wood movement in dovetail

[Michael MacDonald]

Usually I have seen dovetails that are end-grain to end-grain. Any reason I can't put an end grain pin into a tail on the side of a board... if the pin board was only perhaps two or three inches wide? (dealing with 3/4 thick stock)... perhaps this is a trivial question--no reason to think it is differerent than the average M&T joint? which usually have conflicting wood-movement orientation.

I figure if I were to dovetail the end-grain of a wide board (e.g. 20 inches) into the side of a tail board, the side-to-side wood movement of the pin board would eventually cause the pin board to split because the tail board would not move with it... at the larger width there is a significant difference in the wood movement. But I am hoping that with smaller boards, the different in wood movement is not material. now that I write it out, it seems I am overthinking this... should be just like any M&T joint. anyone disagree?

[James Phillips]

You see it done the otherway (end grain tail into long grain board) pretty often. It will be fine if it is not to wide

[Michael Peet]

I'm having a little trouble following, but if this is what you are talking about I would be worried about the tails breaking off where the red lines are:

180480

Mike

[Michael MacDonald]

Michael Peet - that is exactly what I am thinking... only one pin instead of one and two half pins. I was actually worried about a split along the line where you indicated grain direction on the pin board. but I see what you are saying about the red line... with one pin, I might see a split beginning on either side of the pin.--would this be true even if the stock is 3/4 thick?

good job illustrating my thought--I was too lazy to draw, post and attach. thanks for doing that.

[Michael MacDonald]

actually, I also had the need to revers the pins and tails in that diagram... as I think about it, reversing the pins and tails seems less dangerous with regard to a split... more like a normal mortise-and-tenon where the stress will be.

[John A. Callaway]

wouldn't you just use the lap DT instead ?

[Michael MacDonald]

is lap dovetail a half-blind dovetail? not sure of that term... I haven't heard it before. If not a through DT, then the risk of splitting would be a lot lower?

[John A. Callaway]

scroll down to figure 293

http://sawdustmaking.com/woodjoints/dovetails.htm

a better example would be the lower right pic on the right side of this page

http://en.wikipedia.org/wiki/Lap_joint

[Michael MacDonald]

OK... I see what you are saying... yes--that reverses the pins and the tails in the picture in a post above. That is an option, but locks the joint from movement in a different direction. I have need for both types, but the lapped dovetail joint appears to have less risk of splitting, so I will be using that.