northwest pegs?

any advice on the best peg material in the pnw? i want to make my own pegs, just not sure out of what. thinking about bigleaf maple. what about pegging with the same wood you have framed with?(d.fir)

I have been using Western Tamarack of late. It rives well.

Hi, Andrew -
I have only ever used dry oak pegs, but I think other hardwoods would work well.
I would advise against using softwood; it is, after all, soft. And by using the same species your wood will shrink in the same fashion.
If using green timbers, the wood will shrink around the hardwood peg, creating a super tight joint. Even if the hardwood peg isn't completely dry, it will shrink at a slower rate than the softwood, and not as much.

Anecdote time: There was a guy here trying to de-construct an old TF barn - he couldn't get the pegs out...so he took his chainsaw to all the joinery . Yes, very unfortunate, but it was constructed with green D.Fir and oak pegs, and was meant to withstand time. (Time, not chainsaws)
*K

so, is that good?
shouldn't it be possible to deconstruct a frame without damaging the joinery?
should pegs be super tight?

Hi, Mark-
The guys that I've learned from all seem to stress the importance of tight joints, so that's what info I can give.
The more we share the more we know. I would love to hear more about the different perspectives on this topic....
What's yours?
*K

I was always told to use green pegs, and to store them in a bucket of water if they were going to sit for a while. I guess the reason is that when you are drawboring you need the flexibility of green wood. It is too bad that person just cut the frame apart. There are ways to get stubborn pegs out. I have a slide hammer with a lag screw on the end that works well. I also have made pins with depressions on the end to drive the peg back through the hole.

Dave

Here is a story I tell from time to time.... My cousin's barn got hit with a hurricane back around 1950, hurricane hazel, I beleive. The hurricane ripped the roof off the barn, but the frame(including most of the rafters) stayed up and stayed square. We recently took that barn down and I was amazed to see that the mortise and tenon joints had 1/2" gaps inside. Very loose fit on the tenons but the shoulders were tight. Why did this barn not blow down? Could be good design/luck/ability to flex/great wood... but not tight joints. Seeing this frame changed my own attitude toward joinery, and I now wonder how crucial tight joints are to strength.

i have access to kiln dried oak that i could cut 1x1 pieces out of and then taper into pegs. this is what i intended to do until i read in sobons book that pegs should be made of green wood. the d. fir timbers i'll be working with will be pretty green. the logs are on the ground now, and i'll be milling them soon. hopefully be ready to raise in 4 or 5 months. will a kiln dried peg be suitable, or should i go for fresh cut?

The purpose of using "green" peg stock is to ease the work while riving and shaping the peg stock on the shaving horse. After that it is wise to let them dry for a time.

I have surveyed historical timber frame structures that utilised soft wood pegs with no ill effect.

Softwood does not necessarily mean weak and Hardwood does not necessarily mean strong, as is evidence by reading the wood species strength tables.

The rate of shrinkage would depend on the initial moisture content of the individual species at the time of felling.

A hardwood can shrink as much or more than a given softwood.

I rive "green" Inland Western Tamarack that meters out around 26%. The shrinkage is much less than the Ohio Oak I have used that metered above 40%.

Machining peg stock is not as suitable as riving due to the short grain run out that occurs.

On another note: It is prudent for the West to create its own relationship and timber frame vernacular based on our available species; both for framing material and peg stock.

I heartily advocate familiarising yourself with the local woods and utilising what is there.

Good practice dictates that we design frames and joinery that do not rely upon hardwood or softwood pegs for strength. Specifically in tension joinery.

thanks for the feedback, everybody. colin, you've made some good points. i like the idea of the materials all being native to the area. all the wood for my project has come from my land so far, and i would like the pegs to as well. mostly conifers here on my place, but there's some maple and a handful of alder. ever seen an alder peg?

Based on peg research:

The general rule is the peg needs to be hardwood, straight grained, and of an as-dense or denser species than what you are pegging. Alder is too soft, but I am not too familiar with bigleaf maple. If you check with the "wood handbook" and compare specific gravities of the maple versus the d.fir, you should get an idea if it is ok.

Joe

All the old frames around here that I have seen use the same wood for the pegs as for the frame -- old growth Longleaf Pine (heart pine. It is a great peg wood -- straight grained, tough, strong, stiff, and hard. Today's pine, though, is no more suitable for peg stock than closet rod is.

Also the way some of the pegs are deformed by the draw bore make me think they were driven fairly green.

I agree with Colin. Pegs are not suitable for tension connections and were rarely successfully used for such joints in the past.

Good luck with your pegs Andrew.

Cheers,

Gabel

Andrew

I think you are getting a lot of good advice but if you are looking for a local hardwood we don't have that many choices in the Puget Sound basin.
According to the Forest Service (whose focus is commercially valuable timber) the choices are;
Red Alder
Oregon Ash
Western paper birch
Black cottonwood
Pacific Madrone
Bigleaf maple
Willow

Alder would be my last choice as a building material; it is soft (for a "hardwood") brittle and anything but straight grained. And if used outside it can be called by another common name…compost.

Of the list above my candidates would be Ash, Birch, Madrone (Arbutus for our Canadian buds) and Maple, probably in that order for strength and straight grain. The Ash, Birch and Maple are all species that you should be able to find in the Skagit valley as they are low elevation/river bottom trees.
The Madrone grows closer to salt water, the folk wisdom being that it must smell the salt.
Madrone would be my choice for appearance; it has a beautiful butterscotch color. You do want to work it green, once dry it is very hard.

There is a species of oak in the region, the Gary oak, but this is associated with the south sound prairie ecosystem and is very limited. And for that mater probably endangered in the area

You might also find Black locust which is a none native invasive species with excellent characteristics, one of which is someone will be happy to part with it.

Good luck

J.E.B.

hey guys, thanks a lot. i'm glad to see this topic has generated some interest. right now, i guess i'm leaning towards maple cause i know i can cut one fresh. a friend scored some black locust last spring that they culled out of the state park up here; but i want to try and keep the material close to the same "age." john, have you worked with madrone much? it seems awfully twisty. thanks -ac

Andrew

I have worked with madrone, but I haven’t used it a lot. It does have stability problems but I doubt they would be a factor with pegs.
It occurs to me that it might be prudent and would certainly be interesting to do some experimentation with the different species. You could test for shear and "drivability" (does it shatter when driven)

J.E.B.

Mark, very interesting ideas on the "not so tight joint"! You made a light bulb go on in my timber brain. Thanks. tb