Thread: Routing an interrupted circle?

That should work, provided things are set up so the section you cut away is never the part that should have had the OD against one of the fences...

Me, I'd be more likely to cut a 240mm semi-circle out of a suitable sheet and use that sheet as the fence. I'd also 'define' the start/stops of each tooth with saw cuts before using the router.

If I was mass producing more, I'd probably make an adjustable jig similar to a circle cutting jig for a bandsaw. Then you could use the one jig to make every cut on the piece. ie. round the piece to OD first, cut the teeth second, do a plunge cut and make the final cut for most of the ID. (Seperating the last bit by hand, just for safeties sake.)


Edit: by pure co-inkydink, I just spotted this recent thread and the first post shows almost exactly what I was talking about. Except the one I'm thinking of would have a stop on the sliding arm so you could slide it away from the cutter head, rotate the blank and return to same depth...

Well Skew I took your advice and made a 240 mm dia semi circle and used that for a guide. Worked great!
Saw cuts not so much...... With my 3 mm straight flute cutter it makes an almost perfect cut to the line but my crappy hand sawn cuts just leave a rough edge. But I did carve out the 240 dia semi circle to 260 dia to match the mating female 1/2. No saw cuts this time and it worked good and looks ok.

Cheers Phil