OK, I have done some googling, and can't seem to find an answer.

Well, I can, but the price is a bit high. Need to check a few more places to get an idea on what is a good price.

I need to buy some plastic balls, 25mm Dia. Preferably Phenolic or Delrin. Not Nylon, as it absorbs water (these will be submerged)

I have found some, pre-tapped to M6, but they are £2.99 each.

I am happy to drill and tap, but if the difference is only something like 50p per ball then I will just buy the others.

Anybody know of a good engineering suppliers that does this sort of thing. I have looked under machine handles, all sorts of stuff.

I would be wanting about 20 of them.

Thanks in advance

pool or snooker balls - maybe a junior table set to get small enough diameter?

What are you doing with them...?

Amazon in the US sells that kind of thing if you know someone going out in the near future.
http://www.amazon.com/Acetal-Delrin-Polished-Grade-Diameter/dp/B000FN0P7A/ref=sr_1_12?ie=UTF8&s=industrial&qid=1261396553&sr=1-12

Doubt my googling is better than yours, but this place might sell a small order.
http://www.theppb.co.uk/index1.htm

There are some threaded balls if you search the Skiffy plastic parts web site.
Tried to link the page but it went wrong.
Steve

Cheers for the replies guys, have found them at RS Components. 74p each is more like, already threaded

They are for strobe arms for an underwater camera.

Strobe arms.........right!