How this is too thin for HT?

DeadFall27

DeadFall27

Joined
May 18, 2011
Messages
1,476
Hey all,

My apologies for the question. Im grinding my first blades and its going....well, not super great, but Im hanging in there. In my attempt to fix my mistakes on the swedge I put on a puukko blade im working on, I got really thin on the spine. For 80CrV2, how thin is too thin to HT?

Im assuming this one will go to the scrap pile thats getting bigger, but I wanted to ask. I have been searching online with no clear answer so far. I have seen most people say grind 70-90% of your knife prior to HT, But I wanted to see if I could squeeze this by. I also read that it can also be dependent on the steel type as well.I have to outsource my heat treatment, so my biggest fear was sending this overseas just to be told they cant do it.

Thank you everyone

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I have HT 1/32" 0.035", O1, at spine with no issues. I did put the blade between weighted aluminum plates or aluminum plates in a vise after quenching to black.
scott
 
It’s not just bacon edge. You can have up to 0.010” decarb after thermal cycling and heat treat. You have to have enough good steel left after cleaning up the decarb.
 
Stacy - I don't see an issue. I regularly HT blades as thin a .04" with full distal taper.

Natlek said:
That was unnecessarily to thick ,15N20, 80CrV2 ,52100 , 1.2519 ,5160 ,1095 I leave 0.020/0.5mm and never have bacon ? edge ........
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You misunderstood my post. I use .040" stock and fully taper it. The steel is left unground on the bevels, which I do after hardening. On blades above .060" I usually take the edge to around .020" before HT ( or grind post HT).
 
Thank you all for your input. I just ruined it on the sander today, so I'm buying a jig...so...it wont be getting treated anyway. I. Going to learn to free hand, but I want to make some designs first. I don't have the play money to burn too much steel. I've ruined 5 blades out of inexperience in 4 days.

I apologise for my questions, I don't want to dilute the shop talk with random questions from a hopeful make andabother anyone. Thank you for dealing with my questions! I hope to make it to a level that you all are able to one day. I try to do my research before asking, bit sometimes don't find what I'm looking for.

Are most steels able to be heat treated to this thin amount without warping? Or just a small amount? I want to make stainless puukkos in the future as well, and do not want to make a mistake just starting out. I would love to try nitro v puukkos in the future.

Wasting money is awful, but as a hobbyist trying to learn the trade, I just want to be careful.

You have all been so kind, thank you for your input and responses! I can't wait to show you my first puukko here in the next month or so! I've done handles in sheaths, but my own steel is foreign to me, so I apologise.

Please have a wonderful day, and I hope you and your families are well!
 
Most steel can be HTed pretty darn thin. Leave at least .020 to .030" at the edge. Immediately after pulling it out of the quench tank, straighten it. It is quite soft and almost rubbery. You have from 10 to 30 seconds to straighten it with gloved hands or hammer it on a wooden board ( use a wooden mallet) . Wood works best because it won't dent the soft austenitic steel as bad as a metal hammer and the anvil … and it won't suck the heat out as fast ( giving you more time to straighten. As the steel reaches 400°F it stars to convert to martensite and suddenly stiffens. STOP straightening immediately. Any further straightening can be done at the end of the second temper at around 400°F.
 
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