Black Locust Crotch and the Sumitsubo

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No, Black Locust Crotch is not some terrible venereal disease.

You may have dreams of lumber like the picture above.

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But not have access to a $25,000 Woodmizer bandsaw mill. Pretty sweet machine though. Mark and I recently traveled several hours north to a place outside the town of Derby Line, VT, right on the border with Canada, to buy some white cedar. This is the guy’s saw mill.

All shed dried lumber, White Ash, lots of different Pine, and the fragrant aroma of air dried White Cedar drifting in the air. Dreamy, no?

It was the kind of place with such heavy tree cover that the road in was a skating ring of ice that not even studded snow tires could cope up the last hill. We walked in and had the proprietor give a helpful tow.

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Back at Mark’s place I’ve had the time to lash together a new kobiki sawing frame from Black Locust poles I felled and bucked by hand with my madonoko. It was the first time I’ve had a tree barber chair on me from a poorly cut hinge notch and too slow of cutting through from the other side. If you’ve ever seen video of guys felling a tree with a two man cross cut saw and wondered why they’re sawing like the devils in them, its to avoid just such an occurrence. The hinge needs to be a certain width to break cleanly before the tree starts falling. Best to start learning this stuff on small trees.

This Locust wood is mostly in the open, which means a lower branching habit and not a lot of clear boules for typical board lumber. What is there is crotch wood, the kind of stuff Nakashima spoke so eloquently of and used to good effect in writing “The Soul of a Tree”.

And its the kind of stuff that I imagine lots of woodworkers happen upon and wonder how the hell to get it sawn into usable boards.

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Here’s a small piece with the bark off, and I’m trimming the ends flush so that a level can be laid across. The blocks I’m working on are oak offcuts from the ‘free’ bin of Vermont Timberworks.

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Starting with a plumb line on one face I measured out the thickness for the slabs to be taken off, in this case a 4/4 board in the middle to box in a heart check from the pith on the other end and two healthy thick slabs on either side.

You’ll notice that my boards are off center from the pith on the crotch side. While this means I’ll have a crossing pith on the inside face of my slabs it will also produce some interesting figure to the run of the grain.

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With my layout done on either end and small notches cut on the edge of the ends with a pocket knife to register the string the ink line is used to snap straight marks on the convoluted surface of the log. One problem that arises is snapping a line into a deep hollow, the bounce of the string only gives you so much, and the farther back you pull the string to pluck it the more likely you are to pull to one side and produce a curve.

By stretching the string between the two ends you can use a level to drop a mark into the hollow and then snap from either end to that point. Presto, a straight line! I’ve seen this technique used to locate the mortises on koyabari for the posts that support the purlins on a Japanese roof.

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Hang in there sumitsubo!

 

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Very satisfying and rich, the dark marks from sumi ink.

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Its helpful to understand the limits of what the ink line can do. A beautiful little protrusion like this is tempting to shave off, because I know I can get a good line. In this case I could extend vertical batens from my marks on the end grain and again drop a level into the hollows either side, but there’s enough of a mark that I simply sight down along the line and trace in with the sumisashi.

Ready for happy sawing!