Quoted from the Gus's sight
Please note that the unused vacuum barb on the solenoid valve is blocked off! I represented the block with a black rectangle. You must cap off this nipple. Again, there is a small (about .020") vent hole drilled into the output barb of the Grainger valve to act as a vent.
Its says about .020 inch hole
1/64 is .015 and 1/32 is .031 will the 1/64th bit work if I egg it out a little bit? Or is my math not correct at converting today. Thanks guys