How to do a bullnose with a roundover bit?

**LBrandt** · 06-09-2006, 06:56 PM

Hello,
If I want to put a bullnose or at least a partial bullnose (maybe with a small fillet on the top and bottom) along the edge of a five foot length of 1x6 oak, and if I want to do this using a roundover bit instead of a bullnose bit, can anyone tell me how to do this? If I use a roundover bit with a bearing to follow the edge, how can I avoid the problem that will occur when I have no “edge” for the bearing to follow, once I turn the piece upside down to roundover the other side?

I don’t think that I can do this with an actual bullnose bit. I have a router table but no router for it yet, and the old Craftsman router that I do have won’t fit the router table, so I will have to do this operation by hand. I realize that I’m a router newbie, but I don’t think that there’s any way to use a bullnose bit without a router table. If that’s correct, I’m stuck with trying to do it by using a roundover bit and rounding over both sides.

Any help will be appreciated.
Louis

**beamerweb** · 06-09-2006, 07:04 PM

Grab yourself a scrap of plywood or other sheet good and mount the router to it with a hole for the bit to stick through. Throw on a straight chunk of 2x4 for a fence and you've got a router table :)

If I were in your position, I would run the round over bit in a table with a fence to isolate the bearing (basically put the fence flush with the bearing). Then I'd run the piece "vertically" - the wide edge against the fence. Set the height of the bit to JUST a little less than flush so you don't take away your whole surface.

It depends on what thickness you're working with and the radius of the roundover. If the round over radius is more than half the thickness of the board, you're gonna have to be very careful about accuracy.

Then it's just a matter of running the piece through vertically, rotate and run the opposite face through. If your bit is too high, you'll end up "jointing" that edge - that is to say removing the material you're using as your bearing surface. If that's what you want to do, you'll need to shim the outfeed side of the table for the second pass. I don't advise this approach. Take less than full depth and you should be fine.

EDIT: Oh, for your filet, all the more reason to use a fence. Then you can just take the bearing off the bit and let the fence back to make a little step on the face of each pass.

**LBrandt** · 06-09-2006, 08:18 PM

Jason,
Thanks for the quick reply, but I'm sort of mixed up as to what you mean when you say "run the piece through vertically". I assume that the makeshift rounter table that you're describing would be configured like any other router table, that is, with the router mounted underneath and the bit coming up through the hole. When you say "run the piece through vertically", if I want the 3/4 inch wide edge of the board to have the bullnose, won't I have to lay the board flat on its side and run it through in the same way that I'd do it on a standard router table?
Louis

**beamerweb** · 06-09-2006, 10:31 PM

You're picturing things right. Flat panel with a hole, board on top as a fence, router dangling underneath. Conventionally, the board is run through on a face, like you mention.

You can also run it through on edge as long as you set the bit hight such that the roundover just sort of fades into the edge (no fillet). It might feel a little awkward for some. If so, I suggest a thicker fence. You might also toss together a featherboard to help keep you vertical.

There's nothing wrong with doing it vertically, really. It may feel better with the scrap 2x4 fence set vertically as well so that you have a good half of your board supported.

You could also do this whole thing lying down, too. I have just found it easier to route both sides of an edge vertically. I'm a bit weird, i guess. If you go with the horizontal way, you would still use the fence instead of the bit's bearing - that way you will have support all the way through your cut, no matter where the "remaining" part of your edge ends up.

The way I pictured it, you may be using a roundover bit whose radius is more than half the thickness of the board to give a true bullnose profile. By that, i mean the edge wouldn't come out in the shape of a half circle, but rather a small portion of a larger diameter circle. But then I noticed the want for a "fillet" on the surfaces. Going horizontal might work better for this, you'd just raise the bit instead of removing the bearing.

This just goes to show that there are always a number of ways to pull something off ... even just inside my own head! :D

**Cody Colston** · 06-10-2006, 01:24 AM

Louis,

I can't add anything to what Jason said but I would recommend you test on scrap before you run the actual piece through. Use scrap pieces of an identical thickness and you can adjust the bit/fence until you get it exactly right.

Cody

He is no fool who gives up what he cannot keep
for that which he cannot lose.

**Woody 1** · 06-10-2006, 06:46 AM

When you get that router in that router table you will be amazed how much better you will be , with so much less work. Everyones advise is on the money but I`m a little lazy. Woody 1

**woodchuck1954** · 06-10-2006, 12:24 PM

If I were you, I would get that router into your router table. Take the sub-base off and use it as a template, to drill the necessary screw holes. Leave the sub-base off when the router is in the table. If you need longer screws, your local hardware stores have so many, they sell them, standard or metric. All you need to do do is countersink them so the screw heads are below the table surface. NO BIG DEAL. Then you use the fence for the operation. I have done it many times, even made round dowels that way. If you cut half or more of the edge, you might need to add shims to the outfeed end of the fence. They can be on the outside of the fence, easy to calculate, after the first cut. If you cut less than half, on each cut, a little sanding will round whats left.

**arcticfox46** · 06-11-2006, 09:06 AM

Maybe I am missing something but I have bullnosed many pieces of wood in the past - especially stair fronts.

I have used 3/8 roundover bits on 3/4 thick wood. Done it hand held as well as in the table. No difference to me.

I roundover one side - then flip the board over and do the other side. I TINY little bit ov sanding. Looks great.

Real easy.