Doug Turnbull

penguin

Does Turnbull harden the receivers on the restored Winchesters he produces. If so why?

Is it for eye appeal only?

He Dog

Because color case hardening is what he does. He is a very nice guy, why not ask him?

mnrivrat48

Case hardening if I remember correctly is a surface treatment. It hardens only the surface, but not the whole receiver as heat treatment does.

Locust Fork

I've read where the type of treatment Turnbull does uses cyanide. There is a way to do color case treatments at home.....using different charcoal types and heating the metal.
I've always loved the look of anything case color, but I'd be terrified to try any process myself.

allen griggs

Where is this guy located? I know a Doug Turnbull in Atlanta. Unusual name, Brit name.

iceracerx

There is a difference between 'Color Case Hardening' and 'Case hardening' or carburizing.

The 'color' is on the surface while the hardening is to a given (controlled) depth.

The 'color' can wear off, but the part is still 'hardened'.

I had a Stevens Walnut Hill 22lr that only had traces of 'color' left on the receiver. The surface was still hard.

TRAP55

Hard on the outside, softer on the inside, it strengthens the receiver the old school way. Now it's done with just a furnace heat treatment that some say Paul Mauser perfected. Winchester improved on that with the M1917, and later adopted by Springfield and Remington.
The colors come from the recipe of charcoal and bone the receiver is wrapped in, and ultimately, the solution it's quenched in, and how it's quenched.
Handling, sunlight, and time, will fade the colors to a silver patina. Winchester and Marlin both had their own formulas and process, resulting in two very different case colors, and patterns.
Turnbull reproduces the Winchester method. The Marlin process was lost to time. A couple of years ago, a member on the Marlin forums experimented until he got it right. JMO, but the Marlin color case is the prettiest.