Unless your thinking of machining long shafts / threads then I would start off with a fixed steady… did you not get a pair of steadies with your Unimat when you bought it, or were they 'optional extras'?

George

In my view NB – the fixed steady is probably the most useful of the two generally – especially if you have a smaller lathe – as it lets you work outsized material that you cannot pass through the mandrel and that cannot be supported by the tailstock centre for whatever reason. I use mine on the S7 very occasionally

Having said that – you've mentioned screw cutting and the moving steady would be very useful if you needed to machine longer, thinner screw cut work (if that's what you are intending?). I purchased one for my S7 some years ago – discovered it was c*** in terms of fit but have never had the need to sort the problem out (so far). I have used a combined guide and tool holder (Chronos used to sell them) to turn some thinner work which has been more useful for the kind of stuff I generally do.

So I guess the best answer is it depends on the type of work you are most likely to do and also to some extent on the size of lathe you have. I'm not sure either would be very high up my list of essentials (I love ER collects for instance!)

Regards,

IanT