Dowel construction is an excellent choice for milling for cabinet assembly. A construction boring machine will give your production a uniformity that all other milling precedures lack. Uniformity is the key to adding quality and speed to any production system.
Gannomat manufactures the following dowel construction machines. link to individual machine pages.
All of the construction types above can be speeded up by adding sophisticated equipment. Question is, what improvement would there be in using expensive equipment when the final product would still have to be bench assembled.
Let’s eliminate the above construction techniques one by one for their obvious weaknesses.
1. Screws/staples- It would be hard and expensive to automate this process. The holding power of screws and/or staples is questionable especially in melamine board be it particle or MDF. Blowouts from screws and staples can shrink profits fast. Bench assembly is required.
2. Dado – If done with a sophisticated router it’s a wonderful “old time” construction method. But assembly requires skilled workers to assemble the parts without gaps showing and what do you assemble with, screws, staples? This is without a doubt the slowest method. It requires a number of bench workers to complete very many finished cabinets.
3. Confirmats- This does require a sophisticated machine with both horizontal and vertical drilling capacity and the screws themselves are expensive. Keeping alignment without dowels to register and align is is hard to do.
Confirmats were introduced by a hardware company back in the 1970’s. For some RTA applications they are OK but for productivity they can’t match dowel construction for the simple reason cabinets must be bench assembled.
Note: Using the above three methods screw ends or staples will show which means cabinets with finished ends have to go through another process.
4. Pocket screws – The biggest problem is aligning parts correctly. Like Confirmats, to register and align parts you may want to consider using dowels along with pocket screws. Bench assembly required here too.
Note: All of the above methods use bench assembly and squaring cabinets for unskilled assemblers can be a problem. It’s also easy to rack cabinets. Either of these problems will cause loss of time all the way through the final installation.
Which brings us to Dowel Construction.
Dowels have been part of woodworking and cabinetmaking forever, whether it’s chairs, cabinets or frames.. The reason is dowel construction is extremely strong. Dowels are also inexpensive and there is a lot of machinery available to insert and assemble with dowels.
Advantages of Dowel Construction- Once parts are machined dowel assembly forces the assembler to put the work piece together the correct way. There are no screw heads showing and no misaligned parts. To speed assembly a case clamp can be used.
Eliminating bench assembly and using a case clamp means while the glue is setting up, on the work piece in the clamp, the back can be installed on the squared work piece. The next cabinet can be preassembled and readied for when the preceding cabinet comes out of the clamp.Three to five minutes of clamp time is usually required for initial setup of glue depending on temperatures and the type of glue used.
So what’s the difference between bench assembly and case clamp dowel assembly.
Bench assembly requires a more skilled worker. A new worker can be easily trained in a couple of days and be proficient in a week.
With dowels complexity is reduced dramatically.
A worker using a case clamp is actually working on one and a half cabinets at a time. The work piece goes into clamp, the back is applied while the next cabinet is readied for the clamp.
Depending on material requirements there is no extra steps required for finished ends.
Uniformity and cabinet assembly quality are improved. Flaws are eliminated that crop up during bench assembly.
What does it take to setup a good dowel construction operation. It takes three machines to complete dowel boring successfully (assuming you have a saw that can cut squarely and an edgebander). 1. An accurate dowel boring machine. 2. A machine to insert the dowels into the parts. (Start with a pistol type automatic glue and dowel inserter). 3. A case clamp to clamp cabinets with enough clamping pressure to close all joints tightly and of course square the cabinet. My only suggestion is buy a new glue and dowel inserter with electronic and not pneumatic control.
There are many success stories of companies that use dowel construction techniques.
Finally, dowel construction is a uniform process. Ask any efficiency expert how important uniformity is to overall efficiency and I’m sure they will say it’s number one reason productivity increases with dowel construction.