much. It's kind of looking at the glass of water and trying to figure out if it's half empty or half full. All depends on which way you look at it. On the miter saw, a 22 1/2 degree cut is 22 1/2 degrees, off the 90 degree setting in the middle. When doing trim work, that is the perspective I usually think in. I have never thought of the 22 1/2 cut being a 67 1/2 cut, although it is both. As long as one knows there basic geometry like you stated above, they should be able to figure it out. When I stick my protractor into a corner, I am thinking in a perfect world, it should be 90 degrees. If it is 89, then I know I am going to cut at half that, or 44.5. Again, my mind is thinking in terms of the miter saw because that is the way it is marked. Uh Oh, now I am thinking too much. Good food for thought though,
Mike Hawkins

woodnthings

Mike, you're a smart guy..... you can't think too much, your brain will not permit it. It will shut down. You will get a headache, perspire and need a case of wobbly pops to cure it! You know the guys who designed these mitersaws were thinking too much since to cut a 60 degree angle you subtract 60 from 90 to get 30...that doesn't make sense to me.. I'm just trying to make a simple angle on the workpiece...not start subtracting angles.. Try a more obsure angle like 14 1/2 degress...it hurts my brain. Where's my calculator Let's see 90 minus 14 1/2 is ...hmmm something ending in 6 but no ... 5 1/2...75 1/2 degrees? See where I'm going with this for a beginning woodworker? Not everyone will agree, that's why I posted the thread. bill

__________________
If you're not making dust, you're gathering it. After I reread my own posts, I agree with myself even more.

firehawkmph

Bill,
I understand exactly what you are saying. It does get very confusing. That's why I try not to think too much. Most of my miter saw cutting is based around cutting casing and base, crown, shoe mold, pretty typical stuff. Pretty typical in the fact that we normally think of these cuts the way the markings are laid out on a miter saw. I guess that's probably why the manufacturers do that. When I get into a weird project, that's when I start drawing pictures on a block of wood, scratching my head alot, sit down for a few minutes, etc. Brings to mind a story from about 15 years ago. I was building a large home for a doctor. It had a hip roof system that was pretty chopped up. I had a framing crew out there that normally did a pretty good job. So one day I stop by and they are trying to figure out the exact length for the longest (main one) hip rafter on the house. They kept coming up with the wrong answer. And it wasn't something you could leave it long and trim it in place. After about an hour of head scratching, cussing, and what have you, the young guy on the crew who they treated as basically a lumber shuffler, grabs his pencil and starts sketching a bunch of triangles on a piece of plywood. He figured it out in a few minutes. His math was based on the ratio of one triangle to another (small one to a large one). The triangle sizes where based on the sizes of certain sections of the roof. Turns out he was an architecture student at Kent State, one of the local colleges. The older guys on the crew quit harassing him as much after that. Oh well, I'm heading out to the shop to finish a cabinet end for the neighbor. Simple 90 degree cuts.
Regards,
Mike Hawkins

woodnthings

If it weren't for my buddy coming over this AM I never would have thought about this, He's a rough carpenter/framer. I tell him about our discussion settings vs angles. He pulls out his speed square and goes " No problem, This is the same as the miter saw." I go HUH?? He goes "YAH, I always think away from 90 since 90 is plumb/vertical." I go HUH? What are all these other nos on this thing for? He goes "These are the angles if you pivot it, on the corner, marked "pivot" it gives you angles or roof pitches etc.."
I go "Let me see that thing!" Of course I've used one before, but only to cut square ends, so I never paid any attention to the rest of the numbers. He says "Yah, you get a book with it and it tells you all about it." I go " Mine never came with a book!" "I'm still a dummy on this thing!"
AH HA! What I finally realized was this:
I come from a drafting/architectural/ cabinet maker, woodshop, background.
He comes from a rough carpenter/ framing background, but he's a great cabinet maker too.
So, it's the way I learned vs the way he learned.
I always worked with drafting triangles, 30 degrees and 45 degreees,and a protractor, so everything was always measured in terms of the included angle.
He worked with that "speed square" which measures away from 90 degrees, like a miter saw, and has the roof pitch values on it . A 7/12 roof pitch is the same as a 30 degree angle. So, it was second nature to him to cut angles on the miter saw.
So, back to my original reason for posting, and I do appreciate your comments Mikey, for those starting out with some of these tools to immediately grasp the concepts behind them might take some 'splainin Lucy. Regards back to you! bill

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__________________
If you're not making dust, you're gathering it. After I reread my own posts, I agree with myself even more.

Willie T

I'm still trying to understand how your brain can shut down if you.. you... yo... y................
............................
....................................
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.
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................. uh... th... thin... think......... Yeah, that's it. THink 2 much!

What was I saying?

woodnthings

Was that a "brain fart" I heard? We can't hear you. What's your angle? Give us your settings. We'll find you. Hang in there. We have GPS and a speed square now. bill

__________________
If you're not making dust, you're gathering it. After I reread my own posts, I agree with myself even more.

Willie T

HELP ! I'm over here hanging off the table at 361 degrees. And I can't figure out whether to add 90 or subtract 30 to get back up on the top.

Request vector, direct home.

woodnthings

Counter Clockwise is above? I can't remember... I'll go flush the toilet and watch the swirls! This post got all side tracked apparently. And I'm not helping either! Anymore "thoughtful" comments will be appreciated. I was just thinking..... Yahoo search :
Which way does the water swirl when you flush a toilet on the equator?

on the northern hemosphere, the water swirls clockwise. on the souther hemosphere, it swirls counter-clockwise. What about directly on the center line ?????

__________________
If you're not making dust, you're gathering it. After I reread my own posts, I agree with myself even more.

BudK

Bill ,

Miter's !

Troublesome joints .
I use the same tool as you + a block plane & angle gauge . Hand tools seem to work well on these elder homes .
Cutting trim .
Saves trips back to the saw .

BK

woodnthings

BK, This post was less about how to make precise joints than it was about the confusion which arises over the calculation of the angles either on the miter saw or on miter gauge and how to get the proper angle cut. I think your block plane and a "shooting board" is the answer for fine tuning the cuts after we get the angles figured out. Others have said "don't rely on the setting on the saws.....that it's just an gross indication".. and it could be off by 1/2 a degree or so. I really like my Incra miter gauge with the indexing pointer for angle settings. But, I'm basically "lazy" so I would like to just "Set it and Forget it" but it's never that easy. Thanks for your reply. bill

__________________
If you're not making dust, you're gathering it. After I reread my own posts, I agree with myself even more.

BudK

Gotcha ,
I had to reread your post a couple times before it sunk in to the skullmud I call a brain .
Doing reno/restore work , I try not to find out the actual measurement of the angle . I always get in trouble when I measure stuff . I use the bevel gauge and set the saw(s) with that .

Thank you sir .

pace

I have been trying to find a chart of miter & bevel angles for the Compound Miter saw, similiar to the charts made for the table saw I have several of these charts and they all differ). I am trying to build a bird house with a Japanese lantern design, consisting of curves and tapered angles. Going thru a lot of wood w/o success..

woodnthings

I'll search again. last one "page not available!" bill

__________________
If you're not making dust, you're gathering it. After I reread my own posts, I agree with myself even more.

pace

Bill Thanks for taking the time but that chart is limited to Crown Moulding, not multi sided miters... thanks .

woodnthings

Let's try this one:
http://clipmarks.com/clipmark/10BBAF...-09D82FDD6D67/
This one has a chart for different nos of sides to angle and bevel.. I find it most confusing, but it's all yours!....bill
FYI: this chart has too many charcters to copy and paste....12,300 or so...sorry

__________________
If you're not making dust, you're gathering it. After I reread my own posts, I agree with myself even more.

bigdaddy4

hi i'm new here i neen to know where to set my miter saw at for a 67.4 cut.

woodnthings

Your setting should be 22.5 degrees like the photo which will give you an angle on the workpiece of 67.5 degrees, close enough! bill

__________________
If you're not making dust, you're gathering it. After I reread my own posts, I agree with myself even more.

rrich

Bill,
I'm sure that you remember "Complementary Angle" from school. That is the subtract from 90° thing.

Think of it this way with your miter saw.

"I need a 62.5° cut. So I'm starting with a square cut (90°) and I need to cut off 22.5° to make my 62.5° cut."

Simple, Right?

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Use the right tool for the job.

Rich (Tilting right)
Huntington Beach, California
Remember that when we have the "BIG ONE" everything east of the Rockies falls into the ocean.