Alternative to cylindrical oak pegs for securing roundwood purlins to rafters?

I'm building the roof on my roundwood timber frame home. The rafters are roundwood. I was advised to slice the purlins in two so they lie flat on the rafters. Considering that I'll need purlins every ~30cm on 5-6 rafters of over 8 meters of roof, I will have a lot contact points which I want to join without nails, but with dried oak. I'm considering predrilling each joint with a small gauge and jamming in quickly made square oaks pegs, however, I wanted to ask here for more ideas because making cylindrical pegs would take ages...

Its sounds like a smart idea.
If you have a broad draw knife you may be able to make hexagonal pegs which would drive in easily c.w. square pegs,
If you make the pegs from material at least 300mm long and then cut then to length it should work.
Or can you use small branches as the pins?

I don't think I would use small branches (of any wood) for pins/pegs, as they will be mostly sapwood and weaker than riven pegs from a larger log. Cutting square pegs just a bit smaller than your hole diameter and roughly shaving the corners to make them gently tapered to octagonal might be the best way to go. If you do not have some sort of shaving horse/bench, you would be well served by making something to quickly clamp peg blanks for shaving.

With a clamp, you would need extra length to hold the peg while shaving, so I would make the blanks a bit more than twice the desired length, shave one end, then turn the peg around and shave the other end. Then you can cut it in two and have very little waste.

Thanks for the replies. I have access to 40+cm long pieces of dried oak, leftovers from making 1" dowels, from which I think I could make a few from one stretch

+1 for the concern about sapwood in smaller diameter branches. Pegs are super-critical to the strength of the frame and they are tiny. Use the cleanest-grained, best-quality oak you can get your hands on. You'll only need a little. It's crucial that you use properly seasoned, stable oak too. If you can keep it inside for a month or so before using it, to ensure the moisture content is as low as it'll get, it would be worth doing.

As for making pegs, it is always going to be a time-consuming process. John's idea about hexagonal pegs is a good one - you can always go one further and shave it into 16 sides and it will be as good as round.

Another suggestion would be to make up a jig to hammer the pegs through. I've attached a video of someone doing just that. It is essentially a tapered, sharpened tube made from decent grade of steel. I believe you need to roughly cut the pegs to fit before this though.

While your 1" dowel material is well dried, it might not be the most convenient size to start from for smaller pegs. What size of holes are you considering for the purlin mounting?

If you cut small peg material from fresh oak logs and shape it green (much easier), I expect you can dry those small pegs in a low oven overnight or so. The thin section will dry pretty quickly. I wouldn't try it with furniture-grade wood but construction-grade should be fine. A few warps or checks won't be a real problem.

So from the oak remains (the pieces left over after making 1" pegs) I've managed to make various pegs ranging from 10 - 15mm (5/8"). I thought at first the 1cm pegs might work like nails, however, on second thought I'd feel safer with 5/8" pegs where they fit. I have a metal plate that has templates for each of the pegs. Assuming, I can fit the dowel into my Makita screwdriver, I can turn on the hammer setting and work it through the template but unfortunately, for pegs larger than 12mm the end doesn't fit in the screwdriver and I end up having to bust the peg through the template with a mallet. It works but it takes longer.

Anyone know of any tricks to have a screw driver hold a peg larger than its mouth size?

I love that peg maker, its amazing!

Maruf Miliunas wrote:Anyone know of any tricks to have a screw driver hold a peg larger than its mouth size?

I can think of two options that might work.

1) Buy a larger diameter drill chuck. I'm sure that upgrades exist. Failing that, you could find a drill chuck with a larger internal diameter and mount it on a 12mm arbor and hold it in your existing drill chuck. This is the expensive and faffy option.

2) Use a mallet to make a small section of 12mm peg and then grip this section in your drill/screwdriver to create the rest of the peg. Cut off the small 12mm section when you're finished.