18" by 9'6" column
This jewel has maxed out the lathe capabilities. Made from eight 1.5" poplar staves with birdmouth joints. In order to static balance it I have a 2.5 lb weight bolted to the inside of the column. It is running about 800 RPM with very little vibration. The big secret of turning something this size is getting it balanced. I use a 8" four jaw chuck on the headstock end so I can shift the turning to get it balanced before I start turning. To static balance it I released all belt tension and the piece revolves with the heavy end down. I then loosen the high jaw and tighten the low jaw until the piece balances. Neither the lathe or the bed extension are bolted to the floor and the extension only weighs about 200 pounds. A straight column is a lot harder to do than it initially appears. This one is to be painted so it was only sanded to 80 grit but a stain grade one would have to be sanded to at least 120 but usually 220. Consistant diameter is not that critical because if there is 1/4" difference between top and bottom you would not be able to tell. This one has a difference of less than 1/8". The hard part is that you can't feel any low or high spots along the column as you run your hand along it. The first thing someone does is run their hand along the column so it has to feel straight or the effect is totally ruined. Getting it to look straight is fairly easy but the hand can tell differences the eye can't see.
