Hi all,
I am building large mahogany frames for a client. The first is 36′ x 36′ to the inside of the rabbit. The wood is 4′ wide x 1″ thick.
I make picture frames on a regular basis, but not this wide. Should I be concerned about wood movement on 4″ wide mahogany? I was planning on using regular 45 degree mitre cuts. I have a dedicated frame chopper with blades.
On a regular frame, I use nails and glue. Should I use something more substantial on this? The frame will contain a print, mat, plexi, foamcore backing, and 1/4″ plywood backing, for ease of changing prints.
I was thinking of using buscuits, or pocket screws in the back, or both.
Also, does anyong have experience making perfect mitres on soething this wide? It is hard enough on a narrow picture frame.
Thanks for any comment,
Ray Fitzgerald
Replies
try using 1/4 in plywood splines and tite-bond;
I often make large mirror frames with wide material, I cut the miters on the table saw with a sled just for that, to reinforce the joint I put butterflies on the back, for 1" lumber I would use 3/8" thick butterflies, the joint will never come apart.
C.
Thanks for the idea, I have never tried a butterfly.Ray Fitzgerald
C, you wouldn't know of an online tutorial on making a butterfly, would you? I do have some walnut that would look really nice stained darker and used as the butterfly or a spline.Thanks,
Ray Fitzgerald
Ray,I don't think you need a tutorial, the procedure is quite simple:
Lay out your butterfly with a knife, use your router to roughly cut it to the desired depht and finish it with a chisel.
I cut the butterflies from a wide piece of thick wood (as thick as the widest part of the butterfly) on the table saw with the blade at the proper angle.
I finish the inside corners with a chisel and I slice them up to the desired thickness.
I don't know if this is clear enough: the side of the board becomes the face of the butterfly.
If you plan to make more than just a few you should make yourself (or buy) a jig to use with the router and a collet. in either cases you will have to work on the corners with a chisel.C.
36' or 36"?
4' or 4"?
Not to sound like I'm nitpicking, but there's a world of difference, and I actually have made frames close to the bigger sizes.
As someone else noted, splines or biscuits work well. I like to use through splines of a contrasting wood, and sometimes I'll cut biscuits into the back face across the joint and sand them flush. So far no phone calls.
The older I get, the better I was....
That darn shift key,,,,,yes, 36" x 36" and 4" wide,,,,,,,guess I didn't proof twice and post once.So you use a biscuit perpenicular to the face of the frame (on the back)Would you all cut the splines into the ends of each piece first, before mitreing? And how deep into the joint would the spline be?Thanks for any comment,
Ray Fitzgerald
Cut the mitres first. Then run them on the tablesaw at 45deg using a tenoning jig, a splining jig, or just running them by hand against the fence (I can hear everyone starting to tell me how irresponsible that sounds, but hey). 1/2" deep each side is plenty, no real rule there for how deep to go (how wide is your spline material on hand?) Reference all your cuts of the back face so that they flush up your piece. Then glue in the overlength spline material while you're doing the glueup. Trim up after everything has dried.
Alternately, yes I plunge the biscuit cutter into the rear face of the frame after I've glued it up. plunge for a #10 cut, then glue in a #20 so that it fills more of the cut. After they've dried, saw and plane them flush.
Sometimes I'll plunge the biscuit cutter into the edge/point of the mitre and glue a biscuit there. I made a little jig that holds the bisuit machine 45deg to the corner. Looks like a spline, but easier. Usually I do this for thicker stock or on small mitred boxes.
Best of luck.The older I get, the better I was....
Secure the miters with glue and finishing screws; putty or plug the little screw holes. This will keep the miters closed.
Too much movement will destroy the joint as when mitered pieces expand they open at the outside corners (because the wood expansion is almost all in the width) when green wood miters shrink they open up at the inside corners. I think you'll be okay on these though... mahogany is almost an ideal wood for what you are doing. Just try to protect the wood from excess moisture (seal it all around and keep it away from steamy environments). You may have trouble with your chopper as they seem best for small moldings. The mahogany is easy to cut though so try it before you go to plan b. I like to chop miters with the chopsaw... the secret is to make a rough chop about 1/16th inch long and then shave cut at high rpms (and with slow steady feed) to exact size. You can cut most anything that fits on the chop saw this way and get excellent miters. I used to make moldings and run a custom frame shop so I got lotsa practice. Most framing brads are a little short for these frames so some kinda biscuit, spline, or butterfly would be good to secure the inside of the miter corner. You'll be fine using your longest brads on the outside of the corners though. I sometimes drill a hole and gorilla glue a 3/16 inch oak or steel dowel into it as a sort of drillable spline. You can leave it blind on one side and then plug it on the other.
Miters for frames or anything else has always been my nemus but I have found that for frames with narrow stock the following works well. On the edges that will normally be the top side or the bottem and not easily viewed, pre drill, countersink and fasten with appropriate length sheetrock screws and plug with matched wood. The screws will pull the miters tight. a biscuit as has been mentioned for splines helps keep the alignment flush. There are also metal type butterflys with adjustable bolts to tighten up the miter joints from the back especially wide boards as you are using [they use them on preformed countertops to fasten the miters together. Good luck.
Thanks to all for your suggestions.
I ended up using biscuits, and a trim screw from the top and bottom. I would really like to use some of the other methods, but I have to practice them first, and I was running out of time.The mahogany was too wide for my chopper blades, so I used my Hitachi mitre saw. It is a very nice saw, but I have never had a mitre saw that cuts perfect angles. So, I would cut away from the cut line, put a 45 square on it, adjust, and cut again. Someone needs to make a mitre saw with micro adjustments. A small fraction of an angle makes a difference in 4" wide stock. I joined the top and two sides at perfect 90 deg. angles, then started cutting the bottom piece to fit in just right, sneaking up on it. Over cutting would have been a disaster, so I went slowly.
I also indulged in a Lie-Neilson low angle block plane to make very small adjustments. It is really nice. Also, when the mitres were joined, and there were slight differences in height along the mitre joint(to the touch), I could run the block plane right up the mitre and shave it flat. When finished it was perfectly square, with almosst perfect joints, which is a heck of a lot harder to do than people imagine. To fill any imperfection in the joint, I mixed sawdust and the stain into a paste and rubbed it in. That worked very well.I finished the frame with Red Sedonia stain, and 5 coats of wipe-on poly. The photo for the frame has a black background, which extends to all the edges, so I used a black acid free solid core mat, and non-reflective plexi for glazing. I installed a hanging cleat on the back and installed it last week. I was very happy with the results, and the client was ecstatic, he wants two more larger ones to go with it. I will post a picture of it when I can get back there with a camera.Again, thanks for all the suggestions, there are obviously a lot of knowledgable people here.Ray Fitzgerald
Big mitered frames, Been there, Done that. Did a large plate glass mirror. 3' X 4' (heavy) 31/2" X 1" S/R Ash. Solved the problem with a mitered Half-lap. Mirror has been hanging in the bathroom for 11 years now, NO problems
Work Safe, Count to 10 when your done for the day !!
Bruce S. Counter Sales, Tech Rep. http://WWW.EAGLEAMERICA.COM
I'm glad that it came out ok, but hand trimming a miter with a block plane can be a lot of trial and error work. If you're going to make a lot of these, you might try something that worked for me. I cut the 45 degree angles on the miter saw and then run them through the jointer. This gives you a very flat surface. It works well with softer woods, but really hard woods like wenge tend to splinter.
This forum post is now archived. Commenting has been disabled