(01-05-2011, 04:33 PM)Brianc Wrote: That's what I call a beautiful bowl. I can imagine the worry you went through as you turned it. As a matter of interest, how do you finish off the base that was fitted to the faceplate or chuck without damaging the interior of the bowl?
Thanks for your kind words Brian.
It's a good question, because by that final stage, it's possible to wreck the bowl and spoil all the work and effort. I put a piece of kitchen roll or masking tape on the jam chuck. The trick is to not have the bowl so loose that it flies off, and not so tight that it damages the inside or cracks the bowl. Having the toolrest close up to the base when finishing it will obviate the risk of the bowl coming off the chuck.
You always start by turning the outside of the bowl, by mounting the blank on a 'screw-chuck'. The first task when turning the outside is to turn either an internal or external dovetail to fit the bowl onto when turning the inside. I prefer to turn an outide foot for two reasons. Firstly, you can turn a larger foot to minimise the risk of the workpiece from flying off the lathe, and secondly, an internal chucking point means that you have to be very carful when hollowing the bowl out, not to go too deep and go through the foot. When both the outside and inside has been turned and finished, it's neccessary to turn the dovetail off the foot and to neaten the foot, the end result being that it puzzles people as to how the bowl was held on the lathe! I never sell anything I make - it's a hobby - not a vocation, but whenever I see stuff offered for sale at craft fairs, NT shops or wherever, like all woodturners I turn the bowl (or vase or whatever), upside down not to check the price, but to check to see how neatly it's been footed! The other thing woodturners will do is run their finger across the centre of the inside of the bowl or platter, because two failings - apart from scratch marks due to poor sanding - are to either leave a 'dimple', or a 'pip' in the centre. if it's been turned with skill, a finger run across the inside will feel a smooth curve which follows the outside contour.
The other thing that comes with experience, is the abilty to get a good finish straight 'off the tool' to minimise sanding. This is especially important with open grained timbers, which can take an eternity to sand. The aim is to 'sand the shape of the wood' - not to 'sand the wood to shape'!
I don't want to wear out my welcome on the forum by posting rather too much woodturning info, but to illustrate the processes involved and how the timber is mounted on the lathe at various stages from start to finish, I've just turned a little bowl from a scrap of iroko timber. Ive attached a few pics in this post, and will put out a few more in another post. In this post, I've attached pics of the outside, showing how the wood is mounted on a screw chuck to turn the outside, how the dovetail foot is turned so that when the outside has been turned, the bowl can be mouted on dovetail jaws to turn the inside, and I've shown the outside roughed out, then sanded and polished.
Hope it's of interest.
David
