Thickness of Hitachi Blue #2 before HT

[Robert Erickson]

I'm finally getting around to grinding the Hitachi Blue #2 I got from Aldo a year ago. I'll be be doing gyuto and honesuki profiles with blades between 6-8".
I'd like to grind a fair amount pre-HT so I don't have far to go afterwards. I know that it is VERY temperature sensitive after HT.
I'll be sending them to Peter's for HT.
How thin can I go?

Thanks,
Robert

 

[HSC ///]

any forging or straight stock removal?

I wouldn't go thinner than .04-06
If you want a clean ground finish throughout, then you want to leave it thicker and grind off all HT scale

here is 3 Hitachi blue forged from one bar that I just did

 

[Robert Erickson]

I do stock removal

 

[samuraistuart]

Peter's has their own "rules" or "guidelines" for carbon and SS. You'll have to check their site. It is generally recommended that carbon steels should have an edge no thinner than .020" pre heat treat, which is what I use without any issue. I actually took a Blue 2 chef knife to .015", but did experience some minor ripples, taken out during post heat treat grinding/polishing. I could not recommend anything thinner than .020" for carbon. SS is a different story...because the quench is slower, still air or quench plates, you can go to just about final dimensions pre HT. Good luck!

 

[HSC ///]

don't forget the cladding is just mild steel and and grinds away freely.
I do all my grinding post HT, but I realize everyone has their own preference

 

[Stacy E. Apelt - Bladesmith]

Do yourself a favor and don't grind much ... or any ... on the bevels.

Your best bet is too take the bevels down after HT.

Run the grinder at half speed and dip-grind-dip-grind.

If you feel you have to grind, don't take them down any thinner than .05"

It will be a bunch of work finishing them in any event. This steel is HARD at Rc63-64.

One reason I like to do a clay coat and get the upper part softer is that makes the shaping a LOT easier. I also like to torch draw the spine down.

This is why I really love the soft iron sided san-mai with white/blue steel core. The iron sides stay soft while the edge gets as hard as you want it. Grinding post HT is very simple. I often leave the san-mai at Rc 64 on fish slicers

 

[Robert Erickson]

Got it. Thanks guys! The stuff I've got is the HB#2 mono steel that Aldo had a while back so I'll just have to take it slow.

 

[Willie71]

I just did a couple Hitachi Blue knives from Aldo's stock. That stuff takes forever to sand. Get some good belts, double the number you think you need, same with sandpaper. This stuff is HARD!!!!

I went to 0.040" prior to heat treat. It will get a pretty nice hamon as well. Lots of alloy banding in my piece. The hamon is lower than I typically like, but it does not touch the edge. The owner reports 20% better wear resistance than W2 at the same hardness, RC63/64.

[/url]image by Wjkrywko, on Flickr[/IMG]

 

[Robert Erickson]

Looks like a great blade Warren! I'm pretty excited to see how this stuff works once finished.
The next question is can you take the final edge, before sharpening, down to 0.005" or so?

 

[Willie71]

This one was 0.003", 11 deg/side. Customer has a walnut/cherry/maple end grain cutting board, so we go thin and hard for his knives. Offset grind.

Here's the other side:

[/url]image by Wjkrywko, on Flickr[/IMG]

The knife was an exchange for the Koa he brought back from Hawaii when he was on vacation. He wanted one knife with a piece of the Koa. We're both pleased with the deal.