Make certain that the router bit rotation cuts into the grain and not prying the fibers apart. Make shallow cuts several passes. If bearing guided bit, change to larger bearing and then to smaller bearings for subsequent passes until you reach the desired diameter. Sanding is safer. I tend to prefer round over bits over bull nose bits. The end result is the same, but the bull nose requires exact board thickness to get proper results. Doing one edge at a time with a round over bit doesn't require the board thickness, but does require using a router table and fence, at least on the second pass, and a zero clearance insert closely fitted around the bit profile, because the bearing will not have wood to follow during the second pass. If you try it, you will get a deeper cut and a step in the edge because of this. The bearing will want to ride on material that was cut away during the first pass.

Charley

 

Make certain that the router bit rotation cuts into the grain and not prying the fibers apart. Make shallow cuts several passes. If bearing guided bit, change to larger bearing and then to smaller bearings for subsequent passes until you reach the desired diameter. Sanding is safer. I tend to prefer round over bits over bull nose bits. The end result is the same, but the bull nose requires exact board thickness to get proper results. Doing one edge at a time with a round over bit doesn't require the board thickness, but does require using a router table and fence, at least on the second pass, and a zero clearance insert closely fitted around the bit profile, because the bearing will not have wood to follow during the second pass. If you try it, you will get a deeper cut and a step in the edge because of this. The bearing will want to ride on material that was cut away during the first pass.

Charley

Great information Charley. Funny thing is I have the bullnose bit so I didn't even think of using the round over. I am new to routing so sometimes I'm not seeing the full picture! I'm not sure what you mean by zero tolerance insert. Are you suggesting I make a ZT fence or are you taking about the table insert?

 

Welcome to the forum.

 

You definitely need to be doing this on a table (like all edging should be done) and be sure that you are using a feather board mounted on the fence to keep the wood tight to the table. Do the ends first then the sides. That way any splinters will be taken away when you cut the sides.

 

It's just a case of using the correct size bullnose bit set to the exact height and as stated, using a router table. These bits are available in many sizes.

 

As Tom mentioned doing the round corners won't leave enough to guide the bearing on the second pass. Possibility, leave a flat area between two round-overs...

 

Some months ago I posted this diagram of how I cut bullnoses - 2 passes using an oversized round-over bit

 

Of course the above is not a full bullnose, but a shallow bullnose can be very effective,

 

A zero clearance insert is just a piece inserted in the center of your router fence that a hole of the exact size and shape of the router bit is cut into. This leaves no voids around the bit for anything to get into. As you are taking the corners, it's easy to have your curved corner of your work dive into a hole alongside the bit. The zero clearance insert will work the same as one on your table saw that closes the gap around the teeth/cutter so nothing can go into it. This will produce a sharper and cleaner cut because it will hold the wood fibers from splintering as the bit shears off the excess.

Tengees , who is this Tom you refer to? As best as I can tell, there is no "Tom" in this post, at least not yet.

Charley

 

Got it! I thought that's what you were suggesting. I think that is a good plan. Lots of good ideas here!

 

Amana makes a bearing just for this. You take your first pass with a traditional bearing guided round over bit. After that you unplug the router and while leaving your bit at the same height change out the bearing with their radi bearing.

They have them in a few different sized but for example the 3/4" bit would be 57192 and that the replacement bearing is 47768

I stumbled on it a short while back and thought of it while reading this article, hope it helps.

 

I free hand my radius with a bullnose bit. 1 1/2". I go backwards a little at a time.

 

Welcome to the forum @pitttrack