How to use roundover bit on both sides and not get line in the middle

[Alan Lightstone]

I remember there was a trick to doing this, but I can't remember or find it.

I need to get a bullnose edge on a 3/4" cherry, curved top table. I've been using a 3/8" roundover bit with bearing on the top and bottom of the wood, but I get that line in the middle of the curve. I remember there was a trick for removing / preventing that, but I can't remember what it was. It was something more precise / repeatable than just sanding it.

Bullnose.jpg

Anyone?

Also, since this is a curved piece, is there a practical way of making this bullnose with a full bullnose bit? I'm thinking that without the bearing being able to limit the depth, there is no way to do it with that bit?

[scott spencer]

Put a shim on the outfeed side of the fence, use a featherboard, and you should be ok.

[Mort Stevens]

Sounds like you're doing it hand-held, a router table will prevent that kind of problem.

[Alan Lightstone]

This is the shape of half of the piece (mirror image on the other half). I don't think I can use a fence for this. My first run was with a starting pin without a fence.

[Jeff Bartley]

Alan,

I just encountered this issue myself while building a staircase whose first tread had a radius at one end. Usually for this I just use a fence on the router table with the fence set flush to the bearing on the bit. On the curved piece I used a split fence and set the fence so that the bit was set in a bit. Then the workpiece rested against both sides of the fence while routing. I readjusted the fence taking light passes till it made the full round-over.
I hope this explanation makes sense....it would take 30 seconds to show you in person!
Btw: this would also work with a full round-over bit.

[Jeff Bartley]

ok, ignore my previous post.......that technique would definitely not work with this pattern. A pin-router would work!

[glenn bradley]

I use double roundover bits but, haven't seen them in a 3/8" radius.

[Alan Lightstone]

Sounds like you're doing it hand-held, a router table will prevent that kind of problem.

No, definitely using a router table.

[Peter Quinn]

I know of no simple tricks to follow a pattern like that, but there is a tool that works. Its intended for solid surface which is much harder to sand, but works fine for wood.

http://www.amanatool.com/bits-fv/57190.html

Worth a look. It comes with two bearings, the first one is square edge, the second is beveled and slightly larger to ride on the radius created by the second. The only other option I could think of would be shaper with a pattern fixed to the work.

[Alan Lightstone]

Hmmm, Peter. That Amana bit is very interesting. I wish they had a slightly smaller size, but I think I can make this work.

Any other techniques that could work.

[johnny means]

I've done what your trying to do by wrapping the bearing with tape after the initial pass. It takes a little experimenting to get the right thickness but works well once set up. Also, your bearing needs to be in good shape, so it doesn't destroy the tape. Alternately, I've run tape along the routed edge in order to create the necessary space.

[Peter Quinn]

I wonder if you could borrow a bearing from a rabbit set or one of those bearing kits (mine happens to be Amana , infinity sells one, other probably do to) . maybe pick a fractional size up for the second pass? You may even be able to buy the tapered bearing from the Amana kit as a separate part and fit it to a smaller radius bit?

[Lee Schierer]

Just a thought. You need to make the pilot bearing slightly bigger in diameter to compensate for the curve of the first cut. You could try putting shrink tubing around your bearing and shrinking it down on the bearing. You might need two or three layers. Make the pieces slightly longer than the thickness of the bearing so the ends partially curl around the bearing. Shrink tube doesn't weigh much and since it will be all the way around the bearing it shouldn't cause any out of balance problems. Just make sure the shrink tube doesn't interfere with the bearing rotation. When you are done, you can remove the shrink tube without causing any damage to the bearing.

Lowes carries small packages in various diameters.

[Jay Jeffery]

I know someone who searched high and low to solve this problem. He finally found this bit and it worked great for him.

[Michael O'Sullivan]

Why not just sand off the little ridge? I doubt it would take much more than a minute.