Why these shelf joints?

A lot of the bookshelf and cabinet projects in Australian Woodsmith magazine use either of these joints for attaching shelves to the sides (glued only).

Attachment 259601

Most often the through dado is used when there is no face frame over the top, thus exposing the joint, and the rabbet is used when there is a face frame and the joint will be covered.

Why's that? Besides the apparently poorer aesthetics of an exposed rabbet, what are the features/benefits of either joint that makes them the choice in either situation? Why not just use a through dado whether there is a face frame or not?

AFAIK the rabbet is used at either top or btm (primarilly at the btm) of a cabinet although it can still be used at any other point but it is extra work when compared to the dado, the rabbet is used at the top or btm because there is a section of wood that is not removed in the sides giving mechanical strength that the dado wouldn't if it were used at the top or btm.

As far as a face frame used over one type of joint and not the other :?

Maybe someone else knows that one?

Maybe because the dado does look a bit better?



Pete

Just to put you right, they are (Housing Joints) not (Dado Joints) a Dado Cutter is one method of producing this joint

Usually the housing joint is stopped about 25mm from the front edge. The shelves, top and bottom are either checked by hand, on the jointer, router table, etc.

Aussie WS sources most of its projects directly from the American Woodsmith and Shopnotes mags, and massages the dimensions to convert to metric for our consumption. There are often pics of something being done with a Porter Cable fixed base router, a very rare beast here.

Our septic cousins like to base many of their projects around plywood, and make a big thing of their plywood not being precisely on thickness, it is often around 1/32in undersize but variable. They even have special plywood sized (undersized) router bits, but often they are not a good match to the undersized plywood.

In order to be able to cut accurate gap free joints for ply with a minimal setup and or need odd sized bits or adjustable jigs, they will typically cut the housing with a standard sized bit around half the shelf thickness to a depth of the bit diameter, then rebate the ends of the shelves to leave a tongue that accurately matches the housing cuts that they have made. Once glued up there are no obvious gaps present at the joints. Because this style of construction is based on ply, they use face frames to conceal the edges of the ply.

If they are making a project based on solid timber, they tend to buy the boards unsurfaced, and accurately dimension to requirements in the shop. They can then accurately match housings, bits and material thickness and can get away with cutting a standard width housing to accomodate their standard thickness material. Because the material is solid timber, they don't need face frames to hide ply edges, but will occasionally emply them as a design element.

Well that makes a whole bunch of sense. Silly 'mericans :q

Cheers Malb, and all. I can sleep easy now :2tsup: