andrewnummelin wrote:My daughter's fiance has asked for advice on getting a lathe for work with various plastics, resins or hard woods
A very simple question, but the answer could take a long time
The problem is that we are talking about a vast range of materials, all with very varying properties. A close grain hardwood timber such as beech will have very different properties from an open grain timber such as chestnut, and the wide range of plastics materials available will all have different properties again.
Winander wrote: I think Terry Bendall in his series on machine tools in the Snooze covered the topic as there is nothing to prevent metal workers using them, in fact jewellers often do.
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Yes I did and it works well for things such as chimneys and domes.
Winander wrote: Wood turners usually work freehand with specialist long handled chisels (that's probably an over-simplification, but a reasonable description) placed on a steady-rest
Yes that is correct but it is possible to buy small wood turning lathes, just as we can buy small metal turning lathes and the tools will be correspondingly smaller. Wood turning is a popular hobby and there are a number of magazines devoted to it and courses that can be attended to learn the basics. One of the best books on woodturning that I have come across is "The Practical Wood Turner" by Frank Pain. This was first published in 1957and I bought my copy in 1965 and it is still available. It is obviously a bit dated in style but still offers very sound advice.
The purist would shudder at the thought of turning wood on a metal turning lathe since the shavings and dust will clog things up and absorb the oil but if you can live with that it can be done. Just provide a tool rest and invest in a set of suitable turning tools. Close grain hardwood timbers can be turned with cutting tools used for metal and a round ended tool will give a fairly good finish. Use glass paper if you must but take the tool right out of the machine and wear a proper dust mask. A proper craftsman (or woman) will keep their tools sharp and finish things from the tool and not use glass paper at all.
Alan Turner wrote:Some plastics require care as if they are turned at too high a speed they can get hot and give off poisonous vapours - which can kill! PTFE being a case in point.
Possibly but unlikely with care.
My advice would be to buy a metal turning lathe and then buy (or make) a suitable rest for the wood turning tools. Most plastics that model makers are likely to use can be treated as metals and turned using the same sort of cutting tools. The best book I have forum on metal turning is The Amateur's Lathe by L H. Sparey, again very old but still available and a very sound source of advice.
And a bit of advanced publicity.... my offer to provide a demonstration at Scalefour North next year on using machines tools in railway modelling has been accepted so come along and ask your questions then.
Perhaps I had better bring my wood turning lathe as well.
Terry Bendall