[Skullcrafts]

How do I cut out wooden octagons?

I have a chop saw and table saw to work with.

I want each octagon side equal. I want the octagon cut out of a piece of 3 3/4"W x 3 3/4"H wood.

Do I cut the diagonal sides at 45 degrees or something else?

How do I map it out?

If I can get the octagon cut, can't I use that to make more? As in, using it for a template for later use.

Need help, please.

:drowning:

[rriveraz_mty]

you need to make 67.5 degrees cuts with the tablesaw in both sides of the wood when you assemble them you get an octagon.

[Skullcrafts]

you need to make 67.5 degrees cuts with the tablesaw in both sides of the wood when you assemble them you get an octagon.

I don't want to assemble them, I want a one piece octagon and then use that piece as a template for subsequent octagons. So do I set the saw at 67.5 anyway? I would assume that using a miter saw is better suited for cutting them out?

I have 3 3/4" squares to work with here, just trying to figure out how to make the squares into octagons.

[Skullcrafts]

Oh and just for an example of what I'm talking about, the following picture will illustrate what I'll be using them for. The octagon is not equal on all sides however. I want to get them that way...these were cut at 45 degrees (er...the diagonal cut). I have 4 sides equal and 4 sides that are too long.

[enri]

test

[HeritageAmps]

see if this page helps:
http://www.cleavebooks.co.uk/scol/calpolyg.htm

[enri]

see file

[enri]

I can draw the octagon smaller if you want

[NateTG]

On a 3.75 inch square, mark 1.1 inches from each corner and clip the corners to the marks. That will cut the original sides to 3.75-1.1-1.1=1.55 and the clipped corner sides will be of length 1.1*1.414...=1.555.. (If you really care, you could cut to 1.098 inches instead to get closer to equilateral, but wood usually can't hold that kind of precision.)

[Skullcrafts]

I guess maybe I'm not making myself clear enough, I apologize.

I don't need to know how to make an octagon. I need to know how to cut an octagon out of wood. What degree angle do I need, what dimensions, etc.

What is 1.1 inches? There is no "point" anything on any rule I have.

[NateTG]

I guess maybe I'm not making myself clear enough, I apologize.

I don't need to know how to make an octagon. I need to know how to cut an octagon out of wood. What degree angle do I need, what dimensions, etc.

What is 1.1 inches? There is no "point" anything on any rule I have.

1.1 is between 1 1/8 and 1 3/32 you'll probably be ok using either of those depending on your tolerances.

The side length of the octagon will be 1 9/16, so if you have a combination square (or other similar tool) that you can slide along the corner till a 45 degree line has that length, then mark and cut.

[ger21]

.1 = ~13/128"

[Skullcrafts]

Okay, I'll try that and see where I'm at. Thanks for the info.

[Andre' B]

You could try somthing like this.

The more perfect the starting square, 90° corners and the two dimensions the same the better. They should fit into the V in the fixture with no noticable movement.

[Riceburner98]

If you're still looking for ideas, I do this for 1-off simple parts I need to cut... Download the Emachineshop program (www.emachineshop.com) and install it. It's free, and it's a super-simple CAD program. Draw your block, draw the shape in the block, then print it 1:1 scale, and tape it to your part. Cut to the lines, and you're good. I'm guessing (or suggesting?) you'll need to make a small jig to hold the block that close to the blade to avoid lopping off a finger or two...

[beege]

Here's what I'd do:

Make sure your square piece is 3 3/4" on each side, and make sure its square.

Mark the center of the square by penciling diagonals from each corner

Use a compass to make a circle touching each of the four sides

Use a combination square to make a 45° lines touching the circle you sketched

Cut the corners to the lines.

Voila!

Do you think that would be precise enough for you?