What size lathe?

How do I know what size lathe I need?

For example, I've looked at the Simplicity Roller from plastowtractionengines.co.uk and I liked the line "The only machining necessary is to bore and face the hub and turn the O.D edges of the roll." Making me think this might be a suitable model to be that step between full machining required and no machining required.

But how big would the lathe have to be? How would I go about finding out?

I could have 3 inch or 4 1/2 inch, but I currently have no idea what lathe I would need for either of them.

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An experienced modeller and professional machinist once told me 'You can make small things on a big lathe but you can't make big things on a small one'.

I'm guessing that the 4.5 is a Boxford. I have one of these and, although it's a comedown from the 6" I used to have, it does everything I need and is an excellent lathe.

Brian

The rear rolls on the 3" are approx 12.5" and the ones on the 4.5" are approx 19".

It may just be possible to get the 3" ones into the gap of a gap bed lathe but would depend on the width of the gap otherwise you are looking at something with 13" or 330mm swing minimum for the 3" and at least 20" swing for the 4.5" version. I would go for a bit more to avoid having too much tool overhang as the carrage may get in the way even if the lathe bed does not.

An alternative would be to outsource the machining of the biggest items and to the rest yourself.

And yes the quote only applies to the castings for the rolls, all other parts will need to be machined, about 1000-1500hrs work on average for a traction engine.

Edited By JasonB on 11/09/2018 16:15:52

Don't burden yourself with too big a lathe just to machine a couple of items a decade. Check out clubs in your area that might have a workshop and also evening classes in schools and colleges. If you are a beginner it would be better to start off a bit smaller to avoid tying up a lot of money in something you might not like in the end. Also if you look at an engine count the number of round things. Most things are not round so the lathe can end up as the least used tool in your workshop. There are also ways of dong bigger things without a big lathe.

I’m more of a Walt Kowalski man, - every man needs a lathe.

http://www.youtube.com/watch?v=i_if8-CkTZE&list=RDi_if8-CkTZE