A couple of days ago we attempted to glue up some box-type wood columns (square in cross section) using a 45-degree bevel joint at the corners. The columns are just over 4 inches square.
We ran each edge through the shaper using a 45-degree bevel cutter and power feeder, but gluing up was a nightmare. In the past we've had the best luck with the table saw and power feeder, but nothing's proved foolproof.
I've seen work by other shops with equipment comparable to mine and the joints are so tight it looks like the pieces grew together. As far as clamping, we've had the best luck using packing tape. But again, we need better quality. How do you do it?
Did you use a straight 45-degree cutter? I have had much better luck with a tongue-and-groove lock miter joint. With that the joint won't slip when you glue it up. If you machine it so both miters on one piece have the groove, the column glues up real easy.
Another solution, depending on your boring situation, is to use ready-to-assemble (RTA) fasteners (Hafele, Titus). If you can bore with accuracy both vertically and horizontally, you can use these. Then, only the last panel is tough to get in.
Crank the blade to 45 degrees and cut so you are taking only 1/64 inch off the edge. After making your cuts, lay your pieces on a flat bench, face up, and butt your miters together. Put a couple of small pieces of packing tape across the joint to hold it in place, then tape the full length of the joint.
Flip the piece(s) over and run a bead of glue into the bottom of the joint. Fold the column together, using the tape like a hinge. Then, open it back up. This helps the glue flow, making brushing unnecessary. Then close it back up and tape it to hold it in place.
This works really well. It's faster than the shaper and we've found that with MDF and particleboard, the shaper cutters get dull really quickly and don't make the quality of cut required.
I get perfect joints of this type by taking time for two things: I run my spokeshave down each face to make them SLIGHTLY concave. Then, I take time to make glue jigs which put clamp pressure at 90 degrees to the joint faces. Result: perfect miter joints.
Comment from contributor C:
When I made box columns I ripped each board at a 45 degree angle (one setup for all pieces), then put the angle down to the table and ripped a 3/8" kerf in the miter face on all pieces (second setup). Step 3: Rip splines to slightly less thickness of the sawblade kerf. I glued up two lengths at 90 degrees for each column, let dry, then put the two 90s together. Squaring was automatic and clamping was easy on final assembly. The miters couldn't creep with the spline holding it in place. I used 1 x 6 poplar to yield a 5 1/2" x 8' column. Caps and plinths were created using standard moldings mitered like picture frames at top and base.