Finger/box joints: a report

[foggytown]

Dear Group,

After all my playing around I can happily report that a router table with straight bit does a VERY good job making these kinds of joints. The fingers and spaces are uniform in size, fit snugly and look just fine. The set-up isn't difficult and the only problem was finally realizing that, unless a stop is used, the stock tends to kick right a bit at first bite and my holes were ending up a bit bigger than I wanted. I can also report that this mewthod works a lot better when the grain is perpendicular to the bit. (At least with the oak and utili I am using.) When cutting through cross grain the tearout at the back (even with a backer) is a problem.

Respectfully submitted to the Group, FoggyTown

[Leon]

May I add that it always a stronger joint when the fingers run in the same direction as the grain. If your grain is perpendicular to the bit you fingers will much more easily break off.

[foggytown]

Excellent point. I was probably aware of that somewhere in my deep subconscious but I'll think about it actively from now on. :)

FoggyTown

[Oleg Lego]

The foggytown entity posted thusly:

Use a backer/push block to shove the work through.

[George]

"Backer" seems to appear twice here.

Suppose it's worth mentioning that box joints are rarely seen across the grain because it's strong and easy to glue the long grain entire.

Spiral bits and slower feed rates should help, however.

[Bugs]

A router will do the job, but a dado blade on a table saw makes much neater cuts. I do it both ways with a home made micro-adjustable stepping jig that allows me to adjust the tightness of the joint. Bugs