Cleave

9 May

In traditional cabinet making, timbers are ‘ripped’ along the grain with special saws which have chisel shaped teeth designed to carve out a narrow channel or ‘kerf’ to produce straight planks or boards. In order to achieve this and be sure of a stable board which will not warp or distort with shrinkage the wood must be dry.

There is a way to produce long wooden struts or laths without sawing using green wood.

To cleave, to rive, to halve – all describe the act of reducing timber by splitting it along the natural grain.

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This oak frame is made from pieces of oak which have been shaped from the original oak tree by cleaving. It is the foundation of a garden gate I am making for a client. The top piece retains it’s natural curvature having been cleft from a side branch. All of the pieces were split out of a larger oak beam (about 12 inches in diameter) using steel wedges, an axe and a fro, like this;

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Here the felled trunk is being cleft by a combination of steel and wooden wedges and a big, home made wooden hammer, or mell. Once the beam has been quartered, then thinner, relatively straight pieces of oak can be divided further from these billets using a fro. As in ‘too and fro’

Image This is a fro – the blade faces downwards and the wooden handle provides leverage as the billet is being split. Knocking the blade into the end grain and wiggling the wooden handle ‘too and fro‘ opens up the split. The direction of the split can be controlled by applying pressure either side of the beam using a cleaving ‘brake’ – which is a kind of temporary clamp.

Pieces can then be shaped using a side axe on a wooden block:

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or using a draw knife or spoke shave.

The resulting pieces tend to hold their shape over time and retain a great deal more strength because the internal structure of the wood has not been compromised by sawing ‘against the grain’. Unlike sawn timber, which warps when exposed to the elements.

To ‘cleave’ also means to ‘remain true’, or to ‘adhere to’. So, if you want a gate to remain steadfast against the elements for years without the need for preservatives or maintenance, use cleft green oak and a bit of elbow grease.

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