Routing an arc molding

[Tommy Squires]

I have been asked to build an astragal molding to match one on a family heirloom. I found a bit that will work and can easily mill the straight pieces. Any suggestions on how to create the arcs on the ends? Two straight pieces are joined at the ends by arcs roughly 2 1/2" inside diameter to form an oval. What I am pictureing is a circle mounted on a sacrificial fence, eased into the bit and rotated. Once the molding is formed, it will have to be band sawed out of the block. Is there a better way?

[Tommy Squires]

No suggestions?

[Bill ThompsonNM]

That sounds like it might work if the molding itself is narrow enough --that's a small radius. Can you post a picture? Absolute control of the workpiece would sure be important with such a small piece.
Another thought, is it possible to cut what you need using a rosette cutter? They come in a lot of patterns. Or use a lathe?

[Andrew Joiner]

Does this help?

http://www.sawmillcreek.org/showthread.php?t=135467

[Peter Quinn]

Another thought, is it possible to cut what you need using a rosette cutter? They come in a lot of patterns. Or use a lathe?

Thats what I'm thinking, to have two sides that match perfectly. I'm thinking a square the thickness of your desired molding profile in your finished species, a piece of kraft paper, a substrate of your choice. Glue the three together as a sandwich, shape it with the rosette cutter, use a putty knife to pop your circle free. You can secure the work to the drill press fairly easily. I think I've actually seen a guy do that on the bridgeport at work. You can get rosette cutters ground to match a profile.

[Jamie Buxton]

I'm not completely clear on what you're trying to cut, but it sounds like you might consider a router equipped with a circle-cutting jig. The circle-cutting jig is just an arm attached to the router, and a pin attached to the workpiece. The arm has a hole in it so it pivots around the pin. You could fasten the stock to the bench, and use the circle jig to cut the astragal.

Astragal, in my limited knowledge, usually has symmetrical profiles across the center line. That is, you'd need to cut some sort of profile on the outside of this curve, and you'd need to cut the same profile on the inside of the curve. If, as you say in your original post, you bandsaw the inside curve, it has no profile. That's why I'm confused. You seem to have done only half the job. The circle-cutting jig I mentioned above could cut both the inside and outside profiles.

[Rob Hermann]

I saw this the other day. Will this help? http://www.eagleamerica.com/product/400-1297/best_sellers