13 mm thread? 13 mm thread? bear9298 (Aerospace) (OP) 15 Feb 17 20:29 Question.. Has anyone ran across a 13mm Thread.. looking for the data if so. Thanks in advance. RE: 13 mm thread? KENAT (Mechanical) 15 Feb 17 21:03 My guess would be it's a 'special' in the way you get UNS threads of non standard diameters etc. A cursory glance at ASME B1.13M-2201 the US Metric Screw Thread spec seems to back this up as it isn't in the standard look up tables. Closer examination section 7.6 applies "Designation of Special Threads" with wording reminiscent of the section on UNS threads in B1.1. Quote (ASME B1.13M-2201 Section 7.6 Designation of Special threads) Special diameter-pitch threads, developed in accordance with this Standard, shall be identified by the letters SPL following the tolerance class. Below the designation shall be specified the limits of size for major diameter, pitch diameter, and minor diameter. To calculate the tolerances etc. see section 9 of above standard. My guess is taps & dies may be moderately available for some 13 mm threads to support replacing 1/2" threaded items but I could be wrong. Posting guidelines FAQ731-376: Eng-Tips.com Forum Policies http://eng-tips.com/market.cfm? (probably not aimed specifically at you) What is Engineering anyway: FAQ1088-1484: In layman terms, what is "engineering"? RE: 13 mm thread? MintJulep (Mechanical) 15 Feb 17 21:08 Not a preferred size. But the standards should define what it would be. http://www.iso.org/iso/fasteners_vol1_toc.pdf RE: 13 mm thread? berkshire (Aeronautics) 15 Feb 17 21:23 There is an M13 X1.5 thread standard for threaded repair inserts (Threadserts), and an M13 standard for bubble flare nuts for Hydraulic tubing. What is your end use. B.E. You are judged not by what you know, but by what you can do. RE: 13 mm thread? tbuelna (Aerospace) 16 Feb 17 01:51 My copy of ASME B1.21M-1997 (MJ thread forms) does not list 13mm threads in the standard series tables as either 1st or 2nd choice. But section 6.6 provides guidance, similar to that noted by KENAT above, for designation of special series "MJS" threads having a non-standard diameter such as 13mm. RE: 13 mm thread? bear9298 (Aerospace) (OP) 16 Feb 17 14:37 Thanks Guys for the information.. This is what I need.. Have an awesome weekend all.. RE: 13 mm thread? mfgenggear (Aerospace) 16 Feb 17 15:33 just bear in mind, special go & no go gages will have to be fabricates, as well as special type of cutting tools. you did not explain if these are internal or external or both. external can be single point or thread ground, internal will have to be tapped. and depending on the the tolerance. a better explanation can be achieved if more information is given. RE: 13 mm thread? benta (Electrical) 18 Feb 17 19:25 13 mm makes me think of 1/4" BSP. RE: 13 mm thread? JStephen (Mechanical) 24 Feb 17 05:41 Make sure it's not just somebody's metric conversion of 1/2".