Hex Bolt Grades: 2, 5, 8 ... Does it matter?

rickoman · Post by **rickoman** » Wed May 09, 2012 8:38 am

Does it matter what Grade bolt is used to construct the KRMx02?

Looking at this supplier there are a number of grades: Grade 2, Grade 5, Grade 8 and Stainless. FMW Fasteners: Hex Bolts

--Rick

Post by **msimpson** » Wed May 09, 2012 7:18 pm

The cheapest. As a matter of fact many I have found that many of the higher grade carriage bolts may give you problems.

For hex bolts its no big deal but when ordering carriage bolts I recomend you get a sample and verify that the neck on the bolts is not too long. These can cause build problems.

rickoman · Post by **rickoman** » Thu May 10, 2012 10:27 am

Do you have a measurement for the carriage bolt neck? A couple of the suppliers I was looking at provide min/max measurements for various dimensions of their hardware. Would be nice to know before I order that they will work or not.

PS Really enjoying the KRMx02 book and the excitement of getting started on my build, thanks!

Post by **msimpson** » Thu May 10, 2012 3:21 pm

.160 or smaller would be perfect. That said, even the bolts I have been using have necks that are slightly thicker. The key is that on cheap pressed bolts the neck ends are slightly rounded. And that allows you to use a bolt with slightly thicker necks.

Ahren from CNCRouterParts.com says that is the problem. The carriage bolts with squared off ends on the neck. The bottom line is to get a couple samples and try them before making a large hardware order.