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4th January – Les Thorne

11 January, 2017

Tonight’s demo was to have been by Bob Hope but Bob had to pull out because of illness. We wish Bob a speedy recovery. Fortunately Les was able to step in at the last minute and gave us a comprehensive demonstration of making a bowl, with some texturing and colouring thrown in for good measure.

Les started by talking about gouges and the confusing way we classify the gouge size in the UK. This is measured from the inside edge of the flute to the tangent on the opposite side of the rod. So a 3/8” gouge is usually about ½” in overall diameter. The Americans take a more simplistic (dare I say logical?) approach and call a gouge by its overall diameter. Les says that unless you are making really big bowls you don’t need anything bigger than 3/8” (UK).  Then there’s the shape of the flute, ranging from a wide U shape to a parabolic shape sometimes called a superflute. Protagonists of each argue their merits on the basis of capacity of the flute to conduct shavings away to rigidity of one with more steel remaining to the versatility of a compound shape to make a variety of cuts. Les likes Sorby gouges though they are the only manufacturer which doesn’t give them to him! However, any gouge from a reliable UK maker is likely to be good and consistent from one to another.

les-types-of-gouge

Then there’s the question of the grind. Les does not usually go in for long ground back wings. Such extreme shapes are good for removing wood rapidly from (wet) logs but can be tricky to use in more normal projects. (Anyone coming to the Phil Irons masterclass may well see an impressive demonstration of a more extreme grind.)  You are unlikely to get away with one shape anyway. As we will see, to rub the bevel on the inside of a bowl at the bottom necessitates a tip ground steeply almost straight across. I’ve included some pictures of Les’ gouges.

Les started turning his bowl with a roughly cylindrical ash blank with grain going across it in the usual way. So the gouge will encounter grain ranging from side to end as the wood rotates. For the purpose of the demo, Les turned the blank into a cylinder. (In practice it would have been quicker to start cutting a bowl shape from the outset). Cuts can be pushed or pulled. Simplistically, push cuts have a rubbing bevel following the cutting edge so are easier to control and give a better finish. Pull cuts can remove wood quicker, particularly with a long grind. Les used both on his cylinder to demonstrate the difference.

les-1-starting-point   les-2-turning-outside

The spigot for the base was cut next, marking the centre for alignment when eventually reversing to finish the foot. The spigot and the rim define the ends of the outside curve which Les proceeded to cut. A push cut is difficult at the spigot end when working over the bed so Les used a combination of pulling to start with transition to a push. This is a situation when a movable headstock makes life easier. Once the shape has been established, some find it helps to refine it by scraping. This can be done with a scraper or the wing of the gouge if ground back enough. A final finishing push cut leaves a smooth surface requiring minimal sanding. As the bowl curved inwards at the rim, the optimum “downhill” cut near the rim needs to be away from the rim towards the widest point. Cutting the outside curve requires the gouge to be slid along the tool rest and the gap between the rest and the surface varies with position. This is a case where a curved rest would help as the gap is more constant.

Les being Les he applied a random texture to the surface at this stage using a hand held mini Arbortech type cutter. The rough surface was smoothed using a rubbing wheel before colouring.

les-3-about-to-texture-bowl   les-4-texturing

Les used Chestnut spirit based dye which is colour fast and, unlike water based dyes, does not raise the grain. The dye was applied via a venturi-fed air brush with the reservoir beneath the nozzle to suck the dye into the air stream. A number of colours were applied and sealed with an acrylic sealer. This was not sanded as to do so would have cut through the thin layer of dye.

les-5-smoothing-textured-surface  les-6-applying-colour

The bowl was then reversed onto the chuck for hollowing using the spigot. Most of the work was done with a ¼” bowl gouge. The gouge should enter the wood with the bevel at right angles to the surface to avoid kick back. This can be difficult to achieve working over the bed. Again, a swivel head stock would make this easier.

As the hollowing progressed Les was asked about inserting the end of the tool rest into the bowl. He said he wouldn’t do that and of course he had a reason. Keeping the rest at the rim allowed the gouge to trace a curve with the rest as a fulcrum using an overhand grip. With the rest in the bowl, whilst the overhang would be less, the gouge would have to be moved along the rest as it cut making it more difficult to achieve a smooth curve. Also you would be working at the end of the rest rather than the more rigid centre. If there is a concern about vibration, use a thicker gouge, say ½”

As the bowl is hollowed, the rim impedes the gouge and it needs to be swapped for one with a steeper grind for the bottom to maintain a rubbing bevel.

les-7-hollowing

Les then power sanded the inside from 120 to 320 grit keeping the disc as flat on the surface as possible to avoid the edge cutting a groove. Having blown the dust off Les then gave the inside a light spray of yellow and added a black shadow to emphasize the undercut rim.

Finally, reversing onto a block faced with thin rubber and supported by the tailstock at the centre point (which had been marked at the start) allowed the foot to be turned away.

les-8-finished-note-arrangement-for-final-reversing

As usual Les’ demo was full of advice about tools, procedures, options and pitfalls delivered with the confidence of one who has learned the hard way and knows what he is talking about. I hope I’ve done it justice.

les-gallery-crit-with-a-graham-barnard-nested-bowl

At the tea break Les did a helpful critique of the few items on the gallery table. I know it’s been Christmas but it would be nice to have some more next time. Pictures of the gallery items are on the website.

Dave Gibbard

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