The big thing about using steel cross dowels for knock down construction is that your layout must be absolutely meticulous. I have, and continue to use these a lot in jig construction, but there are a lot of other great applications.

While a lot can be done with these, a common application is for use in workbench base construction. Real life happens. People move, circumstances change. Sometimes the dream shop in the basement relocates to a garage or an outbuilding. Many of us cannot build a bench with the certainty of knowing it will never need to be easily transported to elsewhere at some future point. This makes the use of steel or brass cross dowels a wonderful option.

While this article is about what it takes to install cross dowels, due to popular demand I have researched and included links to what I feel are the best sources for this hardware in it’s various sizes out there. The links are included at the end of this article.

It is notable that bench building is enjoying a renaissance right now. some great new designs, vises and hardware packages have recently become available.

Amongst these offerings, a top of the line All Steel Cross Dowel Package has been made available by Benchcrafted. They are marketed as Benchcrafted Barrel Nuts, and they are the best product available to the bench builder. Unlike any other cross dowel meant for use with benches, these are all steel for heavy duty applications and the design allows the installer to align them with fingers during assembly. These are top quality, a great value and installation doesn’t get simpler.

Ok, if you already have your hardware in hand, then layout for cross dowels in knock down bench legs works like this. If you have not obtained the parts you need, please consider waiting until you have it in hand.

Lay your two legs and cross piece on the bench, Inside face facing up, already milled, mortised and tenoned, and dry fit them. Clamp them top and bottom to hold the unit together with enough force so that things will not move while you perform the layout, and check them for square. Make sure you have them square.

If you have a Veritas saddle square, or equivalent, that would be handy, but if you don’t, no matter, here is a work around:

Position the leg assembly by allowing it to hang over the edge of your bench and support it with a something like a telescopic roller stand. Take a six-foot length of string line and tie a nut or a heavy washer on each end for weight, and drape it over the leg assembly, along the centerline of the crosspiece. This string line forms somewhat of a double-ended plumb bob, which will indicate the centerline of your layout work and will project these lines around corners. You can eyeball centerline of your work piece or measure. Once the string is located, go ahead and put a piece of blue painters tape on each end near the corners where it drapes over the edge.

The best position for the cross dowel on the bolt is at the end of the bolt with all the threads in the nut fully engaged. The formula for figuring cross dowel hole location from any combination of length and diameter hardware is to take the working length of the bolt (which differs if the cap screw is hex head, allen head, button head or flat head) and subtract half the diameter of the cross dowel from that length to find hole centerline for the cross dowel. The length of the bolt, when you are choosing the length optionally, is best determined by the thickness of what it has to pass through on the bolt head side, plus 1-1/4 inches minimum into the adjoining board for cross dowel centerline.