Tag-Archive for ◊ carcase doweling ◊

Author:
• Wednesday, June 30th, 2021
shopmade dowel jig

It is reasonable to be skeptical of dowel joinery. After all, half the joint involves gluing the long grain of the dowel into a hole where the glue surface is partly end grain with limited true side-grain glue surface. However, the carcase dowel joint, used in the right circumstances and made properly, works and lasts without doubt. Joints in pieces that I have constructed as long as 20 years ago and have been able to observe since are still cleanly tight.  

We associate this joinery with the late James Krenov who wrote about it in detail in The Fine Art of Cabinetmaking. Here my attempt is to humbly add tips and refinements, particularly toward ensuring accuracy.

Making the jig is more than half the job for this joint. Use a very hard, fine-grained wood that will hold clean, sturdy holes to last through repeated use, including inevitably repurposing the jig for future projects. I have long used bubinga, though its availability is now limited. Your shopmade jig will be at least as accurate as manufactured jigs of this type, and it will be customized to your project. 

dowel jig

I usually make the block about 1 1/8″ thick (in the direction of the length of the holes) and about 1″ wide. The width does not need to match the width of either workpiece but will, in fact, be a little wider than the end grain workpiece to ensure good seating on the side-grain workpiece. The length will usually be a little longer than the width of the workpieces.

Employ every effort to make the block with two absolutely flat surfaces that are dead parallel to each other. This is critical because the jig will be used to drill from both directions. Any error in parallelism will be doubled when making the joint. 

A third face, the reference face, should be flat and dead square to the two faces with holes. The fourth face, which I mark with a big “X”, is not critical.

The holes should be drilled with a well-tuned drill press. This is cross-grain drilling, so a good brad point bit is the best choice. 

dowel jig references

A small, removable cleat on the end of the block serves as a physical reference against the workpieces. This can be augmented depending on whether the workpieces meet flush at their edges. 

Krenov’s description shows the block being nailed to the end grain workpiece, using the tablesaw top as a flat reference. I do not like this method. Instead, I use a removable side piece to reference the jig on the end grain workpiece. The jig is attached with two #8 screws going through countersunk clearance holes and penetrating the workpiece only about 3/8″. The jig is attached to the side-grain workpiece without using the side piece but instead squared and clamped to the workpiece, and then screwed in place. 

Below, the jig is placed on the endgrain workpiece using the back cleat and side piece to ensure solid referencing. (I have not screwed it in place for the photo.) Note that both the end cleat and the side piece extend beyond both hole-faces of the jig. This allows the jig to be used at both ends of the workpiece.

dowel jig in place

I mark up the jig all over: “back,” “Reference” face, “X” for the non-reference face, the size of screws to use, the drill bits to use, etc. 

Now, more than half done, next we’ll look at designing the joint, dowels, drill bits, etc.

Category: Techniques  | Tags:  | 11 Comments
Author:
• Monday, May 31st, 2021
carcase doweling

Consider the options for joining solid wood boards across their widths where the endgrain of one board meets within the length (not at the end) of the side grain face of the other. This is what you see in the pieces above and just below, which are constructed with dowel joinery.

A common situation is joining the sides of a cabinet to the top and bottom where the boards do not meet at the end of each. If they did, dovetail joinery is usually the best choice. Another common situation is an interior divider or fixed shelf of a cabinet or bookcase. 

carcase dowelling

Before delving into the topic of this series, here are some alternatives that might be used in the same situation as carcase dowelling. By the way, this series is not about post and rail joints with dowels, a different matter with its own considerations. 

1. The multiple wedged through mortise and tenon. This has plenty of side grain glue surface and the flared mortises coupled with the wedged tenons provide a mechanical lock. It does take a lot of work though, and the exposed wedged tenons may be a nice feature or unwelcome. The blind version of this joint is an exercise in masochism.

For an efficient method for this joint, see my article in Popular Woodworking, issue #170, August 2008, pages 62-65. 

multiple wedged through mortise and tenon joint

2. The tapered sliding dovetail. This provides a strong mechanical lock, and can be made efficiently with careful router setups and a bit of fine tuning by hand, though it does take some trial and practice to get it right. It can be designed to be invisible but only at one end. 

3. Nails and screws. We do not usually associate this approach with fine woodworking but not everything has to be high end. I have a 44 year-old large bookcase held together with nails and it is still rock solid. The nails are hidden (mostly) with the technique of raising an attached chip, driving the nail inside the tiny ditch, then gluing down the chip. I can do better now, but it’s not bad. 

Covering the heads of screws with side-grain tapered wood plugs is a decent option in plywood and could pass in solid wood utilitarian work if done judiciously.

4. Hidden knockdown fasteners such as cam fasteners. Nah, not where I want to go in solid wood; weak. 

5. Dado joints, fully housed or shouldered. Here we have no mechanical lock and no mating of side grain glue surfaces. Biscuits or dominoes would help but I still would not bank on the strength. 

OK, with the other options noted, let’s go ahead and look at the carcase dowel joint. Part 2 is coming up. 

Category: Techniques  | Tags:  | 2 Comments