Are 4xs useable for timberframing?

billyO · July 17, 2011, 10:29:23 AM

Hello all. I'm finally ready to begin practicing my joinery in preparation for my home remodel. I have access to a bunch of 4x12s (some 5x12s) from 8 - 14 feet in length and would like to use these to rebuild my tin well house and firewood shed. I'd like to use this inexpensive material for all parts of the practice projects (posts, girts, plates etc). Obviously I can rip/hew these smaller as necessary, and can make my longest span 6-8 feet if necessary (but would like longer if feasible). Again, the main purpose of these projects are to practice my joinery. My question, does a 4x have enough material to cut tenons and still maintain enough integrity to maintain joint strenght for minor load bearing uses (not much snow load where I live)?
thanks
billyO

Jim_Rogers · July 17, 2011, 10:49:01 AM

If you use square rule joinery, then where the tie meets the post, there will be a shelf or housing bottom for the tie to sit on. This will add to the strength of the joint.

Standard joinery rule say that the tenon for a piece has to be 1/4 the thickness of that piece. So for a piece of 4x material the tenon should be 1" thick. And it should be spaced off the layout face about the same amount, 1" . That leaves about 2" off extra material beyond the mortise if it was a tie entering a post.

Sometimes when we use a 4x piece we make the tenon 1 1/2" and lay it out 1 1/2" off the face. That uses up 3" of the piece with the leftover being about 1". That just about centers the tenon and mortise in the pieces if the mortise piece is also 4x stock.

Some people feel that a 1" tenon and mortise are a bit hard to cut as they are smaller then normal mortise and tenons.

About all I can say is to draw something up and post the plan for review in the plan section if you can do it with sketchup. If not, draw something up and take a picture of it to show what you intend to build for your well house. I'd be happy to review it and make some recommendations on your design.

Jim Rogers

witterbound · July 22, 2011, 04:09:49 PM

IMO 4xs are too small for anything but rafters or braces. Your going to end up with 1" mortices and 1" tenons. The smaller the mortice, IMO, the harder it is to cut, and you're going to need a 1" chisel, which you will probably seldom use on bigger timbers.

Your "practice" joinery is going to take a long time. When you're done, you want something you're proud of. I just don't think you'll be pleased with the result or the look, if you use 4x4s. You're going to spend days of your time getting the joinery just right. Why do that on something that's going to look wimpish when you get done? Spend a few bucks and get some bigger posts, girts, plates, etc. and use your 4xs for braces and rafters.

Brad_bb · July 23, 2011, 03:30:43 PM

Witterbound, he's not using 4X4's, he's starting with 4X12 or 5X12.

You'd rather start with 6X for the posts, but I think you can make it work. First, you should start out with the footprint you need/want, not let it be determined by that material. Define the dimensions you want and then go from there.