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Hello, all! I'm new to the world of woodworking: did some shop class stuff and Boy Scouts, but otherwise, not much.

My friend and I have been working on putting together a coffin for Halloween. To do this, we've found that getting the miters of the side planks to meet up is really tricky: the angles are extreme (12 deg., 56 deg., etc).

Of course, the table saw will slant, but only to 45. For some cuts, we can simply use the complimentary angle and run it through the other side. On others, though, no solution is obvious. We ended up building up a second piece of wood to raise the angle of the wood being ripped (dangerous).

So, what's the right way to do this? How do you cut extreme angles on large boards?

Thanks!
 

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where's my table saw?
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angles, miters and bevels

The angle of a miter or bevel is a number...12 degrees, 56 degrees.
A miter is essentially a crosscut, usually at a 45 degree angle. but not necessarily.
A bevel is a continuous cut like a rip, generally using the fence on the away side of the bevel as a guide. Any bevel greater than 45 degrees must be made with the workpiece showface up on the table and will be the compliment of the saw setting. 90 - 56= 34 degrees. Depending on the length of the bevel you can use the fence or the miter gauge.
I wouldn't add separate pieces to build up heights to make the bevels, :no: as you said it's potentially dangerous. ;) bill
 
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So we should hold the plywood vertically to feed it through? Isn't that dangerous too?

You are using some vocabulary with which I am unfamiliar (workpiece showface).

Let's use th 12 deg as an example. The only way I can see to get a 12 degree slant on a plank of plywood is to feed it through vertically with the saw slanted to 78 deg, right?
 

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12 degreees is extreme!

and you are correct it would have to be held vertically. Depending on the desired exposed length, an ordinary 10" table saw may not have a great enough depth of cut. According to my calculations and a trail run in the shop, the depth of cut necessary to bevel a 3/4" thick piece at 12 degrees is 3 3/4". A 12" table saw would be necessary. I used a miter gauge set to 12 degrees and made a cut so the base of the triangle is 3/4" wide and the tip is zero. The hypotenuse is 3 3/4"
Then the issue is the supporting the workpiece on a knife edge. It may tend to work down into the throat plate unless a zero clearance plate is used. There are several issues with this operation/procedure... namely capacity, safety.

No solution comes to my mind immediately, maybe someone else?

The show face is the good side of the work, the one that "shows".
 

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Let's use th 12 deg as an example. The only way I can see to get a 12 degree slant on a plank of plywood is to feed it through vertically with the saw slanted to 78 deg, right?



On the table saw, with the workpiece flat to the table and the blade is straight up (90 degrees to the edge), when you start beveling the blade (cranking in an angle), @90 degrees, it's basically set at zero.
When you get it over a bit more, you can set it at 12 degrees. When you crank it all the way it will be at least 45 degrees or more.


Maybe I misunderstand you.








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What cabinet man says is correct and basically simple.

I think the original poster and Woodnthings have overcomplicated the problem.

Can the original poster provide a sketch of what he wants?

George
 

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If you set the blade to 12 degrees and make a pass none of the angles on the work piece will be at 12 degrees.
For an angle of 12 degrees on the work piece, the only way I can think of is to hold the workpiece vertically and that's what I proposed.
For example:
Blade set to 12 degrees, work piece horizontal
, gives an acute angle of 78 degrees and an obtuse angle of 102 degrees on the workpiece.
That's not what I understood the question to be....I could be wrong...again.:eek: bill
 

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Blade set to 12 degrees, work piece horizontal
, gives an acute angle of 78 degrees and an obtuse angle of 102 degrees on the workpiece.
.:eek: bill
You don't get 12 degrees, you get 90 degrees minus 12 degrees, or 78 degrees on the workpiece. It's always saw setting, minus 90 degrees if you use a protractor and measure the angle on the workpiece. Yes the blade is angled at 12 degrees but that's not the resultant angle on the workpiece. you think? :blink: bill

BTW 45 degrees is the only case where both the angles will be the same.... saw setting and workpiece.

The miter gauge works the same way:
 

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You don't get 12 degrees, you get 90 degrees minus 12 degrees, or 78 degrees on the workpiece. It's always saw setting, minus 90 degrees if you use a protractor and measure the angle on the workpiece. Yes the blade is angled at 12 degrees but that's not the resultant angle on the workpiece. you think? :blink: bill

BTW 45 degrees is the only case where both the angles will be the same.... saw setting and workpiece.

The miter gauge works the same way:
I may have misunderstood the OP, but I think he meant the 12 degrees was a bevel with the blade (the blade tilted over), not a cut with a miter gauge.








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no you weren't confused

I may have misunderstood the OP, but I think he meant the 12 degrees was a bevel with the blade (the blade tilted over), not a cut with a miter gauge.








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http://www.woodworkingtalk.com/f27/angles-setting-miter-saw-9644/

I used the miter gauge as an example of 90 degrees is zero.
The OP was referring to bevels, not miters so I may have confused you with the example of the miter gauge. But it requires the same approach to get a specific angle on the workpiece which will be different than the "setting" on the saw, blade tilt or miter gauge or miter saw. ;) bill
 

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I used the miter gauge as an example of 90 degrees is zero.
The OP was referring to bevels, not miters so I may have confused you with the example of the miter gauge. But it requires the same approach to get a specific angle on the workpiece which will be different than the "setting" on the saw, blade tilt or miter gauge or miter saw. ;) bill
Well, I don't agree with you. Saw settings are exactly that. Getting a specific angle, or bevel is cut with that setting...at least on all my saws. If you want to make it sound involved, you can say that some angles are "referenced" from an edge or from the fence. But in my lifetime if I set a miter gauge, or rotate a CMS, or tilt the blade to 45 degrees, or 22.5 degrees, that's what I get every time.








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You don't need to agree, but this photo speaks for itself. The setting is NOT the angle you get on the workpiece when read with a
protractor
You're making cutting angles too confusing. It's not. You haven't invented a breakthrough in geometry or the math to figuring angles. I wish you had, as then you would have TV shows, and books to sell, and they would likely name a cereal or a street after you.

All the saw manufacturers of table saws, RAS's, and miter saws, stamp, engrave, paint, or screen print the degrees on their saws for what angles to crank the wheel to, or rotate an arm to. Some even have indentured click stops in addition to the markings. None of the manufacturers are going to change that to what angle you will have left after the cut.

The saw setting tells you what you are cutting off (in relation to 90 degrees), your protractor thingie tells you what's left (the complimentary angle).








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you made my point in your last sentence

You're making cutting angles too confusing. It's not. You haven't invented a breakthrough in geometry or the math to figuring angles. I wish you had, as then you would have TV shows, and books to sell, and they would likely name a cereal or a street after you.

All the saw manufacturers of table saws, RAS's, and miter saws, stamp, engrave, paint, or screen print the degrees on their saws for what angles to crank the wheel to, or rotate an arm to. Some even have indentured click stops in addition to the markings. None of the manufacturers are going to change that to what angle you will have left after the cut.

The saw setting tells you what you are cutting off (in relation to 90 degrees), your protractor thingie tells you what's left (the complimentary angle).








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The saw setting tells you what you are cutting off (in relation to 90 degrees), your protractor thingie tells you what's left (the complimentary angle).

You made my point, we agree.

That's all I was getting at, you have to set for the complimentary angle to get the desired angle on the workpiece. It's not complicated, once you understand it, you just do the math.
The setting is used to cut off the waste, not for the final angle.

I never claimed to have made some breakthrough. And the remarks about cereal were snide and unnecessary. Why do you feel a need to insult someone with who you "disagree" especially when in fact you reached the very conclusion I was advocating?
:thumbdown: bill
 

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What's the OP's benefit of this bickering?

It's difficult to understand what exactly he's after and maybe he has misunderstood the terminology. So if you could post a picture or a drawing of what you want to accomplish it will be a lot easier to give a relevant advice.
 

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The saw setting tells you what you are cutting off (in relation to 90 degrees), your protractor thingie tells you what's left (the complimentary angle).

You made my point, we agree.
I agree that's what happens, but not that it's the method I use.

That's all I was getting at, you have to set for the complimentary angle to get the desired angle on the workpiece. It's not complicated, once you understand it, you just do the math.
The setting is used to cut off the waste, not for the final angle.
When I'm setting the saw for cutting the angle (0-45) I set the saw for the angle. I don't first do math to figure out what the complimentary angle would be. I would prefer to make explanations simple and unencumbered for the benefit of those that aren't experienced.

I never claimed to have made some breakthrough. And the remarks about cereal were snide and unnecessary. Why do you have feel a need to insult someone with who you "disagree" especially when in fact you reached the very conclusion I was advocating?
:thumbdown: bill
I didn't reach a conclusion from what you advocated, but rather addressed the significance of the saw settings. I'm sorry if you took what I said that way, as it wasn't meant to be insulting. Actually, if they named a cereal after me I'd be pretty happy.:yes:








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Yes, it's off track

What's the OP's benefit of this bickering?

It's difficult to understand what exactly he's after and maybe he has misunderstood the terminology. So if you could post a picture or a drawing of what you want to accomplish it will be a lot easier to give a relevant advice.
Agreed! :thumbsup:
I gave my suggestion in post 4 and I stand by that , based on the OP's own words..."hold the plywood vertically" blade set to 78 degreees from horizontal, 12 degrees from vertical, it doesn't matter which way you do it. The capacity of the saw, assuming 10" blade will not work, you need a 12" blade/saw. :yes: bill
 
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