The Forestry Forum

General Forestry => Timber Framing/Log construction => Topic started by: Flekoun on August 23, 2021, 03:16:46 PM

Title: Drawboring or not?
Post by: Flekoun on August 23, 2021, 03:16:46 PM
Hello folks. I have finished by first timberframe joinery and now I need to make pins and decide if I want to do a drawboring or not.
I am not sure if it is worth the effort as drilling the holes on assembled timberframe looks much more straightforward and error free.
Also want to ask if I can use dried  hardwood instead of green one for drawboring as I am a little bit affraid if the pins wont tend to break instead of bending.
Thanks.
Title: Re: Drawboring or not?
Post by: Andries on August 23, 2021, 05:04:47 PM
The 'frequent timber framers' seem to have common recommendation of: green timbers and dry pegs. 
Theory holds that a strong dry peg will pull together the joinery when hammered in, and then the timber's drying will shrink around a dry peg,  kinda locking the joint together. Drawboring is an extra step, no doubt, but it will lock the joinery as soon as the Peg is in, rather than when the timbers dry down to EMC.
However, @Jim (https://forestryforum.com/board/index.php?action=profile;u=1052) Rogers or @Don P (https://forestryforum.com/board/index.php?action=profile;u=17) will have construction and de-construction recommendations based on far more experience than I can offer.
Title: Re: Drawboring or not?
Post by: Dave Shepard on August 23, 2021, 05:25:45 PM
Pegs should be dry enough to not mushroom when you hammer them, but no drier. If you assemble and drill the tenons with green timbers, the joints will loosen as the timbers shrink. 
Title: Re: Drawboring or not?
Post by: flyingparks on August 24, 2021, 05:07:03 PM
If you don't draw bore, you'll wish you had.
Title: Re: Drawboring or not?
Post by: Brad_bb on August 27, 2021, 10:43:24 PM
Both ways work.  If you do not draw bore, make sure your drill bit and peg size match up well.  Most use a wood owl bit.  Some people use dry pegs from Northcott, but you can make your own and use a sizing die.  I have done that mostly and only used Northcott when short on time.  I drive it though a simple steel die (3/8" flat steel stock with a 1" hole drilled in it).  You can draw knife home made pegs blanks, let them dry out completely, then drive them though the die twice.  The first time they get compressed as well as shaving them.  The second driving will shave them without compressing.

Driving a peg will have a particular feel/resistance/friction when sized correctly without getting stuck or going through too easily.
Title: Re: Drawboring or not?
Post by: Don P on August 27, 2021, 11:09:12 PM
In a talk Ben Brungraber gave he said if you are going to drawbore use a more flexible 3/4" peg.
Title: Re: Drawboring or not?
Post by: Brad_bb on August 30, 2021, 11:46:12 PM
In a talk Ben Brungraber gave he said if you are going to drawbore use a more flexible 3/4" peg.
I guess we'd have to define what we are talking about.  The draw bore pegs I've made start at 1" x12" and are tapered for 3/4 of their length down to about 3/8.  The holes are 1", but how much peg diameter is there at the point of contact? Maybe 3/4"?  If you start with a 3/4" hole and peg and taper it down, how much diameter is at the shear points?