Machining for Lap Joints in 2x Stock
Ideas for rapid removal of material for lap joining 2x4 and 2x6 pieces. July 13, 2006
What are the various ways of quickly removing material to create lap joints? Material removal is 3/4" deep, 3 1/2" x 5 1/2, to create a 2x4 to 2x6 lap. We have used the radial with dado for about a year. Considered shaper, but a little wary. This is a product I have contracted in packages of hundreds. A savings of minutes would greatly add up man hours. The last job was around 30 hours for 1 man.
(Solid Wood Machining Forum)
From contributor B:
How large a blade will your band saw handle? You might try breaking it down to 2 operations - a crosscut on the radial arm and then finish it on a band saw.
From the original questioner:
Thanks. We tried it. When I timed the movement, it took longer. One man will be obligated for near 200 laps. Placing the pallet of components up within reach helped him a lot. These are pre-manufactured window surrounds (exterior trim kits with a projected sill side casing and head. The top is a lap joint. I will need to start another production in two weeks. It's 480 windows. A lot of pieces. I create an assembly line that then feeds them into the finishing room. We run the components to finish dimension through the molder, dress them clean. Weak time link is this lap. And no, I won't biscuit or face them together. The joint has never failed - I just want it to happen faster so this guy can pick up another part of the process. We could cut some massive knives for the shaper insert, but I hear a voice saying no. I have cut tenons on the shaper and this is much the same thing, but massive wood removal... Table saw with dado and a slide jig is another way. Any comments?
From contributor P:
Any chance of using the table saw in a two cut operation - with the grain, then across to remove, or vice versa, but do two or three at a time in some sort of jig?
From contributor W:
Perhaps a jig and a beefy handheld router? Something that you could slide a number of pieces into, with rails that could guide the router over top of the pieces, then just rout away. I have seen industrial tenon cutters that have large knives that remove both sides of the stock to leave a tenon in the middle. Maybe something like that, but one sided... That would be expensive for a new machine.
From contributor R:
I'm not real clear on how the dimensions of this joint are oriented, but I do think the shaper may be an answer if you are lapping ends. Otherwise, a CNC machine like a Shopbot may do it faster than a radial saw.
From contributor S:
Powermatic 2A single end tenoner, or any single end. They are made for cross cuts, and are fast and accurate. No longer made, they are at Ex-Factory among others. You can make the whole cut in one pass with new heads from C G Schmidt.
From contributor G:
Single end tenoner would be the best. You maybe could find an old surplus pallet notcher and modify it to work. Some table saws such as Northfield allow you to use up to a 4 inch wide dado head. This, with a sled or sliding table, would work. I guess it depends on how many you will need to do and if dedicated machinery is the right call.