Sunday, March 6, 2011

a pretty good miter gluing jig

cherry, walnut and abalone mirror frames ....
what have we here? i'm going to go out onto a limb and say we have just come up with the definitive 'best' miter gluing and assembly jigs yet. i don't usually make statements like that, as i know there are untold methods to get the same results. but, that said, this one's pretty good. and, over the years, i have tried a lot of ways to skin that cat ... inherent in gluing four sided picture framelike objects is the 'clamping' problem and the 'moving' problem ... how do you keep all four corners of a frame lined up, the miters tight and the frame square? we've glued them up, it seems, using endless strategies and techniques, none of which, in the past, would i have said were easy and 100% successful ... suddenly, friday, an inspiration struck, as inspirations sometimes do, and now i feel we have solved a tricky problem once and for all ... click the photos to enlarge them ...
ok, the challenge ... to help scott with his show, (see the previous post), at the last minute, (thursday night) he needed two sort of large picture frames, (+/- 39 x 60 x 2), painted black ... will said he could do them and we were off.
in the past six months or so we have made at least a half dozen or more mitered frames with abalone details (scroll down), and we know that it can be a tedious and fussy task ... get those miters perfect on all four corners. yeah, right ...
so, i had this idea ...

* take a piece of square mdf 14" x 14" ... really check it for square. length parallel, width parallel, equal diagonals, etc ...
* set up your 3/4" dadoes and run a groove 3/8ths " deep, parallel to the edges, the width of your frame stock in from the edge ...
* make some 1 1/2" wide 1" thick pieces of something ... i used mdf cause it was hanging around
* notch (rabbet) the corners of those strips (for rigidity), get a nice fit and glue them into the dadoes, and fasten the corners ... see the drawing above and the photos below ...
* try as best you can to be accurate with these corners too as they will tell you about where to clamp your first piece of mitered frame stock. see below .
* add pieces the exact thickness of the frame stock rabbet around the verticals (these can be removable for future different frame stock, to allow the mitered pieces to sit flat on the jig ..
* cut the finished square into four pieces

to use it:

* cut your four mitered pieces and clamp up your first corner, eventually clamping all four corners and checking the diagonals of the frame for square when you're finished ...
* if you're good to go, unclamp and glue each corner in turn. when you're done, you should have a perfectly square, glued up, mitered frame.
works for us .... it'll probably work for you ...

10 comments:

Jeff Branch said...

Glad you posted this because I hate making picture frames. I have some beat-up only corner clamps, but your method is better.

Jason Herrick said...

Yes, Yes, Yes!!!!

Do you ever smack your self on the forehead and say "DUH!"

I just did. GREAT JIG! Thanks for sharing it with the rest of us.

larry said...

I am off to the workshop now to make one of these... could not have come at a more perfect time.. I have a new student who wants to make frames... this will be great.. thanks for posting.

Dai said...

Well done m8 makes life a lot easier, thats another jig to make on my to do list.

Dave

Ed said...

All this time and money spent on schools, classes & seminars to try and improve upon or craft. And all it really took was your arriving at that ahh ha moment to figure it out, Welldone.
I have always had a pet peeve about mitres due to the slipping and sliding. I have bought so many differtent gizmos to solve the problem and none work as well as this jig you have figured out.
I had made something along these lines while in my Cabinet Making/Fine Woodworking classes at college. But what I hade done was to shoot two pces of MDF to a substrate at 90 deg. and use that one confirmed 90 to clamp to.
The great thing I like about your idea is that you can move the jig to where it is needed instead of always moving the project to the jig.
My wife can't understand why I spend so many hours on the computer reading woodworking blogs and snooping around other woodworkers web sites.
The amount of knowledge I have gained over the years from browsing different sites and blogs is incredible. So much more than by reading a book or taking another class.
I have gained a huge amount of knowledge from following your site and blog. I thank you very much for being so willing to share your knowledge and craft with the rest of us. I guess I just love working with wood and am always looking for new ways of doing it. Old dogs can learn new tricks as long as we are still willing.

David (aka "Dave") said...

That's just fantastic. Thank you for sharing this with the rest of us. :)

pjae said...

Looks great. I'm not sure about the following step:"* notch (rabbet) the corners of those strips (for rigidity), get a nice fit and glue them into the dadoes" I'm assuming you cut a 1/4 " rabbet to allow the 1" stock to fir into the 3/4 " trenches.

Larky said...

Very nice jig thank you for sharing.

www.madrid-3d.com said...

Quite effective info, thanks so much for the post.

Eian said...

Well done! I will be making a couple of my own sets first thing in the morning!