BCMW CPM Rex121 Neck Knife

[BluntCut MetalWorks]

This coming weekend, I will experiment with an additional ht step (if worked, ht version will increment to 2.5), a small rex121 bar is on order. I need to cover cost of materials, so letting goes my reference rex121 knife - *SOLD* asking $138 shipped (international add freight fee).

* To buy: post "I'll take it" and pm or email me your paypal account to receive an invoice from me bcmw at flexbiz com (which also is my email addr)
* Unconditional warranty: return it within 45 days for a full refund

CPM Rex121, 0.138" thick, 0.75" wide, 2.5" blade, 6.75" OAL
Hollow ground, 3.2 oz with sheath
Hardness: 70-72rc
Sharpened: ~30 degrees inclusive, ~0.005" behind edge thick

This knife in tests

 

[Armidabo]

Pardon an amateur, but I thought that the Rockwell scale ended around 70 or so. How do you manage to ensure that the blade isn't brittle?

 

[ice-pic]

I will take it sir..

 

[BluntCut MetalWorks]

Rockwell C-Scale (rc) tester can reliably measure hardness up to 80rc, keep in mind scale becoming more non-linear as hardness increase starting around 60.

Going back pre 2015 - you probably can dig up some of my posts bashed rex121 as poor fit for using as a blade steel. Once I realized rex121 brittle blade is inherent product of std/conventional ht. This blade have been re-hted a few times, the last time was BCMW HT 1.5x. 1.5x is special & expensive because lengthy complex thermal sequencing ht - there are details in CWF thread about Gradienting and Elem partition of 1.5. Effectively this blade is no longer support another re-ht, otherwise if force re-ht it would result in poor (to lousy) blade.

Key objective of BCMW HT 2.5 (without gradient and partition) is to gather improvement on additional ht step. Much easier to observe such by using very high carbide volumes such as: rex121, 15v, s125v. Hope for a bonus = the resulting test blades will be close or as good as ht 1.5x w/o the horrendous complex thermal sequences above 2150F.

Pardon an amateur, but I thought that the Rockwell scale ended around 70 or so. How do you manage to ensure that the blade isn't brittle?

 

[BluntCut MetalWorks]

Thanks for taking the Rex, ice-pic!

I will take it sir..

 

[tinfoil hat timmy]

Good luck with your test!

 

[BluntCut MetalWorks]

Thanks Timmy. HT 2.5 isn't destructive so if it doesn't worked for rex121, I can re-ht with version 2.4 + gradient at sometime later on. Well, Rex bar won't arrives until Monday, so I will toss blanks around to find a s90v subst

Good luck with your test!