Carpentry and Woodworking - Round grooves with router

I restore canoes and need to make new seats...but I believe I have developed a "brain f--t" on how to make rounded grooves in a rectangle (square corner) seat. I know it can be done and it involves a pin.....can anyone shed some light on this??

Seems silly to ask but no questions asked are never answered.

I have always used straight/mitered corners but have recently seen the rounded corners and they are beautiful.

Thanks for any help,

Ric

Hi,
Am I following your description, that you have a rectangular seat in which you want to route out a series of concentric circles into the seat where the canoeist sits? If so you can use a circle jig, which I find hard to use for small diameter circles. Another way is to make up a set of templates from tempered hard board (masonite). You use a template guide in your router base about 1/8" larger than your router bit diameter. For a round bottom groove you would use a core box bit. If you are new to these ways, go to a library and get a book on router jigs, or router tricks,etc. Ask the librarian to help you find the shelves that have these books. Post back.
good luck,
Trent