AERO – Threading Tools For Aerospace Materials
AEROSPACE THREAD NORMS
ISO 3161 / ISO 5855 with radius
The norms ISO 3161, UNJ, and ISO 5855, MJ, refer to the construction of aerospace threads. They define the general dimensions, the tolerances to be used, and the radius requirements for the construction of the profiles.
These norms specify that the radius profile at the external diameter must not be smaller than the basic profile or exceed the permitted external diameter at any point. However, the standards do not specify any particular radius. The construction of our taps is based on the required tolerances UNJ in 3B and MJ in 4H. The designation is subject to a strict rule, according to which the pitch must always be mentioned.
ISO 5855 MJ 6×1 4H5H: Tolerance of the flank ø followed by the tolerance of the internal ø.
ISO 3161 0.2500-20 UNJC: also accepted with UNJC 1/4-20 3B
