I have used a 3/8” roundover bit with a bearing in a router table. I made an extra-large table surface (1/2” plywood) for more support of the drum. I kept the router bit slightly shallow and did the last bit of finessing the bearing edge with 220 sandpaper and a very light touch.

Josh

Tried it tonight with a 1/4 inch bit. I still got a bit of a ridge but was able to remove it with a light sanding, perfect roundover after that. Quite pleased with how it turned out.

My mid 60's Ludwigs have a 3/16" radius. I bought a Whiteside 3/16" radius bit at Woodcraft. I recut one edge on a shell I bought off of ebay and was amazed how smooth it was even with no sanding. It really proves that Ludwig's shaper bits were allowed to get very worn before they replaced or sharpened them.

https://www.woodcraft.com/products/whiteside-2100-beading-router-bit-1-4-sh-3-16-r-x-7-8-d-x-1-2-cl

Sounds like you did a great job! Can you post some pictures?

-Mark

So does that mean I should match the bit size to the shell thickness. Maybe that's why I still got a little bit of a ridge? Even though it was easily sanded away, I would prefer not to have to deal with it in the first place. I'm guessing that bit depth should be >= shell thickness to avoid getting ridges.

The ridge you experienced was a product of one of two things: the bit radius was less than half of the thickness of your workpiece (the thickness of the drum shell plus reinforcement ring) or your bit was a little too high in the router table so it took off more wood than you intended from the bearing edge instead of merely shaping the sides of the bearing edge. For me, I like to take off too little on the first pass, then adjust subsequent passes or sand the remaining ridge (unless there is too much ridge to deal with).

If the bit is greater than half the shell thickness, make sure the bit is not too high. Otherwise, you will keep removing too much wood and will have to keep removing the ridge each time you go from an inside pass to an outside pass. You’ll eventually shorten the drum!

Not easy to do on a 60's 3ply Luddy with the wrap installed when forming the shell; I found the workmanship of those shell very poor, it is a miracle they sounded so good.

You need to work that area by hand with sand paper, also do not forget to place shell on a flat table to reduce gaps.

It can be done but it is a bear. I usually cut a 1/2 strip of 220 sand paper and run it on the edges lightly, all around the shell, then check the gaps and fix the mismatch.