Shotgun hammer fabrication question

[dshumburg]

I purchased a "Ranger" Precision Grade 104.3 at a show. It is in 20 ga and I will restock it as a project. After partial disassembly I find that the sear notch in the left hammer has fractured or chipped so that only about a third of the notch is present. I don't think it is safe to hunt as is, since if the remaining part of the notch gives way the gun will fire. I believe this gun was made by Hunter Arms and finding parts is very unlikely.

I can fab a new hammer using the old one as a pattern. However, I'm unsure of the material and heat treating. I could use cold rolled steel and case harden. I could also use a tool steel and then harden and temper. I don't want the new one to fracture. Anyone KNOW what to do here?

DSH

 

[jim in Anchorage]

Years ago I used a plain carbon water quenching flat from Brownell's to replace the trigger sear in my Stevens 311. I made small chisels and used them to experiment with temper temperatures. Finally found a temp that produced a blade that never seemed to get dull no matter what I used it on and never chipped.

Made my sear and it lasted 20+ years.

 

[rcmodel]

I would probably TIG weld the hammer back up, recut the notch, and case harden the result using Kasenet from Brownells or Midway?

http://www.brownells.com/.aspx/pid=7626/Product/KASENIT

rc

 

[dshumburg]

Thanks for the suggestions. I thought of welding up the sear notch and rehardening. It's a thin section from the sear notch to the hammer pivot pin. ... and I don't have a TIG (rats). That's why I'll probably fab a whole new hammer. The water hardening steel would also probably work. I just don't want to take too long figuring out the temper issues.

 

[jim in Anchorage]

Not that hard-I did the tempering in the oven. Again try some scrap pieces first.

 

[Zeke/PA]

If you decide to fabricate a new hammer, I would suggest using a KNOWN tool steel alloy such as O-1, available in most machine shops.
Heat red, oil quench, polish part, de-grease then temper on sheet copper on stove top till part is the color of light straw.

 

[Ole Humpback]

Aermet 340 is another good candidate for this kind of application. 4-5 times stronger than steel, almost as corrosion resistant as 316 Stainless, and from my experience is at least as hard O1 (but that wasn't an aged alloy I machined) and probably even harder than that.

http://www.matweb.com/search/DataSheet.aspx?MatGUID=64583c8ce6724989a11e1ef598d3273d&ckck=1

It was developed for use in the compressor assembly inside fighter-jet engines & landing gear. Benefit of nickel-super alloys is that they get stronger when they get hotter. No heat treating required. Get the peice machined & installed and you should be good to go.

*NOTE*

I've never made a hammer, but have made parts from Aermet where high-impact loading is a concern.

 

[MarkDozier]

use a high carbon steel to make the part. use a torch to heat and oil quenching. 10-30 works good and gives you a better temper then water.