miter corners for picture frame

[Gerry S. Wojtowicz]

Hi all,

I just finished a 45 degree angle shooting board last week and I've been experimenting with it.

I made two different sized picture frames, and when I tried to put them together, on both, one corner did not fit perfectly.

No matter what combination of pieces I used, one corner would not fit perfectly.

I checked the angle of all the pieces on both picture frames with a General digital protractor and all were dead on.

I assumed one piece was not the correct length and tried to measure them all and they all seemed to be the right length.

I can't figure this out. Any suggestions?

Gerry (geribo@sbcglobal.net)

[Bob Vavricka]

Gerry,
Check to make sure the opposite sides of your frames are the same length by standing them up with the long points together. If they are, then the problem has to be the angle. I suspect you are off a slight amount and you are seeing the cumulative error at the fourth corner. Clamp the frames together and check each corner with a square and also measure the diagonal distances, With the diagonal distances equal, I think you will be able to see where the error is and tweak your shooting board.

[Kevin Womer]

Gerry,
I watched a great video at wood.net, click podcasts, scroll down through several screens to podcast #4. Great tips there that you might find useful too. I built the table saw sled he recommends, out of basically just scraps and glue my frames with spring miter clamps. I get great looking joints, I cut them in the sequence it recommends which offers a little forgiveness-the reasoning is the principle of supplementary angles, if I recall correctly. I hope this helps, a long video, but I learned a lot of tips that can help your frames look as good as the frame shops make for ridiculous prices.
Regards,
Kevin

[Stan Calow]

I have sometimes found that one or more sides will have bowed or twisted enough to throw things off. The miter angles perfect but sides out of square.

[johnny means]

It doesn't take much error to cause this problem. If your shooting board is off by 1/8 of a degree you"ll be off an entire degree by the time you get to assembly. Factor in the tiniest bow and things are worse yet. Join the first three sides and than hand trim the last to fit.

[Michael Mayo]

I just made a picture frame miter sled for the tablesaw last weekend. It was the one that was in Fine Woodworking some time ago. It took some serious doing on my part to get it perfect but it came out pretty good and my very first test miter joint fit like a glove with no gaps at all. It uses metal straight edges from the Borg as the fences the Long fence has a ruler on it and a stop block that you use as he measuring point and it worked beautifully. I am going to try and make a complete frame this weekend.

[Bruce Wrenn]

Another option is to buy a Dubby from In-Line industries. After setting up, perfect cuts every time. I have one, and my only regret is not buying it sooner!

[Frank Martin]

Table saw with a good miter gauge always worked for me in the past without and hand tool adjustment. The key is straight and square stock, opposite sides are cut to the same exact dimension using stops, and miter gauge setup for exactly 45 degrees. I made many frames with no gap at the miter joints, ranging in size from 12x18 inches all the way up to 40x60 inches. I did all these with a Unisaw and Accu-miter miter gauge. I used lose tenon joints at the corners for strength. So, if you have the power tools, I say try using those for all the steps before resorting to a shooting board.

[Gerry S. Wojtowicz]

Hi,

Thanks for your comments. I have a sneaking suspicion that Stan might be correct. Some bowing. I'll check that out. As I said I measured the angles and lengths and all seemed to be good.Thanks again all

[Gerry S. Wojtowicz]

Hi all,

Just to update you on my 45 degree miter shooting board situation.

Apparently my shooting board was off by enough (although not much) to throw my 90 degree picture frame out whack.

Johnny Means was right.

I adjusted the shooting board and remeasured the angle with my General digital protractor and re sliced the four pieces with my Lee Valley low angle block plane. All four pieces fit perfectly. It's gluing up in the show even as we speak.

Thanks for your help.

90 degree shooting board up next.

[Gerry S. Wojtowicz]

Kevin

Thanks for suggesting the woodworking picture framing video. I watched it. Good stuff, especially the idea of complimentary angles. I'll be building that sled. If the angles don't come out exact, I'll have my shooting board to make them so.

[Kevin Womer]

Gerry,

Glad you liked it, the sled is worth your time, I just threw one together and my miters look very good as a result.

Good luck,
Kevin

[Jim Matthews]

I cheat, when making picture frames, and leave the last two pieces long.

With the first three miters assembled to square and clamped together, I overlap the
last two pieces to join and clamp them down with a holdfast.

I then saw straight through the last two.