Tag Archives: Joiner’s Shed

Treenails, Trunnels, Pins and Pegs

Treenails, Trunnels, Pins and Pegs — all terms used to describe the wooden nail-like fastener used in timber frame construction. I needed to make a large number of them for an upcoming project and thought you might also enjoy seeing what it takes to make these deceptively simple looking pins.

White Oak and Hard Maple stock ripped, thickness planed and jointed
(1) White Oak and Hard Maple stock ripped, thickness planed and jointed

Where did all those names come from?

Like most things that predate modern recorded history I’ve read many conflicting theories on where these terms came from, so what I relay here is based on my own experiences in this field; your mileage may vary. Timber framing dates back thousands of years and can be found in early civilizations around the world in many different forms. What all these structures had in common was the joining of heavy timbers using traditional joinery and large mortise an tenon joints that were pinned together using large wood fasteners.

These fasteners are known by a lot of colloquial names, the most common of which I describe in this post. Most literally treenails (or trenails in some places) is the term for nails made from a tree. Trunnels is derived from the pronunciation of treenails and at times reserved for larger treenails used in very large buildings or ships, sometimes even wedged so they do not back out. Pegs tends to be a more modern term for treenails and pins tends to be used for smaller scale work though many timber framers I know today use it regularly. Having said all this I’ve heard all of these terms used inter-changeably at times by both novices and seasoned professionals, so feel free to use the term(s) that best suit your work and locale.

The bottom line is ‘a pin by any other name will hold your building together just as well.‘ (provided you heed my tips below 😉 )

Stock ripped down into square blanks
(2) Stock ripped down into square blanks

How do you go about making these pins?

Traditionally pins were split out of green wood, shaved down with a draw knife and shave horse and allowed to season. Then touched up again when dry. Since I have to make a few hundred of these, being a practical modern joiner I will make use of my table saw and some high quality kiln dried lumber. Most of the stresses in a timber frame are carried by the joints and not the pins, and white oak is very resistant to shearing forces so I am not worried about the wood not being split out for this usage. (I’m building a square rule, late 19th century style frame from milled eastern white pine, so by that point the pins likely were made the same way I go about it)

For the scale of timber framed buildings I generally work on — homes, barns and sheds, I’m usually using a 7/8″ ships auger bit to drill holes for pins. Most tenons I work with are generally 1.5″-2″ thick eastern white pine and based on experience and reference tables I’ve found this size to work well for me.

I learned to timber frame while at NBSS and with that my framing has a proclivity for historic precedents. The historic buildings I work on all had octagoned pegs which worked well for hundreds of years and can be made more easily when compared to the expensive turned pegs you see some modern supply houses offer for upwards of $2 each. For a draw bored joint, I feel the octagon pegs look better and hold better compared to the CNC turned pins. (More on that later)

Making octagons out of the square blanks
(3) Making octagons out of the square blanks

1.) I start off by milling down my rough 4/4 white oak stock to be 7/8″ thick, then I joint an edge on each board (See photo 1). I then crosscut each board to be about 30-3/8″ long. (Each of these boards should yield 3 sets of 10″ long pegs)

2.) Next I rip each of those boards into 7/8″ square sticks (See photo 2)

3.) Tilt the blade on your table to 45″ and turn each of those square blanks into an octagon. The use of feather-boards will help you be consistent. (See photo 3)

Chopping several blanks at a time on the chop saw using a stop block
(4) Chopping several blanks at a time on the chop saw using a stop block

4.) I set a stop block on the chop saw at 10″ and gang chop (cut several at a time) for the sake of efficiency (See photo 4)

248 Oak Treenails and 166 Hard Maple Try Pins
(5) 248 Oak Treenails and 166 Hard Maple Try Pins

5.) At this point you’ll quickly see how many pin blanks it takes to make even a modest building. (In this case a 12’x24′ large shed/small barn) (See photo 5)

Using the hewing bench, carpenter's axe and timber framing chisel to taper the ends of each pin
(6) Using the hewing bench, carpenter’s axe and timber framing chisel to taper the ends of each pin

6.) Now it’s over to the hewing bench to taper the leading ends of the pin blanks. I usually rough off the wood with my capenter’s axe and touch things up with a timber framing chisel. I find it helps to get the cut started with the tool and bang them both (peg and tool) in unison on the hewing bench. The downward momentum drives the tool through the wood with a minimal expenditure of energy — important when you have a few hundred of these to complete.

Completed pins
(7) Completed pins

7.) I usually taper the first 2″ or so of the pin. You do not need to be overly concerned with trying to make the pins look like a sharpened pencil. You just need to knock off the corners to help guide the pin through the draw-bored joint.  Anything beyond that is to suit the design aesthetic you are going for. (Some folks will want to cut the ends off a pin in the house, so all the more reason to only do what you need to do with them)

Foreground -- 3/4" Hard Maple Try Pins; Background 7/8" White Oak Treenails
(8) Foreground — 3/4″ Hard Maple Try Pins; Background 7/8″ White Oak Treenails

8.) Sit back and enjoy your work. Take a deep breath and repeat steps 1-7 all over again to make try pins. Try pins are slightly thinner pins used when test fitting your timber frame. I make them from hard maple for two reasons — I can visually differentiate them from the oak and the smooth hard maple is easily removed when the test fitting is complete. For this frame using 7/8″ Oak pins I make the try pins from 3/4″ hard maple stock. They are made the same way as their larger brethren.

Full buckets of pins
Full buckets of pins

Why are they octagons?

By making a 7/8″ octagon pin and driving it into a 7/8″ round hole the corners will bite into the wood and keep the the pin securely seated.  (The diagonals across the 7/8″ octagon are slightly longer than 7/8″.) This is why you want to use smaller try-pins during test fitting, this way you are not deforming/stretching the holes before the frame is raised.

Driving in the pegs
Driving in the pegs

Tips for a high quality timber framing pin:

  • Use kiln dried pins with a green wood frame. Use green pins with a dried frame
  • I use most often use White Oak pins with green Eastern White Pine frames
  • I use Hard Maple Try Pins during test fittings (try pins should be 1/8″ smaller than your final pins)
  • Octagon your pin stock so that it properly bites into the joint
  • Taper the ends of your pins so they will easily enter the draw bored joints
  • Don’t stress too much about the tapering
  • Avoid the machine turned pins — I dislike the look, the cost (~$2 each), holding power, fact that they are not historical etc
Many pegs in a timber frame
Many pegs in a timber frame

Where can I learn more about timber framing?

  • Join the Timber Framer’s Guild (www.tfguild.org) and read the many good publications they have
  • Read any of the books by Jack Sobon, Ted Benson or Ed Levin on the topic of Timber Framing
  • Take a class in timber framing at The North Bennet Street School (with Rich Friberg or me), or at the Heartwood School in Western MA

The next time you are in a barn or timber framed building I hope that you will take a moment to examine the pins holding the joinery together.


The thoughts one thinks while sawing a tree…

“The Oriental philosophy of contemplation involves forsaking all work; the European does his meditating while relaxing from work, but the American seems to think things out best while working. So the stone walls of New England may be thought of as monuments to the thoughts that occurred while they were being built, for those were the days of great decisions and profound planning. The thoughts one thinks while sawing a tree or making a stone wall are surprising. It is almost as if the mind becomes ashamed of the work the body is doing and starts doing a little “showing off” by itself. Lincoln said he did some of his deepest thinking while splitting rails. The plain farmer of two hundred years ago was weaving the fabric of a new nation and although there are no marble statues to his patriotism now, there are still his stone walls.” — Eric Sloane American Barns and Covered Bridges, 1954

Oak trees in the way of my barn...
Oak trees in the way of my barn…

I live on a heavily wooded street in New Hampshire that is lined with stone walls. As I pass them each day I think about what it took to clear all this land and build those walls. While most of the neighborhood is covered with second and third growth trees that were not actively managed, and new housing developments,  there are still a few pockets of small family farms with cleared farmland that looks like an idealistic painting of yesteryear and reminds us how this was all farmland about 100 years ago.  As the leaves changed this season I found it amusing to see tourists snapping pictures in front of some of these farms with their stone walls and weathered barns. In the book referenced above Sloane encouraged his readers to keep an eye out for early barns also made several interesting observations about stone walls. They were designed to keep animals in and not to keep humans out. When a wall fell over you had all the stones needed to rebuild it as opposed to a wooden fence that could have rotted away. I like the sense of inviting simplicity, using what you had on hand and building for the long term.

I recently set out to clear some trees out of my backyard and make room for a 12’x24′ timber framed shed/small barn to store extra wood and yard equipment. I’ve cleared about 35 trees so far, knocked off a bucket list item — taking down a full size tree with a felling axe, and still have a few more to go.

Felling oak trees
Felling oak trees

Safety Tip:

When working with large trees and high powered saw, make sure to ALWAYS wear the appropriate safety gear. Above you can see me wearing my steel toe boots, Kevlar chaps, eye protection, helmet with hearing protection and face shield and Kevlar reinforced gloves.  The chaps are like wearing an insulating blanket and rough to wear in the summer, but in cooler months they help you stay warm.

Limbing the tree
Limbing the tree

How do I cut down a larger tree?

I start by walking around the tree from all sides, sighting up at it to see what way it leans and were the mass is held by the limbs. I then mentally think about what direction I have enough space to drop to the tree without hitting houses, other trees, people or fences. With a plan in place I set about felling the tree. The process is much the same whether I use an axe or a chainsaw. I cut in at an angle on the side of the tree facing the way I want it to fall. I then make a horizontal cut to remove that wedge of wood. It should only be about 1/3 of the way through the tree. You want the intersection of those two cuts to land right on each other so you have a smooth hinging surface and a controlled drop.

90 Foot tall oak trees take a LOT of work to break down
90 Foot tall oak trees take a LOT of work to break down

I then come from behind the tree and make a horizontal cut until I leave about a 1.5″” wide hinge of wood that will help control the fall. This cut should be about 2″ above the bottom of the wedge cut (As seen in the photo below).  If done properly the tree should slowly start to fall over exactly where you want it. The tree shown here was a 90 foot tall oak, so when it hit the ground it shook the ground with an incredible thud — anything in it’s path will get crushed. When cutting a tree like this make sure you have a clear retreat path, usually 45 degree from the way you expected the tree to fall, that way you are not in the path of a falling or splitting tree or anything it kicks up.

Notch cut and hinge used for a controlled drop
Notch cut and hinge used for a controlled drop

Once on the ground I start removing all the limbs from the tree. I start with all the limbs that are not holding the trunk up off the ground to make room to better access the trunk. Any limbs or branches that are holding up the trunk are likely going to bind on your chainsaw if you are not careful. Being mindful of where the tree may move as you release that tension you can use a sharp axe to remove these limbs or careful wedge cuts that will not bind the saw. When doing this sort of work you need to be thinking about where the trunk is likely to fall after removing this limb, so you’ll want to mind your legs and feet.

Breaking down the de-limbed tree into firewood
Breaking down the de-limbed tree into firewood

Once the limbs are removed I break the tree trunk down into either firewood or whatever I am looking to use the wood for. These trees will be processed down into several projects — a few bowl blanks, a new base for my anvil, a few chopping benches for the shop, a stump to split firewood on and of course firewood. The incredible amount of brush and branches will be ground up into chips and distributed elsewhere on the property.

More Tips on cutting trees:

  • Try to cut tree during the colder months or winter as there will be less sap and thus less weight and cleaner cuts
  • Use plastic wedges when cutting a larger stump so that it does not bind on your saw’s bar and the wedge will not damage the chain
  • Use plastic or even larger metal wedges to help a cut tree (notched and ready to hinge) that is not falling. You can use a large mallet or beetle to drive in a wedge and help give it that little push it needs to start going over.
The result of a weekend of hard work
The result of a weekend of hard work

Even with all of the above information running through my head, and the sometimes backbreaking labor to break down these trees, there was still a lot of time to think. As I was doing the above work I was building the timber framed barn over and over again in my head, so by the time I actually get around to cutting the frame it will be like second nature. Unfortunately the snowy weather is creeping up on me fast, so it will be a race to see if I can get the shed put up this fall/winter or if it will get delayed until spring.

I’ll keep you posted.

Take care,
-Bill Rainford