Making curved corners

[Stealthwolf]

I'd like to make the frames below out of 2x1 timber and turn it into a storage rack. I reckon I can cut curves on the outside with a jigsaw. I plan to round over the edges with a trim router. How do I tackle the internal corners?

[dewaltdisney]

One way is with a straight router cutter with a bearing. You would have to cut a template that would allow the bearing to follow and cut each frame identically. The bearing follows the template which can be temporarily screwed on the frame top or bottom, or clamped, and the cutter works the stock. The stock removed will give narrower frame widths to allow for the inner curve. Making the template needs a bit of care and calculation to get right as any error will be replicated in every cut. Make a trial piece and see how you get on to understand the inner curve.

DWD

[big-all]

you will get an arc on the inside naturally because the bearing will act as if the corner was infilled with the same radius as the cutter bearing so may give the appearance you want anyway

any added material to the inner corners will have to be a perfect arc as the bearing will run on this and any deviations will transfer and may be magnified

[Stealthwolf]

Thanks. I've realised the best approach might be to use wider rails. If I get the outer curves perfect, then I can use a trim router and guide to remove the extra waste and hopefully match the outer corners.