Dowel Construction: Fast, Accurate, Durable

Ryan Akhurst

The durability of the joint would be the primary consideration for case goods assembly. Speed of manufacturing and assembly is a close second. Finally, accuracy/tolerance are also essential to consider. There are several popular methods to assemble case goods in cabinet case good production, with the most popular being dowel, dado, butt joint, pocket screw, screw and nails, biscuits. When considering your preferred construction method, you need to factor in what is best for your operation. If using a CNC router, you can produce most of the popular joints. You should strongly investigate dowel construction if you are equally concerned with speed, accuracy, and durability.

Time to invest in the right tools

To take advantage of the speed of dowel construction, you need to invest in the right tools. Typically you will be cutting parts on a nested-based router or beam panel saw. After the pieces are cut and drilled vertically, you will take the fixed shelves and stretcher rails to a horizontal drilling machine or a drilling and dowel inserting machine. You then go to the assembly stage, ideally using a case clamp. Insert into the holes on the cables glue using an electronically controlled glue applicator or a fully automatic dowel drilling and inserting machine. Inserting the correct glue amount ensures a strong bond with no cleaning. Then into a case clamp for final assembly. Clamping time will depend on the glue, but it will typically remain in the clamp for 2 to 5 minutes or as quickly as you can assemble the next cabinet to insert.

The assembly is very fast in comparison to other construction methods. Also, as the dowels are hidden, there is no need to cover up nails or screws on exposed ends. If you are nesting the cabinets, a typical cycle time would be around 6 minutes per sheet with dowel construction and up to 10 minutes compared to blind dado. You do have the extra step of taking parts to the horizontal boring machine, but this time is made up for the processing and assembly stages. Dowel construction can be used to assemble drawers as well. 

A critical step to achieving the perfect look

When constructing a cabinet, one thing to consider is how easily and accurately the edges line up. This is critical for the cabinet’s overall look, especially if you intend to put crown moulding on the upper cabinets. Any misaligned pieces will undoubtedly show a gap. You can accurately drill the components vertically on a CNC machine with dowel construction.

The horizontal holes will have a fixed measurement from the edge to the center of the hole and are easily drilled at the CNC dowel inserter. This operation is very accurate. It is essential to use the same surface for reference to ensure accuracy. When you go to the assembly stage, the piece will line up perfectly on the top and the front. This will eliminate any gaps, and the result will be a very tight cabinet. Producing and assembling dowel case goods is very simple and does not require skilled artisans. A CNC router and CNC dowel inserter ensure accuracy and repeatability. When clamping the cabinet in a case clamp, you ensure that it is perfectly square. When installing cabinets side by side, they will line up extremely accurately without gaps.

The strength you are looking for

A goal of a cabinet maker should be to build a cabinet that will last. We use our kitchens and cabinets daily and store heavy items on the shelves, so they need to stand up to this daily abuse. When considering dowel construction, one should understand how durable this joint is. A study performed by FP Innovations investigated the joint strength of eight different construction methods. The dowel excelled at the shear, tensile, and parallel strength tests. Another independent study performed by Steve Morris, as found on Canadian Woodworking, explains that a dowel joint tested failed at 240 lbs pressure, whereas a biscuit joint failed at 100 lbs.

Ryan Akhurst is the Co-owner and Vice President of Akhurst Machinery, leading the fourth-generation family-owned company.

You might also like