How to extend a routed rabbet to the inside corners of a cabinet door or other frame?

Question

I fixed up a cabinet in my bathroom, and made a bunch of cabinet doors for it. One of the cabinet doors, I made to have a frosted glass insert with some towels behind it. I used a router with a rabbeting bit with a bearing to create the rabbet to hold the glass in the frame. However, since the bit is round, it was unable to get tight into the corners. I then used a chisel to finish off the corners.

However, the result of the corners was not anywhere as close to as good a cut as the routed section. When I look at the doors in my kitchen with glass windows, professionally made, the cut is perfect including the corners.

Is there a particular technique that is better for making the glass doors? Should I have routed the rabbets prior to gluing up the pieces? Or do I just need to get better at chiseling?

I'm not sure how I could have assembled it different, as I would still have corners prior to assembly:

Answer 1

If you can follow my additions to your drawing, I'm hoping it will explain. If you work it this way, you can make a lap joint, and you should be able to have the clean joint you are looking for:

Route to the end of the left board, then extend just the top portion of the right board to match the notch. This should give you the crisp corner you are looking for, plus it will give you a stronger joint as well. Use some small doweling if you you care to improve the strength even more.

Answer 2

I haven't tried either, but:

1) There are spring-loaded "corner chisels" which supposedly help in squaring these up

2) I've seen folks report using the square outer chisel from a mortising head as a homebrew version of that.

If you're doing it by hand, remember that the first step is to usethe chisel to "define your lines", possibly with a straight-edge to assist, then pare back to those lines; repeat until you reach desired depth.

Answer 3

Assuming 45° miters, I have seen the rabbet cut 2 ways, the first being the way you described. The second is the rabbet is cut prior to assembling. This way you can through cut, and not end up with a semicircular end/corner.

Next time, with careful measuring and planning, try cutting the rabbet before assembling.

If then pieces will be joined otherwise, a sharp chisel is most common, however there are also a number of square or right angle punches for such applications.

The corner can be scored with a straight edge and the waste removed with a chisel.

Answer 4

In my case we assembled the door using pocket holes for assembly. Then ran around the inside edge with a rabbet bit leaving us with rounded corners. I then used a chisel to cut small perpendicular notches on the rounded part and also chiseled the leading edge of the round on the perpendicular part of the corer (it is usually fairly small and one parallel chisel strike should clean it out. Finally I used the chisel with the bevel down (To control depth) to cut out these small slices and then finally a cleanup of the rabbet corner with some fine detail with the chisel. Repeat with the remaining three corners. This is effective for small project. For multiple copies such as picture frames you can make a big and use a small rabbet bit in the jig.

Answer 5

You can do it with a router IF you route each piece before assembly. Route the long edge with the preferred profile, then route the hidden ends with a bit that produces the reverse profile. These bits are called a cope and stick set.