dovetail template

[bic]

I'm starting the floor on my camp this spring, working on the bents now. I was considering dovetailing the floor joists into the sill. I'm looking for ideas on making a template for the dovetail, that fits on the joist then the sill. Dose anyone have any sugestions for this.
thanks ahead
Gord

[Jim_Rogers]

You should read up on dovetail here on this forum. Do a search here I have posted lots of information about them including pictures.

They are not the best joint to use due to the problems that happen when they shrink.

I don't use dovetails because of this.

Jim Rogers

[Jim_Rogers]

The only reason that you would use a dovetail joint to connect a floor joist to a sill is to hopefully prevent the sills from spreading out and moving apart from each other.

Due to the fact that the dovetail will shrink when it dries out which makes it looser in the dovetail pocket, which could let the sills move out is why I don't use them.

Most of the industry has moved away from dovetail joints because of this shrinkage factor that make the dovetail tenon loose in the dovetail pocket after it dries out.

A better joint to make to "tie" the sills together so that they can't spread out, is called a "tying joist" with a tenon and mortise.

When we create a floor joist we usually scoop out the bottom and create a curved cut like this:



In the above picture the joist is upside down to show you the curved cut on the bottom.

This is so that when you cut the drop in floor joist mortise into the sill that you don't take away too much wood out of the sill.



The above drawing show you the best way to figure out how much wood you need to leave in the sill so that it can support your joists.

Next instead of just cutting out a "drop in" floor joist pocket, you cut a tying joist tenon and it's pocket:



and it's pocket:



This joint holds the two sills together if you cut it correctly and peg the tenon to the mortise.

Hopefully this drawings and photos will help you.

Jim Rogers

[bic]

Once again Jim, thanks for your input. This makes a lot more sence. I guess I'm reading really old books.....

Gord