17-06-2011, 06:34 PM
(16-06-2011, 07:40 PM)Yorkie Wrote: Many woodturners use quite small lathes as they only make small items. The factors to consider when thinking of acquiring a lathe are:
1) The diameter over the bed: This diameter is twice the distance from the centre of the chuck to the bed of the lathe and will be described as the 'diameter over the bed, so for example, if the clearance from the chuck centre to bed of the lathe was 125mm, it would be described as 'diameter ove the bed, 300mm'. That would mean that you could turn an object such as a bowl or a platter, with a diameter up to 300mm.
Ooops, my sharp-eyed chum Colin (Retired) has spotted that I'd managed to double up 125mm to 300mm. How dumb is that? It's what used ot be called a 'senior moment' but in these PC times, is known as an 'intellectual interlude'. It amounts to the same thiing, and come under the generic heading of 'losing the plot'. I should of course have written 250mm (near enough 10") rather than 300mm. Colin is far to kind to highlight this error in the full gaze of a forum posting, so I'm engaging in a spot of 'self-flagellation' and highlighting it myself. Stupid Boy!
There are some lathes that have a movable headstock which can be swung out from it's normal position facing the tailstock, and by using what's known as an outrigger, larger diameter objects can be turned that would be possible over the lathe bed. For example, my own lathe has a clearance of 200mm (8") from the centre of the headstock to the bed, so the 'swing over bed' is 400mm (16"), whch mean that with the headstock in he normal position, I could turn an object such as a stool top or small circular table top) of up to 16" diameter. However, by swinging the headstock out, 90 degrees so that it's clear of the bed and the bench, by using an outrigger toolrest, I could turn an object up to 740mm (29").
My Nova lathe model is known as a 1624/44, which means that it has a turning capacity of 16"diameter, and 24" between centres for spindle work, extendable with an extra bed section taking it to 44" between centres.
A good test of the accuracy of a lathe is to put a centre in the headstock and tailstock and bring them together in what's called a 'kiss test'. If the lathe is accurately machined and set uo, the tips of the points should line up exactly, both vertically and horizontally.
I've just read this posting, and find it deadly dull, in fact it would probably bore the boobs off a buffalo at 5000 paces, so, sorry I must apologise for that and desist::D
David
