27-03-2011, 05:54 PM
John, as requested, I've attached a pic taken from above the little finial box, showing that the top was cut from the same piece of timber as the base so as to match up the spalting. It's fairly tricky to do because you can't turn a chucking point on the top piece or timber would be lost and the grain wouldn't match up. You have to turn a rebate on the top piece and make it a tight fit into the bottom piece, then mount the bottom piece on the lathe so as to be able to finish turning the top piece. In effect, the bottom piece becomes what is known as a 'jam chuck'. The trick is to not make the fit too tight that it can't be removed, or too loose so that it comes flying off, though it can be held at the tailstock end, by a revolving live centre.
Sorry if that sound tedious and boring!
The trick with woodturning is that the end result leaves other woodturners puzzled as to how the object was held on the lathe. When people pick up wooden objects in galleries and at craft fairs to look underneath, its usually to see how much the item is. When woodturners do that, it's to see how it was chucked in the lathe, and finished off. The other thing about turning bowls is that it's difficult not to end up with either a dimple or a pip in the centre, and woodturners always have an irresistable urge to run a finger over the centre inside to check for a pip or dimple!
Finally, the aim is to get a good a finish 'off the tool' to minimise sanding - the aim being to 'sand the shape of the wood' - not to 'sand the wood to shape'.
Thanks Colin for posting the pic of the little London Plane bowl I turned for you and Bron, and for your very kind comments. I think the timber is quite attractive, with its distinctive 'lacewood' figuring, but the trees themselves can look a bit knobbly and ugly. They're not a native of the UK - they're a hybrid that occured accidentally when two different types of plane were planted in close proximity (in Spain I think, hundreds of years ago) and cross pollinated.
They're remarkable trees, much favoured in urban environments in streets and parks because thay have the capacity to tolerate and absorb pollution, and shed this in their bark, large flakes of which fall off naturally. They absorb large amounts of carbon dioxide and give off large quantities of oxygen, which is why they're often referred to as 'the lungs of London' where they first appeared in the late 1500s. (Some of the trees in London Parks are as much as 300 years old).
They also tolerate root compaction caused by heavy traffic, pavements etc. They're often 'pollarded' - that is most of the twigs and branches are pruned, leaving the tree looking bald, but vigoruous new growth then occurs whih needs pruning a year os so later. The large leaves don't compost down very quickly, so mountains of leaves pile up in the streets and have ot be cleared.
In London, new trees are propagated from basal shoots taken from the bottom of trees, which root readily, so if say an old tree in Berkeley Square needs to be felled, the one that replaces it will have excatly the same DNA.
They're used in major cities the world over - not just in London.
They're used extensively in France - the leaf canopy providing lots of shade, and they look very attractive when they go on for miles either side of the roads, with the sun dappling through the trees.
Hope these ramblings are of interest.
David
Sorry if that sound tedious and boring!
The trick with woodturning is that the end result leaves other woodturners puzzled as to how the object was held on the lathe. When people pick up wooden objects in galleries and at craft fairs to look underneath, its usually to see how much the item is. When woodturners do that, it's to see how it was chucked in the lathe, and finished off. The other thing about turning bowls is that it's difficult not to end up with either a dimple or a pip in the centre, and woodturners always have an irresistable urge to run a finger over the centre inside to check for a pip or dimple!
Finally, the aim is to get a good a finish 'off the tool' to minimise sanding - the aim being to 'sand the shape of the wood' - not to 'sand the wood to shape'.
Thanks Colin for posting the pic of the little London Plane bowl I turned for you and Bron, and for your very kind comments. I think the timber is quite attractive, with its distinctive 'lacewood' figuring, but the trees themselves can look a bit knobbly and ugly. They're not a native of the UK - they're a hybrid that occured accidentally when two different types of plane were planted in close proximity (in Spain I think, hundreds of years ago) and cross pollinated.
They're remarkable trees, much favoured in urban environments in streets and parks because thay have the capacity to tolerate and absorb pollution, and shed this in their bark, large flakes of which fall off naturally. They absorb large amounts of carbon dioxide and give off large quantities of oxygen, which is why they're often referred to as 'the lungs of London' where they first appeared in the late 1500s. (Some of the trees in London Parks are as much as 300 years old).
They also tolerate root compaction caused by heavy traffic, pavements etc. They're often 'pollarded' - that is most of the twigs and branches are pruned, leaving the tree looking bald, but vigoruous new growth then occurs whih needs pruning a year os so later. The large leaves don't compost down very quickly, so mountains of leaves pile up in the streets and have ot be cleared.
In London, new trees are propagated from basal shoots taken from the bottom of trees, which root readily, so if say an old tree in Berkeley Square needs to be felled, the one that replaces it will have excatly the same DNA.
They're used in major cities the world over - not just in London.
They're used extensively in France - the leaf canopy providing lots of shade, and they look very attractive when they go on for miles either side of the roads, with the sun dappling through the trees.
Hope these ramblings are of interest.
David
