Most decent sized US cities have a fastener wholesaler. In Portland, Maine it is KL Jack
(they ship anywhere)... Fastenal is also a wholesaler of fasteners, we have one here in Poartland, but like Grainger I find their prices offensive, even at the wholesale/trade level.
For example Fastenal was $13.00 more for a box of 100 1/4 X 20 SS nyloc nuts. I pay about $5.50 for the 1/4 X 20 nlylocs at KL Jack
and they'd cost me close to $19.00 at Fastenal... That is a HUGE markup!!! Fastenal I am sure buys at a much better price than KL Jack, but KL Jack does not try and rip me off just because what I buy is stainless steel....
I am at KL Jack about once a week and the guys are GREAT.. They also have the best price in the country for the FTZ battery lug crimp tool..
FTZ Battery Lug Crimp Tool