Does "P;lay with" mean restore, or actuallt use?
How old is "old"?
Drummonds could be over 100 years old, A Myford ML7 could be anything up to 75 years old.
A Myford ML1,2, 3 or 4 will be older than that.
Suitably set up quite useable machines, although, possibly withe exception of the ML7, accessories may be hard to find to equip the machine fully. ML7 geras are almost identical to those on the earlier MLs so can be modified very easily.
The problem might be obtaining Whitworth or BA form hardware. You might find yourself in the "Chicken and egg" situation of needing to get the machine operable to make what is needed!
Capscrews and grubscrews are the most likely to cause a problem. Hexagon nuts, bolts and setscrews should be fairly easy to make.
Some might regard a 20 or 30 year old machine, probably from the Orient, as old, but with so many being badge engineered, spares from other lool alikes, or even later machines, may be available.
Good work can be done on an old machine, once set up and operated, correctly.
OK, they may not be suitable for the high speeds to optimise carbide tips, but HSS is possibly superior to what was available when they first left the factory.
Howard