I understand it's a given that the hole will stretch after the dimpling operation. The amount it will stretch can be influenced by the die used, starting hole size, and hole prep (over deburring/chamfering too deep).
What I'm having trouble with is understanding how the hole specs come into play here. I would assume the hole tolerance applies regardless if the hole is dimpled or not. Mil-std-403 table I specifically has limits for the hole before and after dimpling. I found some builders calling it good as long as the starting hole was in spec. Other builders apply the limits to the dimpled hole.
I recently dimpled some holes for AD4 rivets in .032 material and the holes came out .140-.143 (checked with gage pins). The starting holes were reamed #30 and measure .129. The deburring/edge breaks were anywhere from clean/sharp to .003 max chamfer.
So I freaked a little and emailed Vans since this was over the high limit of .135 given in MIL-R-47196 which is the spec Vans references. The response was as long as the starting hole was good there is no problem, which is in line with what I found some other builders saying.
I kind of don't like that answer because how should we evaluate if there is a problem. If my holes came out .160 would it still be considered good since the starting hole was good??
What I'm having trouble with is understanding how the hole specs come into play here. I would assume the hole tolerance applies regardless if the hole is dimpled or not. Mil-std-403 table I specifically has limits for the hole before and after dimpling. I found some builders calling it good as long as the starting hole was in spec. Other builders apply the limits to the dimpled hole.
I recently dimpled some holes for AD4 rivets in .032 material and the holes came out .140-.143 (checked with gage pins). The starting holes were reamed #30 and measure .129. The deburring/edge breaks were anywhere from clean/sharp to .003 max chamfer.
So I freaked a little and emailed Vans since this was over the high limit of .135 given in MIL-R-47196 which is the spec Vans references. The response was as long as the starting hole was good there is no problem, which is in line with what I found some other builders saying.
I kind of don't like that answer because how should we evaluate if there is a problem. If my holes came out .160 would it still be considered good since the starting hole was good??