Any fiishes more durable than the cold black oxide for bolts?

[ng8264723]

I have a bunch of bolts to do all steel. I don't care about color but want a duarble finish. I've heard the black oxide (cold process) rubs off. Any other suggestions?

[erckgillis]

Won't rub off if done right. It's a chemical process and the sealer penetrates the metal. "Parkerized" hot process Black Oxide have lasted for generations.

The cold caswell is easier and safer but the base allows have different "openings" and pores for this treatment. See my post on BO ...

If heat and lubridity are required consider Boron Nitride or TiN depending on cost. The Black Oxide is Great as it adds less than a Micron to dimensional thisknesses for close tolerances. Where plating and spray on coating can effect threads and seating clearances.

Ed