Re-hardened inexpensive chisels vs "good" chisels

[John C Cox]

I wanted to circle back around to this thread a year later with some things I have learned...

1. The Buck Bro's chisels I rehardened were all very chippy after this. Even when I tempered them back softer.. I have been unhappy with their performance - as sections of the edge can flake right off.... Compare this to ONE single Buck Bro's new chisel I received which was very very hard out of the pack (I estimate in the Rc 62 range vs their typical at Rc56 range). That hard factory chisel is quite hard but very tough and holds up well on the wood without chipping. Since this road leads nowhere for me - I am done fooling with these for now....

2. I finally figured out that the Cheap Chinese "Chrome Vanadium" Harbor Freight chisels problems are because of being extremely shallow hardening even though the carbon content appears to be there... A typical brine quench of a cup of salt in about a gallon of water (give or take) only fully hardens them around 1/32" deep... This is a problem because they run almost 1/4" thick... Of course the obvious consequence is that a good round of prep to get them ready can burn right through the hard layer into mush.... And that's how I figured it out.. I ground some warp out and hit mush...

Onwards and upwards... Next item of business - can I figure out how to get them to harden more deeply....

This may point to some of what George was getting at but never said outright... Heating up a little past non-magnetic and quenching to reset the heat treatment assumes they were properly heat treated in the first place... And if they simply started with a fully annealed/spherodized structure with no normalization, induction heat, and spray quench... They may not have gotten the crystal structure into the right form to take hardening properly.... Thus their strange behavior...