Archive | October, 2013

Cherry

13 Oct

I found a beautiful piece of American Cherry at John Boddy’s Timber in Boroughbridge Yorkshire. Thanks to the knowledge of Arty, who works there, we winkled out a 21 inch wide, 1.8 inch thick by 14 foot long slab of perfectly straight cherry. I am using part of it to make a dished seat for a shoe cabinet.

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The trick is to scoop out the central area of the board by running it carefully across the face of a bench saw. The circular profile of a 12 inch radius blade is perfect for carving out shallow trenches along the length of the board to rough out a nice hollow for a seat. The idea then is to refine the dished profile by carving with a decent sized gouge, like these lovely Stubai chisels. By working on the raised timber profiles left in the wood you can gradually smooth out a shallow concavity.

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Here the end grain of the board is shown with the dish profile clearly seen in cross section. A soft abrasive pad on a circular sander takes all remaining blemishes from the profile and leaves a lovely smooth seat – perfect for any backside.

This kind of carving also has the effect of enhancing the figuring in the board…

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All I have to do now is wait for the glue to set on the seat racks to complete the piece. The carcass is built from oak and elm wood to resist rotting, and all the laths are made from cedar of Lebanon to counteract the stinky boots, trainers and sports footwear which will be tidied away in it.

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Autumn weather may have descended in dreary grey clouds, but working on this warm, pink slab of american cherry in my workshop has filled my head with colour. I am anticipating the pleasure of a valued client when I deliver his cherry red, burnished seat-cum-shoe store to him.

Ryoba

12 Oct

This  Japanese carpentry saw, or Ryoba, is a superb tool for cutting accurate tenons.

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One side of the saw is a ripping blade designed to cut along the grain. The other side has a cross cut profile designed to cut through the wood fibres.
Unlike western saws this tool cuts on the ‘pull’ rather than the ‘push’ (like a conventional tenon saw).
The other superb feature of Japanese saws is they are so incredibly thin that they leave virtually no kerf. A kerf is the slot left by a saw blade tearing out fibres – chain saws leave a big (3-6mm) kerf.
Minimal kerf makes marking up the mortice (the slot which the tenon fits in) incredibly easy.

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Here is the finished tenon. I had to make 12 of these in one go for a complicated cabinet, so the little saw made all 12 x 8 = 96 cuts a breeze!

Japanese cabinet makers are very concerned with the balance of their hand tools and the precision of their work. I may not be Japanese, but I honour this sensibility when I make in wood.

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Lignin

7 Oct

Ash

Ash is one of my favourite hardwoods for making furniture. Light and strong, tight grained and easy to work, it accepts precise joints – like the dovetail in this little cradle made from olive ripple ash (Professional photographer Alan Howden has taken all the photographs in this blog). Our beautiful ash trees are under threat however, from a fungus called Chalara fraxinea. First spotted in Europe it has devastated 60 to 90% of Denmark’s ash trees. Whenever I use it now I am conscious of the changing status of our woodlands.

The term ‘olive ash’ refers to the distinctive stripy figuring found in older ash trees resembling the spectacular grain found in Zebra wood or Zebrano:

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This piece forms the top of a lovely long coffee table I made for a friend

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I am endlessly fascinated by the possibilities of revealing the best in timber, decades of growth, peculiarities of climate and the biology of lignification. The latter process – laying down the thick protective walls in the tree’s plant cells throughout its roots, stem and branches – is thought to be the primary way in which these long lived plants protect themselves against the main pathogens which attack them – fungi. Lignin is a truly spectacularly beautiful polymer made from phenolic (aromatic hydrocarbon) residues with the fearsome chemical formula – C9H10O2, C10H12O3, C11H14O4 n

Lignin plays a vital role in conveying water up from the tree roots via the sap wood to the crown of the tree. If you cut a tree in the spring it will literally bleed with water (sap) flowing up from the roots under the tremendous capillary pressure of the lignin impregnated water tubes – the Xylem – in the sap wood.

In most timbers the sap wood is paler and can be found directly under the bark surrounding a core of darker heart wood.

The cradle shows heart and sap wood:

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In the ash tree the olive coloured heart wood is completely blocked and will not convey water, but the paler sap wood is the principle water highway of the plant. Chalara fraxinea grows within the water tubes of the ash tree to block water flowing to the leaves, which is why the tree ‘dies back’ as the common name of the disease – ash die back – implies. The leaves blacken from the extremities and drop off prematurely. In a way, this fungus exploits the very defence mechanism of the tree (the tubes lined with fungus blocking and strengthening lignin) by blocking the irrigation system with its tiny invasive threads, or hyphae.

The Forestry Commission are doing their best to report and mitigate the spread of Chalara nationally and we can be on the lookout for symptoms in our native ash trees on our walks through native woodland. A useful source of advice can be found on the Forestry Commission’s web site.

In the mean time I will continue to seek sustainably sourced timber and work with it in such a way as to respect and reveal it’s deep underlying structure.

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