Does anyone have a manual for something like a Pultra 1750 or 1770 which
might contain this information?
Yes I have a manual and it recommends any of the following oils:
TSD 429 from Shell
High speed spindle oil SO2 from Duckhams
Supramor light spindle oil from Manchester Oil Refinery
Vitrea 13 from Shelmex BP
Velocite oil N.6 from Mobil
Hyspin 40 from Castrol
That's not really very helpful to you because all those brands have long
gone, so let me tell you that I use ISO 32 hydraulic oil in my PR2, just the
same as my Myford, and it works fine.