I am looking for some advice on building mitered doors and frames. I've worked for a big furniture manufacturer for years, and we mitered stock on a Bell 424A which bored for dowels at the same time. Then we assembled the frames on a Lancaster air clamp. A little glue, some senclamps for good measure and off they went.
Now, I'm trying to build the better mousetrap in my own shop. I can miter ok with my miter saw and a little sanding. I've read plenty of posts on that. My problem is assembling the frames. I have a couple band clamps but they don’t work well.
Does anyone have any ideas on an economical solution that gives a quality result? I usually work with oak, pine, poplar, and mahogany, and the widest mouldings I've fooled with have been about 3", and frame sizes from 6 X 6 up to around 24 X 36. I’m not looking for high production - just a way to build and set the frames off for the glue to dry. I have even used biscuits on a few larger frames, but still had a problem keeping everything clamped tight.
I do have an old Senclamp gun, but it just doesn't do its job unless I have solid pressure on the joint. And on pine, it's just fairly useless - the nails just crush the softwoods. I hope the pros take it easy on me. I thought I had all the answers until I realized my equipment doesn't compare to the multi-thousand dollar equipment I had experience on. But, like anything worth doing, there's a lot to learn and a lot to be gained.
(Furniture Making Forum)
From contributor P:
It is possible to glue up mitered frame with regular Jorgenson lightweight bar clamps, but there is a trick to it. Start by applying glue to joints and closing all four as well as possible by hand. Lay the frame on a flat surface. Put two clamps parallel to each other and tighten until the pads barely make contact with the wood. Rotate the clamp bars until they are flat against the frame. Then put two other clamps running 90 degrees to them, so that their bars are resting on the bars of the other clamps, and also tighten until they are barely closed.
At this point you have four clamps on the frame. The handles of both pairs of clamps should be on adjacent sides, the dead ends on the opposite adjacent sides. Now slowly tighten the two handles in on corner a turn, then the two handles that are not next to each other, back and forth, until the miters close. (This whole procedure is much harder to describe with words than to show you.) You have to watch carefully to make sure that the frames are in alignment as you tighten the joints - it is very difficult to adjust this while the clamps are tightening.
But if you positioned the frames correctly before tightening, the whole thing will close up very nicely. Also, you have to cut perfect 45 degree miters also. I have done this many times making picture frames for my wife, and it is quite fast and works well if you are careful. I use biscuits of splines when I am doing this. You might want to practice on scrap before doing this for keeps.
I would forget strap clamps – they don’t work well. You might also want to make a clamping frame two fences at 90 degrees, an open corner where the fences would meet, and an open bar back to support the glue ups - then you can clamp two sides of the frame to the fences, and it should square the frame and close the joints. With miters, perfect 45s and stock of consistent flatness and width make everything a lot easier.
Gross Stabil Mitre Clamps