Hello All:
I'm a big fan of Harvey Ellis design furniture so all my work has at least a couple of arched cuts. My current project has 12. After botching several pieces of nice oak I have arrived at what I think is essentially a foolproof technique for cutting uniform arches. The set up seems a bit time consuming but I am confident that it is faster from start to finish and with MUCH better results than other methods I have tried.
Step 1: Lay out the arch on a piece of inexpensive hardwood that will be your template. Of course this involves some geometry but I'll leave that out of this post. Step 2: Use a 1 x 2 or 1 x 1 to make a bow. Run a wire from one end to the other and devise a way to tighten the string to get exactly the bow or curve you want. That is, tighten it to make it match the curve you laid out on your template. Step 3: Rough cut your template on the bandsaw. The rule I use is "don't remove the pencil line" and I find that this give me the most consistent results. Step 4: Align your bow with the pencil line curve and screw it in place at 3 points minimum. Depending on the length, more may be better. Step 5: Use a flush trim bit on your router table to clean up the bandsaw cut to match the bow. Remove the bow and you have a perfect template. Step 6: Use the template to scribe the curve on each work piece. Step 7: Rough cut each work piece on the bandsaw as in step 3. Step 8: Mount the template on a work piece with double sided tape or screw it in place. DO NOT scrimp on tape!!! Don't ask me how I know this :-( Step 9: Clean up the cut on router table as in step 5.
This technique was my own idea but it may be well known and old news to some of you. If you already knew about it please don't make fun of those of us who are still in the process of discovery.
Cheers,
Jim