Got two 1.25" dia tie rods from work thinking they would be tough and make good drifts.....anyone know what kind of steel they might be and thoughts on tempering...thx, Keith

It's likely spring steel, should make a fine drifts or some PH tools. Cut off a small piece and try hardening it, first air, then oil, then water.........

I would think that 4140 is the most likely but I have nothing more specific than that it is an alloy that is very common in the auto industry and would seem appropriate for such parts.

I believe a lot of folks make their drifts out of mild steel. While I haven't I'd have to say as long as it's very smooth, you shouldn't be waisting your time. I have a hard time being certain of spark test, though it usually gives me an idea. Like Macbruce suggested I'd cut off a wafer heat it up to non magnetic and toss it in a bucket of cool water. Forget it for a few, and when you check on it, it'll be either intact, cracked or in a few pieces. That should tell you where to go from there. Just my two cents, I'm probably lazier than Macbruce :P

I generally pick up bull pins at the fleamarket for my drifts when I can find them for only a couple of bucks.