KeithB
Resident Half Fast Machinist
The OD of 1/8-27 male straight pipe thread ranges from .390 to .397 according to Machinery's Handbook. The OD of 1/8 pipe before cutting tapered pipe threads is .405. I never realized that 27 tpi was that unusual since every piece of equipment I've run for years has it.
I looked in Table 3 Unified Screw Threads in MH and found listings for the following: 1/4-27 UNS, 5/16-27 UNS, 3/8-27 UNS, .390-27 UNS, 7/16-27 UNS, 1/2-27 UNS, 9/16-27 UNS, 5/8-27 UNS, 3/4-27 UNS, 7/8-27 UNS, and 1-27 UNS. I could not find any standard 27 pitch threads larger than 1".
I looked in Table 3 Unified Screw Threads in MH and found listings for the following: 1/4-27 UNS, 5/16-27 UNS, 3/8-27 UNS, .390-27 UNS, 7/16-27 UNS, 1/2-27 UNS, 9/16-27 UNS, 5/8-27 UNS, 3/4-27 UNS, 7/8-27 UNS, and 1-27 UNS. I could not find any standard 27 pitch threads larger than 1".