Friday 3 August 2018

Boxing the heart

Last week I was down on the Costa na Déise aka The Copper Coast with my chain-saw to tidy up some of the lumber-piles from the DarwinDay Storm of 2014. There are still tonnes of unprocessed and part-processed logs about the place and every storm brings down more fresher, damper branches. It was low tide when I arrived so I went round the headland East of Eden ; Java Bunmahon looking for fish-boxes before I started the chain-saw <brrm BRRRRM>. All I found was a sand-blasted 4m length of 4"x2" = 100mm x 50mm . I couldn't allow that to be a hazard to shipping when it left on the next spring tide, so I brought it up to the house. It had a terrible twist at one end because 4x2s are milled by the million without a great deal of attention to quality. If it matters then don't get your 4x2s delivered! Some of the batch will be knotty, waney, bendy, warped or shook. Better to go to the yard and pick through the stack, rejecting the obviously defective.

Why was my new board twisted? Because it had been cut from a 'tree' species unknown, age unknown, season unknown but probably pine, spruce or fir. And then thrown in the sea. When boards dry out, maybe especially if kiln-dried to speed things up, the outside sap-wood will dry out at a different speed to the central, harder, more lignified heart-wood warping results to minimise the tension in the fibres. The knots come, as you know, from the foundation of side-branches sprouting from the main millable trunk. Saw-millers have known this since first a board was cut. They want to get as much usable lumber from each log that passes through their hands. In the old, local, pre-globalisation days, trees would be felled for a particular purpose in mind, cognisant of the fact that when planks, especially sap-wood planks, dry out they will have a strong tendency to straighten the rings. Amongst much else that means that floor boards have a natural up-side and a under-side. If you nail it upside down, the centre will 'sag' edges will finish 'proud' and put splinters in your socks. Hogging planks are fine because the edges sit down. Of course, with such long-established knowledge the language will be weirdly medieval.
The diagram of various cuts is lifted from a super-wonderful page on how to mill a log so that it is fir (sic) for purpose. Obviously if you need a mighty timber to support an upstairs or a fire place then you'll cut a whole piece and use the super-bendy off-cuts somewhere less structurally crucial. And you have to have something to burn in the fireplace too. This all took me back to 1972, when I was wrapping up the school-days under the care and attention of Mr Wilkinson my inspirational biology teacher.  My biology notes accumulated in 4 hard-backed exercise books which I've managed to hold on to. For reasons best know to himself, probably because he was really interested, he spend a couple of lessons talking about forestry, coppicing and timber. That was never going to 'come up' on the exams but it stuck to me anyway.
B for Boxing-the-heart is a compromise, as are all the cuts labelled in the previous picture. The thing about the generic cuts, like 4x2 or 3x2 is that they are good-enough for a wide variety of situations and so long as you keep the timbers dry-enough and airy-enough any old softwood or any old species will do. Even if you make the ceilings 2.4m high because that's half the standard length of sawn timber in the yard, you'll still have off-cuts and you can usually arrange it to discard the cruddy end of some of the timber.

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