Size:
When you see a lathe branded as, for example, 4" x 24" what does this mean?
The "English" method of sizing a lathe is to quote the centre height - or "throw" - the distance from the centre of the chuck to the nearest point on the bed. In this case the centre height is 4" and the distance between centres (the maximum length of material the lathe can accommodate) 24". With a “bigger-and-better” attitude the Americans of course quote the largest diameter of a workpiece that can be turned clear over the bed - termed the "swing" - and so, in the example above, the American sizing would be 8" x 24". Some American makers, South Bend for example, also quoted the bed length as part of the specification; however, this is an irrelevant figure - it neither tells you the longest piece of material that can be turned, nor the length of the lathe. How big to go? Well, bigger is not necessarily better - and moving larger machines can be an expensive proposition. For most home machinists and small repair workshops something between a 3” x 15” and 6” x 30” machine will be ideal. However, whilst the former would be light enough to lift off the bench yourself, the latter would need an engine crane and a trailer to get home.