Melamine carcass construction

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Methods for the small shop. October 30, 2002

I've been building face frame cabinets with melamine interiors. I'd like to hear how cabinetmakers are building melamine carcasses. I have been using full length bottoms and tops with walls in between. I use a few biscuits for alignment and screw together with coarse drywall screws. While this gives good results, it doesn't seem like the most efficient method. I've been reading about confirmats in the posts but haven't tried them. Do they hold that much better than drywall screws? How are the parts held in alignment while they are inserted? Any other methods being used? I don't have the equipment for dowels.

Forum Responses
From contributor C:
Biscuit joinery is good, but parts need to be set longer than doweling for the biscuit to swell. If you don't have a construction doweler, this is a good way to go.

Upper and lower box ends run through (shelves in between) with a 1/4x1/4 dado 3/4" in from back edge for back panel with two 3 3/4 nailers added to back after assembly with pocket screws.

All parts are cut with melamine blades 1/8" oversize and run through a router table using a straight bit cutter that takes off 1/16" each pass for a chip-free edge for banding, etc.

Wood parts are stained and finished prior to assembly. Toe bases are attached to the cabinet underside during construction with cleats, and if you want a finish end that runs to the floor, a veneer can be applied and stained and finished after assembly. We also use hot melt glue around the back panel after squaring.

Screws work well and omit the glue-up time, but you will have to use veneer on finish ends. We use the screw system on laminated boxes.

We have been thinking about the possibilities of using the pocket screws for assembly with veneering on finish ends and bottom of uppers but don't know if the screws' diameter would be strong enough to withstand handling till the job is installed.

In reality, one should get a vertical/horizontal boring machine that does line and construction boring and use a box clamp to assemble and square the boxes.

The face frame joining machines we make can now be retrofitted to achieve a clean cut in melamine and cross grain veneers and hardwood. For the face framer not ready to invest in construction drills and case clamps, this provides a small shop alternative to the process that works well. Other manufacturer units have similar capability. The key is the quality of the cut in melamine. We're pleased to say we've crossed that river.

Jon Elvrum, forum technical advisor

Drywall screws? A woodworker should be using wood screws - they are not the same thing. On melamine I will always dado and glue and screw. Occasionally, if the end of the melamine will be seen, I will pocket hole instead of screwing from the outside.

From the original questioner:
I like the pocket screw idea and use them frequently. I have used them with the biscuits for carcasses. I've considered several ideas, like clamping a block inside the box to line up the corners, but these seem slow and inefficient. Any other ideas for keeping the corners aligned and flush while driving the pocket screws?

In a small one or two man operation, I remember a few years back seeing a corner clamp from Bessey that was fairly inexpensive and extremely effective. You can secure two panels at a corner and keep them square while the screw is being inserted. I liked them. Maybe someone else has another clamp to recommend or knows where to get the Bessey - I see Bessey clamps sold through a lot of our machine and hardware distributors. Check with your larger hardware supplier or a larger machinery dealer in your area. You might also try Hafele.

Jon Elvrum, forum technical advisor

When I need to align something for screws I frequently grab my staple gun and pop a pair of 1 1/4" staples into it. If you're screwing it you must already be covering the screw heads so a couple of staples won't be an issue.

I agree - get rid of the drywall screws and get particleboard screws. The kind with the cutting ridges under the head so you don't need your countersink bit are awesome. I did use Quickscrews, but my supplier changed brands and I can't recall what these are now. Also, square drive screws work much better - they stay straight on the driver bit.

From contributor C:
There is another way of joining frameless cabinets and I will try to explain. Let's just call it a "dovetail dado".

You would have two dedicated routers set up on a router table. One for the single pass dovetail dado on the inside end pane that stops 3/8" from the front (stop dado) and the other for the two passes for each side of the shelf which make the tongue. You would need to make this cut (the tongue) a little smaller to allow for glue in the joint and easier assembly. After the parts are milled, you would glue your dovetail dado and slide the shelf in, assemble the back - cleats, etc. - square the box and hot melt the edge of the box and back. The key is to make the match just right and be careful of humidity that could make the exposed parts (especially the tongue) swell and be difficult to assemble. Actually, the box should be assembled as soon as it is milled and if spraying finish parts, first the tongue and dado should be closed or protected so there will not be buildup of finishes or any way that the parts would swell.

Of course, the construction boring and dowels are by far the best, but there are lots of ways to assemble frameless boxes and what works for one will not for others.

We been assembling face frame cabinets with melamine interiors (approx 8000 lin ft a week at current rate) for over 15 years (10 years before that with Kortron and Decragard?) by screwing frames together and simply nailing carcasses together and attaching frames to them with 1 3/4 finish nails. Nothing has fallen off the wall or fallen apart on the jobsite or on delivery or in a container to another country and we do not expect anything to fall off the wall or apart in the next 25 years.

Biscuits, dowels, confirmats for face frame cabinet carcasses? That is a complete waste of profits and adds no significant strength to the cabinet - it isn't going anywhere.

Face frame cabinets hang by the nailer strip, which is placed under the top - every part of the carcass captured on at least two if not three of its planes by nails or staples, using the sheer strength of the nails (you remember, like houses used to be built in better times). More than enough strength here in earthquake CA. Glue the frames on a squared case, sand, detail and hang the doors and drawers and deliver the friggin' thing and get paid.

Cut parts that are the right size, assemble them in an orderly, common sense fashion and move on.

The clamp that Jon mentions was the Bessey WS-3. It is/was a corner clamp that absolutely provided a 90 corner but provided no pressure on the joint. That is, the 'clamp' is a positioning tool, not a clamping tool. If I recall correctly, one was at the front and one at the back of a cabinet joint when demonstrated by one 32MM system instructor who then bored for a confirmat with a hand drill. I believe the WS-3 is still available at tool stores and cabinet supply distributors.

From contributor C:
You're right - there is nothing spectacular about face frame cabinets. A few dados, some glue and nails (forget the screws), a square frame and back panel and you're set to go. On the other hand, if you're building frameless cabinets (carcass), there are a multitude of variations.

Costs to produce frameless systems are less to build and by utilizing the 32mm system, holes can be a breeze. Lumber used in the making of the frame can be utilized in the doors, which is one less step in constructing, assembling and finishing.

The comments below were added after this Forum discussion was archived as a Knowledge Base article (add your comment).

Comment from contributor B:
One of the contributors denounces drywall screws in favor of wood screws. There is nothing wrong with drywall screws if the holes are properly drilled, but it is difficult to get them perfectly flush, even if the hole is bevelled. This is because they are actually "bugle heads" as opposed to bevelled. Also, the holding power of wood screws has long been discredited because of the tapered threads, especially in MDF. Best, in my opinion, is sheet metal screws, with a true bevelled head. They have greatest strength and best holding power.