Having all the go no go gauges & the knowledge & specs to use them is a good start, but a Rockwell hardness tester fills in a lot of blanks. Simply spending big bucks on big names is putting a lot of faith in a name.
Isn't it?
There are drawings available that will give you are the pertinent dimensions on the bolt & you can measure most of those w/o the go /no-go gauges.
As for hardness, most parts that are hardened like the bolt are case hardened, not full through hardened, so to know if the case depth is correct & at the right hardness at a given depth, you need to be able to cross section parts & check the hardness across the case.
MPI & HP tests are simply fail / pass tests.............I'm not really fond of seeing bolts I'm going to actually use be HP tested as it can weaken the bolt by subjecting it to abnormally high pressure..............OK as a spot / lot sample test, but I'd prefer my bolts not be HP tested.
Shot peening adds fatigue strength & helps prolong life due to breakage.
JMHO, other have differing views, I am sure.
As for who to buy from, just be careful & go with suppliers that have consistently good feedback from various sources & recognized names.
Certain parts are more critical than others.
No one wants to over pay but sometimes you get what you pay for.............or not.
I think TWR said it best "if it seems too good to be true, it likely is" or something to that effect.
Buy once, cry once.
MM
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