And thank you too :)

I got as far as the calculators and charts at nookindustries.com/Engineering/Calculators.cfm but they hit me with a 'Slender Ratio' (?) error. So, it was either a morning with Wiki or a quick post here and do some work.... But boss, they're ball screws!, heh.

Always a problem buying stuff that needs a couple of quick modifications to match what you're trying to do, in this case if it costs the equivalent of £100 in money and time then I'd be better off buying new. I'll ponder :)

Thanks again guys.