Hi Stu,
My Dad is about to launch into making one of your drain valves, why only 1 you ask, well he's fitting it to the steam operated brake cylinder on his loco & there is only 1!
The reason, currently the steam valve acts as both steam to, & HOT condensate from the cylinder, which ends up on his fingers! Told him he needs to harden up a bit, but at 87 he said he was past that!
Anyway the reason for replying is that on printing out the drawings, Thankyou very much for posting, I spotted that you had spec'd 7/32 x 40 ME on the body for the plugs BUT 1/4 x 40 ME on the plugs! I thought you may want to update the drawing so somebody doesn't get caught out.
Thanks again for posting the drawing, hopefully in due course I can report the out come.
Cheers Kerrin