Club Meeting 16^th March 2011

 

Dave Jenkins introduced our demonstrator, Les Thorne, thanking him for standing in at such short notice.

 Les selected a pedestal bowl form  from a book that he recommends as an excellent source of inspiration, Classic Forms by Stuart E Dyas. He thought that this shape was probably inspired by the Victorian bust stand and is now used by interior designers for different features. As these pieces are usually painted to suit the décor, the wood used is not critical so for this piece Les used a mix of Oak and Elm.

The Base

Work started by mounting the base blank using a screw mount and turning a 4mm deep recess to suit the expanding chuck jaws using a spindle gouge and finishing with a skew used as a scraper. With the blank mounted on the chuck Les explained that the bowl gouge will cut in the direction of the bevel and demonstrated how the tool will travel backwards along the piece if it is presented in the wrong way. Then he showed us how it should be done. There followed a discussion on the "force field" that dominates the area behind the headstock on some lathes. It appears that this field prevents some turners from placing their foot in this area thereby making it more difficult to turn some areas of the blank. When the laughter had died down he continued his discussion on the presentation of the bowl gouge and the effects of too much and too little bevel rub. Too little restricts control of the cutting edge and too much can cause tool bounce as the grain changes from side to end grain as the piece turns. As work continued Les initiated discussion about the turning of beads and coves on the sides of a bowl and how that differs from spindle turning. When turning a cove he went against the grain for the initial shape and finished with lighter cuts with the grain and used a similar principle when turning a bead. When turning bowls there is always a waste area before the outside is shaped, use this to practice on as it will be waste anyway. The base was completed using a bowl gouge to form an ogee shape, drilling a centre hole and forming a flat on the perimeter as a mating surface.

 

The Bowl

As with the base Les started with screw mounting the larger o the two blanks then formed the outside to an ogee to match the base, truing up the perimeter using an underhand cut. This a way of using the hand closest to the tool rest to grip the tool from beneath as it keeps your hand protected by the tool rest. With the chucking recess cut and the mating surface formed as before Les demonstrated a technique using a traditional grind bowl gouge upside down to "plane" the final surface. The piece was then mounted using the recess and a bead formed on the edge of the bowl prior to hollowing. In these cases Les leaves the bead incomplete and pointed then finishes it while sanding as in makes for faster production. We were then shown three different ways of starting the hollowing cut: -

 

1. With bevel rubbing and the flute closed move towards the lathe bringing the cutting edge in to start the cut then slowly open the flute slightly and then follow your shape.
2. With the bevel at 90 deg to the blank and the flute shut push in the tip into the wood and then pulling back on the handle slowly opening the flute and then follow round your shape.
3. Using a parting tool form a groove where you wish to start cutting then return to the bowl gouge and start your cut within the groove.

 

Les showed us how he supports the outside of the bowl with his fingers while turning the inside and explained the it helped to reduce the distortion along with using a small gouge which reduced the pressure exerted. As the end of the hollowing process approached he was left with the familiar central lump which was removed with a traditional grind bowl gouge. This particular gouge had a 60 deg. Grind which meant that the bevel support was such that he could start the cut with the flute at 12 o'clock without getting a dig in. I now need yet another tool in my box - thanks Les. The inside was sanded using both a power sander and an inertia sander. Les's tip for inertia sanders is to ensure that it has ball bearing rather than a bush type bearing as the latter tend to get clogged with sanding dust sticking to any lubricants.

 

The Pedestal

Discussion over a suitable pedestal height showed that for the diameters of the bowl and base anything from 3 of 4 inches to about 2'6" would be ok. There were just 4 important measurements to be considered, the spigot and mating surface diameters at each end. The spindle blank was turned to round and the spigots and mating surface diameters formed and checked for fit. Diameters for the beads and fillets were formed and the coves cut to shape before the beads ware formed and the fillets finished. Les pointed out that at the diameters he was using the tool overhang can become an issue if the tool rest is too long to allow close access to the bottom of the coves.

Les assembled the project to much applause.

Dave Jenkins thanked Les for his excellent, inspiring and highly entertaining demonstration.

It was then down to clearing up and putting away, mainly by the usual few. I know we can't all do it and too many is not practical but some new faces would not go amiss.

I would like to add my personal thanks to Les for an excellent evening.

Article written by Dave Hutchings