Packard Forum Index » Pre-War (1899-1942)

I was wondering if I should get my snap rings re-chromed or try to find reproduction. Does anyone know of a source for reproduction 20" snap rings? I have disc wheels.

Don't know about reproduction rings, but if you do have them rechromed, don't forget to have them treated to relieve the hydrogen embrittlement that results from chrome plating, or they'll be subject to cracking.

Great information Owen_Dyneto! Thank you!
I had heard that chroming might make the rings brittle, but I didn't know if that was true and I certainly had not heard that there was a "fix"

sydney

I was told that hydrogen embrittlement is not going to affect anything as thick and robust as a snap (lock) ring. If the lock ring cracks, it's because of deeper problem and would have had nothing to do with the plating process.
If you decide to buy a reproduction (Coker has them, or they used to), you will have to have them plated anyway, because they come unplated.

I was told that hydrogen embrittlement is not going to affect anything as thick and robust as a snap (lock) ring.

Possibly so, but I've heard the opposite as well. Would be nice to have some good, authoritative documentation on the subject.

Here is a start:

en.wikipedia.org/wiki/Hydrogen_embrittlement

My brother-in-law is quite informed on metals, and has a metallurgist on staff:

"Iron and low alloy steels are generally not susceptible to hydrogen embrittlement. High (tensile) strength steels can be. However, even with embrittlement, it is relatively easy to bake the parts at 400F after the plating process to remove the hydrogen. So, no matter what the material, if you do it right, you should be okay. Otherwise, it could be a problem with some materials, including the lock rings."

High tensile steels are more susceptible to hydrogen embrittlement. The wheel lockrings are a low carbon steel and in compression when installed on the wheel.

A part in tension is more apt to fail if it has hydrogen embrittlement. The spokes on a wire wheel are subjected to tension and compression, and early chrome plated wire wheels failed due hydrogen embrittlement.

The post plate bake process is the cure for hydrogen embrittlement. Most platers can do this for a minimal charge.

Some additional info:

classicmotorsports.net/articles/wire-wheels-classic-cars/

Here's a contact for Coker that I went through for 19" reproductions.

Jim Hildebrand
VP of Exports


Direct: 423-648-8506
Fax: 423-756-5607
jimh@coker.com

Henry Yeska may have some, but beware as it is not unusual what he sends is incorrect. I always try him, but have always been disappointed with what he sends.

A big thank you to all of you who replied !
It is terrific to find so many people willing to share their expertise.
What a great site !