Stupid math question of the day.

[Tom Veatch]

... I've never really understood why they use the angle of the blade to the surface of the fence as the reference and label it "0 degrees". ...

If you think of it as the "angle off square", then blade tilt and miter angle has the same definition. 0° is a square cut and 30° is "30° off square" for both miter and tilt. Don't know if that's why they're defined that way, but it seems to make sense to me.

[Rich Engelhardt]

Hello,
Thanks!

I *think* I have it.
I was using the formula Tim listed and was coming up with figures that didn't make sense to me.

So - to sum it up - if I set my blade @ 30* and rip each both edges of a piece of wood 3" wide - then cut off 6 pieces 5" long and put them together, I'll have a 5" high six sided box (w/out a top or bottom of course @ this point).

That makes sense - I guess- I'm still fuzzy about the "other angle", but I guess it'll sink in at some point.

I did make an 8 sided base once and recall I set the miters for 22.5* - so - 30* for six sides sounds reasonable enough to give it a try.

[Matt Ocel]

Rich -

post pics for us

[Jason Roehl]

I guess we could all think of it this way: a miter saw is a crosscut saw, so a perfect 90º cut would be 0º from normal, and the 60º cut the OP needed is 30º from a perfect crosscut, not the fence.

[Rich Engelhardt]

Hello,
Doh!

After turning this over in my head for a few days, a light suddenly went off and I see it clearly now.

Take a 12" pizza, cut it into 6 equal pieces, trim the crust off so the ends are straight - then I end up with a 12" six sided pie.

If I take it a step farther, and cut off 5" from each piece - starting at the pointy end measuring towrds the flat part left by the above cut off crust, I end up with a 10" six sided pie and a 12" six sided donut (or box).

The angle I want - 30* is what each side of the slice of pie & each side of the pieces of donut are.

Made perfect sence once I extened each side to a point in the middle.


Matt,
Wiill do.
The "box" is really a six sided bird feeder project my grandson is doing for cub scouts. I ran across a picture of one at a craft web site. It looks like it should be simple enough to make one similar to it.

[Myk Rian]

If you want a 60deg angle, cut at 30deg. When the parts are put together, you have 60.
I make 8 sided light houses, and use a 22.5deg bit in my router table to bevel the side pieces. 22.5 x 2 = 45.
To make the tapered sides, I use an angle jig.

[Thomas Williams]

Well, I am not sure about all the math formulas, so if I want to cut a multi sided project, I look at the quick reference angle chart on my Incra miter gauge. 6 sides would be 30 degrees. I also use to have a program for segmented turning that would give you the cut angle.

[Thomas Knighton]

It's funny how much discussion went into this "stupid" math question, isn't it?

I think it's safe to say it wasn't all that stupid to begin with.

Tom

[Mark Rios]

Hello,
Doh!

After turning this over in my head for a few days, a light suddenly went off and I see it clearly now.

Take a 12" pizza, cut it into 6 equal pieces, trim the crust off so the ends are straight - then I end up with a 12" six sided pie.

If I take it a step farther, and cut off 5" from each piece - starting at the pointy end measuring towrds the flat part left by the above cut off crust, I end up with a 10" six sided pie and a 12" six sided donut (or box).

The angle I want - 30* is what each side of the slice of pie & each side of the pieces of donut are.

Made perfect sence once I extened each side to a point in the middle.


Matt,
Wiill do.
The "box" is really a six sided bird feeder project my grandson is doing for cub scouts. I ran across a picture of one at a craft web site. It looks like it should be simple enough to make one similar to it.

Another example that pizza will save the day every time. It IS the perfect food.





(And doughnuts are the perfect dessert.)



Three cheers for math food.