Sep 2002 Demonstration - by Peter Mulvaney.

The choice for this demonstration was a pedestal clock in one piece . Normally this type of clock would have the pedestal turned separately and glued to head or top, but Peter chose to demonstrate this more advanced method. Since this would require some turning with an out of balance load, and bearing wear and the resultant bearing play would increase vibration, Peter showed how end and side play in headstock and live centre is checked and advised that while such play can be a safety hazard, accuracy is always adversely affected and such bearings should be changed. At this point our Chairman held up a tube of cream got from his optician, ANTI-FOG, to prevent spectacles misting when used with dust masks, a problem not unknown to many of us. (Who can remember the container of anti-dim .which was included in the haversack with the respirator (gas mask) those years ago?)

Back to the demonstration. A 3inch square by 7inches long approx. of elm was mounted in his 4 jaw chuck using 3 jaws only,( see sketch) which was checked and double checked for security ,and accurate positioning by jaw adjustment. With lathe set at lowest speed, Peter ensured no one was in the firing line of this potential projectile before switching on. When satisfied that all was in order, the recess for the clock insert was formed with a D tool frequently checking to ensure a correct fit for the insert and with a clearance at its rear.

With recess completed, the elm was removed from chuck and mounted between centres, a stubcentre being used for driving. The mount position was not central but in a position calculated so that when turning the spherical head shape of the area around the clock face remained flat. Shaping then commenced, corners removed and square section partly rounded, the position where pedestal joined the head marked with parting tool, pedestal then shaped, initally with roughing gouge and finally with the skew. The spherical top was then shaped down to the small drive spigot, the 3/8in. gouge doing most of the work; and final shaping done with Peter’s home made tool, a sharpened 2in. pipe on a small handle, rapidly achieving the desired shape. With shaping, sanding and finish completed , the spigot was carefully removed with the pedestal held in the chucks nylon jaws. The finish after sanding was cellulose sanding sealer and Briwax, after burnishing with the backside of the clothbacked abrasive.

Congratulations to Peter and our sincere thanks for a splendid demonstration, with the all important safety advice and description of each step of the work as the turning progressed, all of it well planned, entertaining and informative, that made the morning fly all too quickly.

Michael Forde