I really like your steel blackening stuff. I've use several wipe-on cold blueing products and gotten good results with them, but sometimes it's desirable to immerse a part rather than wipe it. If you dunk a part in the wipe-on stuff, the solution gets contaminated very quickly.

This is a piece of shop-made tooling that I tried the Caswell blackening stuff on. I wanted to blacken rather than plate because I didn't want to alter the dimensions. It's a close replica of a Logan lathe spindle, used to hold lathe chucks on a rotary table. The round part engages the center hole in the rotary with a very close fit. A bolt secures it from beneath the rotary. The color came out very even, nice and dark, and it got right down into the roots of the threads and even into the internal hole. That would be hard to do with the wipe-on stuff!

A guy needed a special M14x1 mm metric bolt for an antique firearm he's restoring. That's an odd size he couldn't find anywhere. I offered to make one for him.

Since it was for a firearm, I thought a black finish would be neat. I used your black oxide finish on it. He was delighted! - Don Foreman

The hex head fits a 16 mm socket. The parts are much blacker than they appear in the photo; so black that detail didn't show so I lightened the photo considerably to show detail.

I used honed HSS toolbits for finish on the work, then a wash in an alkline degreaser and then a dunk in Caswell's Black Oxide. I get consistently and significantly better results with Caswell's blackener than I get with the various soups I've tried from Brownell's (gunsmith supply house) and Birchwood Casey.

Attached are two photos a cylinder for a model radial engine that was coated with your black oxide product. As you can see, the results were fantastic! John A. Collier