twisted timbers

We have started the 12x16 garden shed in Ted
Benson's book beginning with green doug fir. Completed the long and short sill beams and the floor joists. Just started the posts and the long sill beams have twisted. Timbers are now over a year old. How do we put it together without splitting out mortises or snapping off tenons? And how does one accommodate twists in a new piece at layout?

Jim:

Not knowing how bad the twisting is, it's hard to know what to recommend. You may be able to create a housing or open up the mortise to accommodate the offset tenons. There is very little stress on the sill joints, so if you can just make them go together (with a little slop) you might be OK. On the other hand if you can't join the sills so they lie in the same plane, you'll have to scribe all the posts so that you don't end up with a crooked structure.

Twisted beams can be accommodated in layout by the scribe rule method and to a lesser extent with square rule layout. For a good description of the two methods see the explanation at http://www.tfguild.org/ubb/Forum4/HTML/000003.html

[This message has been edited by Brian W (edited 05-05-99).]

Echoing Brian, where timbers do not have to carry wall, floor or roof surfaces, twist is less of a problem since joinery surfaces can be corrected locally. Choose axes for the stick which average out the twist, layout from centerlines and true up contact surfaces (faces, housings, mortises). Where a post, beam or rafter meets or carries floor, wall or roof planes, significantly twisted timbers (> 1.5°) are a nuisance and, in this framer's opinion, are best relocated or discarded.

[This message has been edited by Ed Levin (edited 05-11-99).]

[This message has been edited by Ed Levin (edited 05-11-99).]

How do I find the centerline and go about measuring the twist? Or any book titles?

[This message has been edited by piercejim (edited 05-11-99).]

[This message has been edited by piercejim (edited 05-21-99).]