Face-frame joinery techniques
Cabinetmakers discuss various techniques for joining cabinet face frames. October 31, 2000
Is one method better than another for joining cabinet face frames? I'd like to hear your views on all the options, including glued mortise and tenon; biscuits; pocket screws; screwed butt joints; rabbet joints, etc.
Don't forget doweling.
I believe the choice depends on your casework construction method. All are acceptable types of joinery. With regards to the strength of the joint, it would seem to fall in this order, from strongest to weakest: mortise and tenon; rabbet; dowels; biscuits; and pocket screws.
We always found a slot mortiser to be the most effective way to make a tight, permanent joint in hard or soft wood in a semi-production environment. The joint-making is far more forgiving than most other methods, since it allows adjustment during assembly.
Though I believe the slot mortise and tenon joint to be stronger, the assembly process is more easily automated using dowels or pocket hole/screwed joints (especially the latter). This is likely an advantage in the high-production shop.
I've been using detail biscuits to join face frames for about four years now. No call-backs yet! This is the fastest assembly method I've found.
Pocket holes and screws work very well for us. It's very fast and quite strong. I would say the big problem with this system is someone who runs screws in too fast and strips the wood out. I use a cordless drill and tighten the joint carefully. No problems in 20 years (never a call-back). This system is probably the most cost-effective way to go for face frames, in regards to strength.
To improve on speed, and profit I think, you would have to go to frameless construction. Also, I use a Castle machine for the pocket holes. It comes in handy for other parts also.
I saw a shop that used corrugated-type fasteners shot through a special "nail gun." It appeared strong. I believe it was specifically for face frames.
Bostich makes a corrugated fastener air gun that shoots both 3/8 and 1/2 inch corrugated nails. It tends to split solid wood on the rail, but works great on plywood.
I find pocket-hole joinery the way to go. I have been using it for years now and use it not only for face frames, but for carcass construction in some applications. The biggest seller on pocket-hole joinery for me is that you don't need an arsenal of clamps. As mentioned above, no call-backs here.
I dowel mine on a Gannomat Superdrill. Butt joints and dowels are easy and, in my experience, strong. Just the other day when I screwed up a frame, I slammed it on the floor and the darn thing barely moved.
I prefer mortise and tenon, for strength. I let the customer decide. I tell them the costs and the pros and cons of each method. I have had great success with all these methods: mortise and tenon; biscuits; pocket screws; butt joints and screws; rabbet joints; dowels; and sliding tenons.
I use the Senclamps from Senco. The gun is around $500 and the Senclamps aren't cheap either, but they work well and assembly is fast. I attached a mini-regulator to mine and run around 40 to 60 psi. It is incredibly powerful. Louis and Co. has them.
I think the corrugated fasteners suck.
How strong does a face frame have to be? Once it's on the cabinet it's held there by the way you attach the frame to the box.
I use pocket screws and I don't glue the face frame together, but I do glue the frame to the box. Have never had a failure in thousands and thousands of cabinets.
I guess it would depend again on your case construction and what you classify as a failure.
Is a failure having a stile break free with a door still hanging from it or is a failure the cracking of your finish at the joint because of the door twisting on the stile each time you open and close it?
Even when I (used to) face-nail face frames to my 5/8-inch-thick partitions, I would put a little glue in the frame joint to prevent the joint from flexing and cracking the lacquer.
We dado the backside of our face frames and set the box (1/2-inch melamine) into the frame. We glue the face frame to the box using 3Mís JetWeld.
I'm not sure it's possible to keep the joints from moving between the rail and stile. We build our cabinet doors, use stick-and-cope on the stile and rail with glue at the joints. We still get minimal cracks at the joint. Itís only noticeable on white lacquer type doors and we try to use a one-piece door for that.
I'm curious to know whether you wide-belt sand your face frames prior to attaching them to your box. Do you prefinish your frames prior to attaching them to your box?
I know this is a popular method with prefabs, since they can blind-staple the frames on from behind. Also, what is the reasoning behind skipping the glue on your frame joints?
We run our face-frame stock through our moulder and are able to get very close tolerances. Then we just kiss the front and back sides with the widebelt. We also use the Castle machine for assembling the frames.
We do prefinish the frames prior to assembly, and the reason we don't glue the frames is that we've found it's just not necessary. When you glue the frame to the box with the 3M JetWeld, that frame does not move. It's a very good system, but we are not doing much in the way of face-frame cabinets any more; almost everything's Euro (much better).
The comments below were added after this Forum discussion was archived as a Knowledge Base article (add your comment).
Comment from contributor A:
For stronger and better looking face frames, we mortise the stile and tenon the rails, then glue and press them together. After that we send them to the planer sander (to remove offsets bet the rails and stiles) then to the CNC drill for final drilling. Squaring the whole assembly is done at the press (very critical when you do some drilling at the end).
Comment from contributor S:
Face frames are the vital aspect of all cabinets and strength is important. I've always used dowel joints and never enjoyed that part, but they're cheap and easy aside from the clamping time needed. Keeping glue out of the butt is important. Come finishing, there's nothing worse than seeing unstained wood. I'm going to try plate jointing, as it seems to me that speed and accuracy would be the benefit. I saw a lad take a plate jointed face frame and try to break it. It broke, but on the grain of the stile. I was impressed.