46 CFR § 56.75-10
Joint clearance
April 15, 2021
(a) The clearance between surfaces to be joined shall be no larger than is necessary to insure complete capillary distribution of the filler metal; between 0.002-inch minimum and 0.006-inch maximum.
(b) [Reserved]
[CGFR 68-82, 33 FR 18843, Dec. 18, 1968, as amended by USCG-2003-16630, 73 FR 65184, Oct. 31, 2008]