[daithi]

Hi guys,
I am a complete newbie looking to buy my first machine.
Not even quite sure what i am going to use it for, probably more artictic work than functional. Anyway, my question os this:
I have eyed up a SIEG C3 machine available in the UK from a supplier that will fully prepare the machine for me(for a fee). However, it is available ex stock in Imperial and as back order in Metric.
Now all the talk about these machines and on here is in imperial.
While in Ireland, where i am, it is miles to Tipperary and i am fond of the odd pint, i like to work in metric.

So what are the implications of metric machine ? will it be more difficult to get tools, material etc? Sorry if this a very basic question, and i guess it is aimed at my more experience European machinists rather than USA , where i am sure Imperial is t he way to go?

Thanks for your help guys.
Daithi.

[sansbury]

On a lathe, the implications are (1) that all the dials will be graduated in decimal inches rather than mm, and (2) that the main feed screw will be inch rather than mm pitch, making it better suited to cutting inch than metric pitch threads.

It is possible to turn a metric machine into an imperial one, and vice-versa, by replacing the lead screws and dials.

If you will never cut threads and rarely use a caliper to measure parts, then the difference will be largely meaningless. If you will be trying to turn 18.5mm shafts regularly, then using inch dials will at some point start to really annoy you. If you mount a DRO, then it wouldn't matter either way.

Personally, unless I needed the lathe NOW, I'd wait to get one set up in the measurement system I prefer to work in.

[TroyO]

I'm a newb too, so I may be off in my info, but... I'm pretty sure you can cut metric threads on an SAE lathe and vice versa... but with a slight loss of accuracy.

As an example, I have a 8x14 lathe and with the right gears I can cut metric thread even though it's really a 16 TPI leadscrew.

But, it will be off by some tiny percentage through the length of the the thread, meaning I can get away with an inch or two of metric thread but beyond that, if I were to say thread 100 MM worth and thread into a "proper" 100 MM long nut it may bind up. Or, if it's being used as some kind of lead screw instead of moving 500 MM in 500 revoloutions it may be 499.2 MM instead.

Anyway, thought that may help the confusion... that's (I believe) why Sansbury pointed out that it's "better suited" as opposed to can or can't.

Maybe I was just being dense but when looking at my machine specs I didn't get why folks saw a difference between standard and metric.. it cuts both, right? It says so right there in the manual... LOL. In reality it cuts standard and "Almost metric". (Or, a metric machine cuts metric and "Almost standard".)