The Forestry Forum

General Forestry => Timber Framing/Log construction => Topic started by: Sidetrack on March 20, 2017, 02:54:08 PM

Title: First timberframe project advice
Post by: Sidetrack on March 20, 2017, 02:54:08 PM
(https://forestryforum.com/gallery/albums/userpics/45406/timberframe.jpg?easyrotate_cache=1490034368)

Hey everybody,

New to the forum and this will be my first timber frame project, and I'm looking for a little advice. I guess you'd call it an arbor, over a small 12'x12' second story deck. Material is nominal 4x stock, so 3.5in, top beam is a 4x6 and the ribs are steam bent and laminated 4x4s.

I've already got the uprights lagged and bolted in place, had to do that to get the siding around them. This looks like a good place to ask a few questions, an hopefully get some additional wisdom about avoiding any pitfalls I don't see. Happy to provide any more drawings or info, but here goes the initial questions:

A) is it reasonable to tenon the uprights in place with a circular saw, set to depth, and a chisel?
B) what's the most reasonable tool purchase to get the mortising done, plunge router?
C) the birds beak seemed like the most reasonable way to join the ribs, but is there a clean way I could extend the ribs out past the cap beams.
D) any suggestions for an unobtrusive tension member to keep the rib from wanting to spread under load out at the end (there's not going to be that much load though).
Title: Re: First timberframe project advice
Post by: timberwrestler on March 20, 2017, 03:22:49 PM
That's kinda cool.  Do you regularly steam bend or laminate things? 

You certainly can cut the tenons in situ, but it's not as easy as having them on sawhorses.  It's not the end of the world though.

I'd probably do a 1" thick tenon, so I'd just drill the mortises out with a spade bit or auger, and then clean it up with a chisel.  There's a goofy video of me out there on youtube doing just that.

So you have an inner birdsmouth there, but if you wanted an overhang, just raise the rafter.  I'd leave at least 2/3 of the rafter section, and the rest would just birdsmouth over the plate. 

For tension, you could use steel cable, threaded rod, or a steel rod.  Steel is good in tension, and you don't need much. 
Title: Re: First timberframe project advice
Post by: Sidetrack on March 20, 2017, 03:53:46 PM
Thanks, spade bits I've got, that's a lot cheaper than a new router and bit.

I've bent a few smaller things for boats, this will be the biggest I've done. Going to attempt to do it like this: https://www.youtube.com/watch?v=50uXPPt8-VI (https://www.youtube.com/watch?v=50uXPPt8-VI)
Title: Re: First timberframe project advice
Post by: Sidetrack on March 20, 2017, 04:11:30 PM
Something like this for the overhang? Looks like it would need some vertical dowels?
(https://forestryforum.com/gallery/albums/userpics/45406/beakoverhang.jpg?easyrotate_cache=1490040503)
Title: Re: First timberframe project advice
Post by: timberwrestler on March 21, 2017, 12:38:29 PM
Exactly.  And just stick 2 or 3 structural screws down, and you'll be good.  GRK RSS, Timberlok, Simpson SD, something like that.

What species are you planning on bending?
Title: Re: First timberframe project advice
Post by: Sidetrack on March 21, 2017, 01:05:34 PM
 

 (https://forestryforum.com/gallery/albums/userpics/45406/canted.jpg?easyrotate_cache=1490115319)

what would be the downsides of doing it this way? Non-standard and more complicated cuts, but no need for the screws? It lays out a little better under my existing rafters.

I've got some nice local straight grained and clear doug fir to bend, which let me use dimensional lumber store stock for the posts. I'm hoping I can stain and varnish up enough so it doesn't look like stock standard framing when finished.

Title: Re: First timberframe project advice
Post by: Don P on March 21, 2017, 10:21:52 PM
With a ridgebeam there really shouldn't be any horizontal thrust under load.