What size are standard bars & holes?

I'd thought that they were 1" for standard and 2" for oly kit. I've turned up some steel weights to use in my gym at home and the spinlock dumbell handles i have, and my standard ezcurl bar are both 30mm rather than 25.4mm - the oly bars i have are both 50mm dead on.

Obviously if the hole is bigger than the bar then the weight will go on - but the bigger the difference the looser the fit and the more play there is when moving the things around.

If you've got standard kit can you tell me how big the holes in the plates are and how thick the bar is please?

Cheers

These are the four 2 1/4 kg weights i have made and almost finished;







They have simply been turned up from steel discs as shown in the first photo - there are 4 done and i have another 16 discs that i can use. The first photo shows them with 30mm holes drilled & bored out, but then the newer brownish tinted ones have been faced off, given bevelled edges and lightly polished - then tempered in the Aga overnight.

Was aiming for a blue tint but seems that they didn't reach a high enough temperature. Going to lacquer them and hope that's enough to stop or at least minimise any rusting.