Comment by arturocamembert | Hacker News Reader

Comment by arturocamembert | Hacker News Reader

Parent Full thread

arturocamembert

Small addendum: some traditional wooden joinery is deliberately prepared to account for the varying rates and effects of drying across the timber.

This is particularly relevant in timberframing, where you want to work with the wood when it is as green as possible. Green pine, though heavier to lug around, is significantly more receptive to a chisel than drier lumber. In a classic mortise and tenon joint [0], it's common to leave the outer edge of the shoulder slightly raised from the inner edge to account for the natural warping as the exterior of the beam dries more aggressively.

Although it's more outside my area of experience, I believe fine carpentry also has a few techniques that see a higher frequency of use in areas that enjoy seasonal swings in humidity. The split-tenon is the only one that comes to mind, but, now that I think of it, I realize my mental model isn't great. More surface area to account for seasonal swelling / shrinkage? Maybe someone else can chime with a better explanation of this one.

[0] https://www.barnyard.com/sites/default/files/styles/full_pag...

Timber framing uses dry wood as well, slightly different techniques but in the softwoods and some of the hardwoods its is not all that harder to work dry than green and in some ways easier. It depends on the tradition and location as to the exact process and technique, some preferred dry timbers, some green, some something between.

In US farm country it was common to fell the trees in late fall/early winter after the harvest was all taken care of and then leave the trees where they dropped until the ground froze. After the ground froze you haul them to the build site, much easier to drag logs on hard frozen ground than on soft wet ground. Then you would forget about them until after the spring planting is taken care of and build in the summer. Those big timbers would be far from dry but they will have lost a fair amount of weight and will be more stable which makes everything easier.

I read a biography of the earthmoving equipment maker R.G. Le Tourneau, and it was really eye-opening how much this was a thing before mechanized equipment was readily available. A lot of moving was put off until winter because it was so much easier to drag logs, boulders, buildings, etc. over ice than over thawed ground.

Or waiting for things to freeze real good so you can dig the kind of hole or trench that would make HN clutch its pearls or simplify de-watering problems.

I’ve never tried to dig in frozen ground - isn’t that going to require blasting equipment or techniques closer to mining? (Heavy pneumatic jackhammers)

Well, in the era we're discussing, there wouldn't be jackhammers. Mainly a bunch of guys with pickaxes.

Generally you just build a fire on the ground you want to dig up, possibly throw in some good sized stones to hold the heat longer. If the frost is deep might turn it all over once the flames have died down and bury those coals and stones so their heat is more contained and not just going up into the air, or have a second fire after you have dug out the thawed soil.

I can only speak to my own experience of doing this professionally in northern climes without power tools for ~5 years, but both of your suggestions are foreign to me. I take this as a nice reminder that there is lots of regional variation to this craft around the world, which isn't surprising.

Even then, building a barn with dried pine or hemlock is much more tedious and incurs many more trips to the sharpening wheel. It is in no way easier.

The joints used in dried are dictated by the operations which are easier to do in dry wood and are not influenced by what the wood will do as it dries. Dried you get to use a saw with considerably less kerf and a thinner plate, augers can be more aggressive and take better advantage of lead screw and spurs. Chisel work will be a bit slower when chopping across the grain but not harder and if it incurs many more trips to the sharpening stone you are most likely trying to chop that mortise as you would in green wood.

Green woodworking is an entire field of its own. Not very common in industrial scale but it was a common method a few centuries ago.

Examples of things where green woodworking is common: spoon carving, bowl turning, chair making, etc.

The idea is that wood is worked while green to make 80% finished blanks, which are dried slowly for some months or years before finishing the rest of it. This gives less distortion to the shape as it dries. And the drying times are faster because it's all small pieces at that point. The time from tree to product is shorter.

It is an almost extinct craft but it is a lot of fun for woodworkers not under schedule pressure.

I just finished a green wood post-and-rung chairmaking class last week. The posts are split out and steam-bent, while the rungs are dried in a makeshift kiln (a box with a heat lamp). The posts are then above ambient humidity, while the rungs are dried below it. As the entire chair equals out, the posts will dry out and compress onto the tenons of the rungs, which will swell up a bit and lock in place. We did use glue but you don't really need to. Neat stuff.

Cool. I've also built a bar stool with green wood but it's a fairly crude shop stool rather than a fine chair.

A green wood specialty in my neck of the woods is sauna ladles (used for throwing water). You can buy wooden ones but they are made from seasoned lumber with CNC machines and don't survive more than a year before they crack. The one I made from green wood is still going strong after 7 years in extreme humidity and temperature environment.

It's absolutely routine for hobby and artisan turners and carvers, though. In between the first turn and the second turn, you can air dry, kiln dry, and other techniques. With air drying, you actually want to slow the drying so that it happens more evenly. Otherwise, the outside of a vessel dries faster than the inside, which splits the wood. In general, packing a vessel inside and out with wood shavings helps even the process.

I've also had great results using silica gel on smaller items, although it can be hard to scale it to larger vessels. Much faster drying than air alone, with greatly reduced distortion and cracking.

Reply on news.ycombinator.com