j0llycage
Member
As the title suggests, I'm curious about why nearly all 3/8"-16 plug taps are designed with a shank diameter roughly equal to the major thread diameter while the other common SAE taps have a shank diameter closer to the minor thread diameter. I'm familiar with the concepts of through hole and blind hole, but other than the one in my Harbor Freight 60 piece set, every 3/8"-16 I've seen (either in a kit or sold as an individual) has a thicker shank than the 7/16"-14 above it (and sometimes the 1/2"-13 as well). It appears that it's so universal that even the empty Huot tap cases have smaller holes on either either side of the 3/8"-16 slot for the 5/16"-18 and 7/16"-14.
Are 3/8"-16 more likely to snap? Is there an unwritten rule that you never tap a through hole in 3/8"-16? I just find it kind of unusual. The USA made Irwin Hanson is like this, the Japanese made Century drill & Tool, the Austrian Hi-Test... From a design standpoint- with the exception of the micro sizes that need the extra thickness for durability (M2.5, M3.0, #4, #5, etc.)- I would have figured they'd all be one way or the other (major thread diameter shank thickness or minor thread diameter thickness)- or that companies would make all taps in both styles to fit various needs (heavy duty vs economy or precision). Is there a logical explanation?
Are 3/8"-16 more likely to snap? Is there an unwritten rule that you never tap a through hole in 3/8"-16? I just find it kind of unusual. The USA made Irwin Hanson is like this, the Japanese made Century drill & Tool, the Austrian Hi-Test... From a design standpoint- with the exception of the micro sizes that need the extra thickness for durability (M2.5, M3.0, #4, #5, etc.)- I would have figured they'd all be one way or the other (major thread diameter shank thickness or minor thread diameter thickness)- or that companies would make all taps in both styles to fit various needs (heavy duty vs economy or precision). Is there a logical explanation?