Hi Guys,
I wish I'd seen this thread earlier. When I was first brought into the WWIII handle project, I was somewhat concerned about the difficulties I might encounter in drilling tangs on pre-hardened blades. I bought some cobalt drills, which I have not had to use. The tangs are soft enough to drill with TiN coated HS steel drills.
On that basis, the numbers quoted for the spine hardness aren't too surprising, although I'm also unsure how they manage to keep them that low while still maintaining good hardness at the blade edge. I'm also curious about what it takes to prevent the rather thin section of the tang from getting much harder. I assume it must be well insulated when they heat the blade.
I'll speculate as to why the tang (and spine) are left that soft. In addition to the bend vs. break, deform vs. chip considerations discussed above, I think that twisting the tangs (and maybe the spines also) to straighten them may be a planned-for part of the production process before they attach the handles. This statement is not ment to show any dis-respect for the quality of the finished product or the process itself. Quite the opposite actually. Anyone who has had a blade warp after heat treat has probably wished that he had a softer area to tweak when he tries to straighten the blade. From a production sense, this is controlling the things you can, and making sure that the things you can't control don't bite you. Very good manufacturing engineering.
This is pure speculation on my part of course. It does explain some of what I have observed on the WWIII blades.
BTW. On the subject of the WWIII's, things are going well. Expect a progress report on batch 3 early next week.
Thanks,
Bob Couture
No, actually I think he's the guy who builds those high-speed burgler alarms - no, wait, that's Honeywell.