TForceApprentice,
1st off, Welcome to Stovebolt!
Your truck looks fantastic.
In answer to your question, the following info is from from some research I did awhile back.
The front spindle (aka "steering knuckle") that fits either side of your 1959 3100 is GM# 3709756 (forged piece with casting# 3708831).* See this page
for Part# 3709756 listed on this page about 1/2 way down the top part list)**
* NOTE: In the 1929-54 Catalog, their are a couple different GM#s for earlier versions of the '51-'53 (GM# 3696337) and '54 (GM# 3709756) steering knuckles for those 1/2 ton trucks, but from what I can tell the '51-'53 number was replaced by the GM# 3709756 listed in the 1929-57 Catalog. It is a "possibility" that you may stumble across someone offering one of the early numbered parts. If you do, it would work for your application as well as the newer numbered part GM# 3709756.
** NOTE: In the later 1979 Chevrolet Master Parts & Accessories Catalog, GM# 3709756 is listed for all '51-'59 1/2 ton trucks.
GM# 3709756Hopefully that opens the door to a wider range of vehicles for searching to find a suitable used spindle to replace yours. You may want to consider searching for a complete front axle assembly as more often than not, those are what can be found for sale as folks replace the original straight axle with a more modern front suspension.
If you don't have luck searching locally, you can always post your own ad in our
Truck Parts Wanted forum.
Dan
