Assembling Frameless Casework

Dowel, dado, or confirmat screw? August 9, 2005

I am looking for some advice about the best system of manufacturing frameless casework with the use of a nested based CNC router. Should I use a dado, or would doweling using separate boring glue and dowel inserter be an option? How about case clamps or bar clamps with pre-glued dowels? Any help is appreciated.

Forum Responses
(CNC Forum)
From contributor F:
I would suggest using a blind dado. There is no other machining required and the assembly is a breeze.

From the original questioner:
I've been blind dadoing for 16 years and these are the things I don’t like about it.

1. There is more material removal than any other method (more tool wear and machining time).
2. The use of yellow glue, staples, and finish nailers is required.
3. Unless others have a better idea, you have to lay up finished ends after assembly (which is very time consuming and messy).
4. You have to dip all of the horizontal parts.

5. Flush upper bottoms are tricky because you can't dado because you can see the joint from below (unless you use a blind tongue and groove joint which is time consuming).

From contributor W:
To the original questioner: What kind of cabinets you build now? Are they frame or frameless? How are you currently putting your boxes together? Wouldn’t you be laying up a finished end anyway? If you want the cabinet side to be your finished end, then you answered your own question because dowels are the only way to efficiently build that way.

From contributor J:
Confirmats with dowels is very good, and there is no need for a case clamp. Some people prefer using a case clamp and no confirmats though.

From contributor L:
We use confirmats, and they work well, but then you have all the finished ends to deal with. We are just in the process of setting up for dowels. I'm not sure at this point how the times will work. We are starting without a dowel inserter due to money constrains. Down the road I hope to get a Gannomat Index CNC drill and insert machine with the vertical drill unit. Does anyone have any advice on drill and insert machines?

From contributor M:
To the original questioner: What type of materials are you building with? Laminates, veneers, hardwoods? Are you building flush construction or slight reveals? (If you are using laminated materials, confirmats are great for unfinished.) To avoid lay-up after assembly on finished ends, take a look at Blum Flush Mount RTA fittings. They work very well as long as the assembly allows for you to hide them discretely. Use these in conjunction with dowels, and no clamps are needed.

From contributor C:
Miller Dowel offers a product that is a ribbed, hardwood dowel with a patented stepped-shoulder design which locks components together when seated. Miller Dowels are inserted from the outside; aligning and holding the components flush without clamps. They anchor in end grain, have instant set time, are non-corrosive, and are self-plugging. The ribbed design holds and disperses glue throughout the joint. There are many wood species available.

From contributor C:
We use dowel/confirmats. Fit and finish are great with the right machines. The finished ends are laid up in a full sheet, cut and machined without thru-bore and dowel/pocket mortised on. Dowel insertion is done manually at assembly, which is slow. My three man assembly crew is constantly ahead of my two man parts fab area, so speeding the assembly has not been the problem.

My PTP is running ten hours a day now (we just started routing our MDF doors as well). The confirmat really holds like no other method, especially in shipping and installation. It’s very reliable and customers recognize it as a high strength, quality fastening method. A lot are stapled or just hot-melted together anymore. We don't have to glue the dowels either, which makes field servicing a lot easier and a lot cleaner in the shop.