In what order should I sand and route my edges?

Question

I'm building a kitchen table from a planed slab and want to round the edges over using my router and a 1/8in round-over bit. I am curious if I should sand up (80grit - 320grit) first then do my edge routing or vice-versa.

My intuition tells me it makes sense to sand first, since if I route first then it's possible to ruin the round edge when I go to sand. However, I could also see wanting to route first, as the edge will be sharpest and more uniform before sanding..

What is the best path forward here or does this not matter much?

Answer 1

I usually take a hybrid approach. I sand the flat surface to 150, then route the profile. Last I finish sanding to my final grit, whatever that happens to be. You do need to be a bit careful not to ruin the profile.

If you are worried about burning from the router bit, take a very light second pass with the router to remove the burn marks. If the pass is light enough it should not burn the wood any further.

Answer 2

You have correctly identified the trade-offs. There isn't only one right way; it depends on which you value more.

If I were in your shoes, I would probably do the routing first, and then sand. Routing can sometimes leave burn marks on the work piece. Anticipating that, I'd probably go ahead and route first, knowing that I can sand to clean it up at the end. Since you are planning on doing a round over, sanding it won't noticeably impact the crispness of the edge.

If you were doing a chamfer instead, that might change my calculation a bit. Sanding at the end would leave a slight but noticeable softening of the chamfered edges. It would depend on how badly I wanted the chamfered edges to be sharp.