sizing joints on 2x4's, 1x1's

[canopy]

Sometimes I do small wood working projects and like to apply timber framing skills as much as I can. The general rule of thumb for timber framing is tenons are 1/4 width of the wood. Does this formula apply to smaller wood? In other words is a 1/2" tenon ideal for joining 2x4's and a 1/4" tenon ideal for joining 1x1's?

[Jim_Rogers]

I would think that all depends on the load being applied to these tenons.

[Axe Handle Hound]

The standard for woodworking is the 1/3 rule.  1/3 of the thickness is a tenon cheek, 1/3 is tenon, and 1/3 is the other tenon cheek.  So if you're using nominal 2X lumber a 1/2" tenon should be okay.  If you're using true 2X material it may be a bit thin. 

[routestep]

I agree with the 1/3 for thickness.