[heckinohio]

about heat treating??? Barry made a longer ejector. Worked like a new watch for about 20 rnds, then it bent. Being salt water hardening drill rod, we straightened it and turned it almost transparent red and dunked it. 20 more perfect rounds and it shattered into three pieces. Too hard.

Must hardened metal always be 'drawn' afterward??? Is there a reasonably sure way/rule of thumb to harden drill rod but not to this point???

 

[sdk1968]

HEckinohio....

how come you didnt OIL dunk it instead??

not that it may make any difference...

 

[KABAR2]

Short answer is yes, tool steels need to be drawn back. the initial quench makes the metal brittle as you found out.
drawing the metal back by polishing and drawing it to a straw color will give it the toughness to do its job.
depending on the metal it may have to be drawn back further to a purple or a blue-black,
there are also different ways of quenching you mentioned a salt water quench there are also oil quenches
and one I use for flat and "V" springs that is a molten lead quench,
if you plan to reproduce a part yourself the best plan is to make two of them,
and expect the first one to break. Also larger items like Knife blades I have made out of 01 tool steel after the quench
I let them set in a oven at 500 degrees and cook, then bring the temperature down and allow to cool
I have made some tough knives this way, almost as hard as a file but not so hard as to snap like a file.

Allen <><

 

[heckinohio]

sdk....this drill rod was specifically instructed to 'salt water' hardening......

Barry has gotten some 4140. We will try that cold turkey and then harden if needed......will make 8 this time, thats how many bolts I currently have.

 

[sdk1968]

ah ok that makes sense then doesnt it?? lol


let me know how it goes for you.