Forum Replies Created
5 September 2020 at 2:59 am #676840Steve SheenParticipant
Thanks for your advice Colin.
I have checked the walls. Actually I’m supposed to be making two of these for opposite corners of the same wall. One of the corners is 90 degrees while the other is a bit bigger. I’ll start with the 90 degree one. The shelves are more decorative than practical and will be fairly lightly loaded. I was thinking to screw them into both walls, either as you say in a couple of unobtrusive places or alternatively plugging the screw holes. I suppose 3/4″ stock would be thick enough for that. If I drilled to a depth of 1/4″ there would still be 1/2″ of would to grip against the wall.
I hadn’t thought of the stopped housing joint as an option. Any housing joints I have done before have been across the grain. In this case it would be long grain to end grain. The quarter-circle shelf piece would be long grain and the square side piece would be end grain. If I used a combination of stopped housing and dovetail joints as in your diagram, but re-orientated by 180 degrees, so the loaded shelf would be sitting on top of the side piece rather than working to pull the housing joint open and the dovetails, would that be stronger? Or does it not really make a difference if the joint is well-fitted and glued up properly? Would stopped housing joints on both pieces be just as effective?
(This kind of relates to something that confused me about the wall-mounted bathroom cabinet project. If I recall correctly this also used the stopped housing joint to join the two sides to the bottom (housing grooves cut into the bottom piece). From a mechanical perspective, the housing joint has one weak direction. Any sideways forces will not open the joint. An upwards for will not open the joint. But a downwards force (in the case of the bottom of the bathroom cabinet) would act to open up the joint. So the strength of the joint depends on the glue. Whereas if the housing grooves were in the side pieces and the bottom fitted into the sides, there would be extra mechanical strength in the direction of loading. I suppose in the case the bathroom cabinet was not going to be under heavy load so the design becomes a pay-off between strength and aesthetics. The cabinet certainly looks better the way Paul designed it and is strong enough for the purpose. I find this element of designing projects almost as interesting as the making!)
Thanks a lot for your time and suggestions. It has been a big help.