I know it doesn't sound very advanced, however it doesn't seem to apply to a specific engine/tech forum. And it is to support my stroker build up , sooooo....

Anyone know if there are Pros/Cons of using a 12-point nut/head with fasteners instead of a 6-side hex nut design?

I'd wager the 12-point shouldn't slip as much due to the smaller angle between nut faces (120* for hex, <90 for 12-point)... does this ensure a more consistant torque value? is there some other advantage to them?

I'm trying to figure out why rod bolts use both... is it really worth the extra 10 bucks for 12-point heads/nuts?

 

in space confined areas its much easier to work with 12points. Think of the amount of radius needed to rotate the distance of one of the six flats on a 6point. With 12 points you can "shorten" the distance and it allows ease of tool interface...{USE}.

I always use 12 points on headers!
12points always use smaller wrench sizes compared to the same thread type on a six point, also a plus

 

while we're on the topic: would going with undercut 12-point heads cause any weakness in a bolt? (in stead of the standard 12-point).

I know people go with an undersized 5/16" head bolt for header bolts due to clearance issues, but strength really isn't much of a issue there. However... is there any strength decrease with undersized heads in general? My understanding is that a stud uses the threads to provide the clamping force, however a bolt uses the bolt head... the undercut size would affect clamping forces in this case right? hmmm...

 

Under cutting removes the radius from the inside of the clamping surface of the fastener. This allows for improved fastener load forces on the thread pitch.