need to draw 30 degree arcs

I'm trying to cut wedges Attachment 75227
to make this wooden trivet. The original was cut with a couple of jigs on the bandsaw, but I thought I could cut them on CW. I traced the outline using arc tool in Designer 2.xxx and thought I had the proper angle, but when I assembled it, there was a gap of about 3/16", so my arcs are obviously not exactly 30 :(. The proper angle on the intersecting sides is 30 degrees (12 x 30 degrees = 360). I need to determine exactly 30 degree arcs, and I also need a way to size them for different diameter trivets. Thanks for your help! :)

Ron

Here is a quick try, not exact, 12" outer circle, 11" inner circle, draw 30 deg angle then a 60 deg on top in the same quarter of the circle and mirror all four sides.
make an arc across the top and connect arcs from the middle to the first circle. you will have to make these one at a time, cause you cannot mirror them.
this my take on your request.

See what you think of these. You can change the radii of the small end arcs. That was fun to draw. The trim tool was crucial to making this. (See the original pre-trimmed curves on the back of the board.)

Hew here is another brainstorm, I not sure where I'm getting these this afternoon
Copy one of sections in the top right quarter, post it to another new project use cutpath and puff to your needs.
If you have all you dimension correct they should fit, if not sanding should work too.

Right you are! They are all the same. I never thought of that. I was too busy trying to draw them all. Typical academic!! (You would need them all if you wanted the grain to go across.)

This looks good. Now, how can I resize it? You suggested changing the radius of the small arc, but what I'd like to do is change the length of the wedge without changing the angles of the arcs. Is that possible?

The puffing also looks interesting, but not sure how practical that would be if placing objects on top of the trivet.

Thanks,
Ron

Quote:

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Originally Posted by t-townwilson

This looks good. Now, how can I resize it? You suggested changing the radius of the small arc, but what I'd like to do is change the length of the wedge without changing the angles of the arcs. Is that possible?

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You can scale it but changing the shape would require redrawing it. It would require using a different radius circle to trim with. It would not be so hard if you want it smaller, but start again if you want it bigger.

Do you have 2d advanced tools? If not, draw a circle the size you want on the original pre-trimmed curves on the back of the board and post. It would be much simpler, as myshop said, if you only need one orientation.

Are these closer?

Just curious how you are making them in designer. If you're tracing the path, are you offsetting the bit to compensate for the bit diameter?