F Herder "NOS" straight razors

[Dzaw]

Here’s what I can do to the spine of the one I just put on a hone for a few seconds with a very soft steel knife.

It’s looking like the stuff on the outside is hard and brittle. Inside is soft. Again, trying the same on even my softest razor has the razors striations filing away at the knife.

Anyone work with steel? Is it possible they tried to harden, but didn't heat the steel enough and got a hard/brittle exterior and soft interior? Cause this black stuff outside isn't simple patina. It's like scale. It's brittle, chips off, and hard as nails. Inside is soft, useless steel.

That's because it /is/ scale

Is it possible these are drop forged blanks? If so, they would have a very light coat of scale all around the outside, but it wouldn't look anything like the "scale" that piles up while a hand shaping smith heats and reheats, it would be a single skin tight layer.

Similarly, if they tried to harden using relatively simple tools for the job, the entire outside skin could oxidize and would form a black scale skin before the quench. That's not such a problem in an of itself, but it also can indicate a decarburized condition of the steel. Carbon loves oxygen even more than iron does, and if allowed to be released from the iron matrix, it will flee, leaving behind soft iron. That's a pretty easy way for a relatively new hand at heat treating to ruin an otherwise good blade - too much heat for too long.

A common problem newer knifemakers often have is that their knives seem to take and hold an edge like crap for the first half dozen or so sharpenings. Then, after a while, suddenly, the knife will be able to take and hold an edge. The decarb'ed steel gets ground away, and underneath it is the properly hardened steel.

In your shoes, I would take one of the razors I had already ruined my chances to return, and try grinding away at the edge with some 600 grit - hone it like I MEAN it for a while. Then try setting and refining a bevel. There might be hard steel under the decarburized iron.

 

[SliceOfLife]

Thank you for the suggestion. I’ll give it a try and post results.

 

[P.G. Gibson]

I bought some of these last week. I ground in below what I’d consider to be an acceptable depth for decarb and they test below 40 HRC according to my reference files. But they aren’t MUCH below that. I’ve messed around with a lot of the other Herder old stock blades - everything from tableware to large carving knives in various states of completion. Even on the near completed carving blades that were already finish ground, they are on the soft side. That being said, they are also very resilient and don’t take a set super easily when you attempt to bend them. The carving knives I got a hold of years ago actually hold an edge decently. Don’t know if that info helps, but I thought I’d offer it up!

 

[Dzaw]

I ground in below what I’d consider to be an acceptable depth for decarb and they test below 40 HRC according to my reference files.

Dang. I guess they weren't hardened then. With such a thin profile even air cooling will form some martensite mixed into the pearlite and retained austenite. Basically an iron and carbon soup rather than proper steel.

If you've the equipment, you could try hardening them yourself I guess, but aside from that, I doubt they're going to be serviceable as razors.

 

[SliceOfLife]

I bought some of these last week. I ground in below what I’d consider to be an acceptable depth for decarb and they test below 40 HRC according to my reference files. But they aren’t MUCH below that. I’ve messed around with a lot of the other Herder old stock blades - everything from tableware to large carving knives in various states of completion. Even on the near completed carving blades that were already finish ground, they are on the soft side. That being said, they are also very resilient and don’t take a set super easily when you attempt to bend them. The carving knives I got a hold of years ago actually hold an edge decently. Don’t know if that info helps, but I thought I’d offer it up!

Thanks for the confirmation. That’s basically what I was worried I was dealing with. I’m sending the eight I haven’t tried honing back. Maybe someday when I have a lot of free time on my hands I want fun project I’ll try hardening the other two.

 

[P.G. Gibson]

I actually checked the tail too, and it was around 40 also - but it is tapered and fairly thin too, so that could indeed be air cooling after the forging operations.

I talked with a friend who was approached to do the finish grinds on these for SMKW and they gave him a sample to play with. He said the same thing - seemed soft.

I'm going to put a few through the kiln and treat as if they were 1084 and see what kind of numbers I can get. I'll post back after I do. I'd really like to be able to rescue a couple to add to the rotation!

 

[SliceOfLife]

Good luck man, definitely looking forward to your results. Is it a forging kiln or do pottery kiln get that hot? I was thinking of just doing the propane torch technique that you see online for peoples scissors and cheap knives, but my wife’s friend actually owns a pottery studio, so I could just convince her to let me slip a razor into one of the kilns there it might be a little bit more reliable

 

[Dzaw]

1084 austenizes just shy of 1400 F. Any hotter than 1500 and you get disgusting runaway grain growth. Most pottery kilns can get quite a bit hotter, so you need to be able to control the temperature.

If you do the torch method the chance of overcooking the edge goes up dramatically, but with careful and thoughtful coating and treatment, I suppose it could be accomplished.

Quench in a fast oil, not water. These blanks are too thin for water and you’re very likely to crack or outright break it. If you can’t find a good source for a fast quenching oil (very hard to get in small quantities) the I’ve heard people have success with peanut oil, and some other improvised quenchants.

Once quenched cool to room temp, then temper two hours in an oven at 400F, cool to room temp, then another 400F temper for another two hours. This should result in a rough ~60 HRC.

 

[Dzaw]

You could probably make it a little harder with a 350F temper, but you might be riding the line for micro chipping while honing, I don’t know...

 

[P.G. Gibson]

It is digitally controlled kiln designed for heat treating blades - but a good pottery kiln can get it done too!

 

[SliceOfLife]

1084 austenizes just shy of 1400 F. Any hotter than 1500 and you get disgusting runaway grain growth. Most pottery kilns can get quite a bit hotter, so you need to be able to control the temperature.

If you do the torch method the chance of overcooking the edge goes up dramatically, but with careful and thoughtful coating and treatment, I suppose it could be accomplished.

Quench in a fast oil, not water. These blanks are too thin for water and you’re very likely to crack or outright break it. If you can’t find a good source for a fast quenching oil (very hard to get in small quantities) the I’ve heard people have success with peanut oil, and some other improvised quenchants.

Once quenched cool to room temp, then temper two hours in an oven at 400F, cool to room temp, then another 400F temper for another two hours. This should result in a rough ~60 HRC.

Yeah, that's almost exactly what I've been reading on the home methods... except the coating... I assume it's some kind of paintable carbon I need to coat it with? Most of my reading seems to assume the blade is already full of carbon, it's just the structure that needs to be adjusted with shocking and tempering.

 

[P.G. Gibson]

I’m with Dawz - you *can* do it with a torch (there are ways) but I don’t think I’d go that route on these razors. There are already quite a few unknown variables

 

[Dzaw]

Yeah, that's almost exactly what I've been reading on the home methods... except the coating... I assume it's some kind of paintable carbon I need to coat it with? Most of my reading seems to assume the blade is already full of carbon, it's just the structure that needs to be adjusted with shocking and tempering.

If you have *ANY* better method than a torch, you won't need to coat at all. Coating is something you *CAN* kind of use to try and rig your way around having to use a better method if you absolutely have to use a forge or torch to harden.

If I were going to do this with a torch method, I would get a stack of firebricks to form an oven and use the torch as the burner, basically making a little forge. I would mix iron filings and charcoal dust and I would pack the blade in that mix so that the spine was exposed, but only just, and the whole body of the blade was packed into a trough of the iron and charcoal mix. You could make this little trough by beating some black iron pipe with a hammer. I would treat the whole trough as my workpiece, and I would heat it in my makeshift kiln in dimly lit conditions, pulling it out pretty often to watch for decalescence. If you need a primer on decalescence, let me know, I can describe it for you but this is already a long post. Keep a few pairs of tongs handy, or at least long handled channel locks. Once the spine of the blade shows signs that it is transforming, you have like a second to pull it up out of its bed of protection and plunge it into the quench.

With oils for quenching, you need to be aware that there is a real possibility the surface will catch fire as you plunge the hot metal in. The best way to avoid this is to move quickly - it isn't actually oil that burns, it is the vapor just on top of the oil as the oil evaporates. If you do have a flash, you're going to want something solid on hand to smother it with.

 

[P.G. Gibson]

Ok WOW. So yeah - these puppies get plenty hard.

I did some normalization cycles at 1550F and 1350F in SS foil and then did 1500F with a 9 minute soak and quenched in DoBois #50

Straight out of the quench a 65HRC file doesn't touch it (even when giving it the beans). So yeah - definitely potential.

I'm going to run it through a 390F temper twice and see what it comes out to. Very exciting!

 

[Joshua223]

Ok WOW. So yeah - these puppies get plenty hard.

I did some normalization cycles at 1550F and 1350F in SS foil and then did 1500F with a 9 minute soak and quenched in DoBois #50

Straight out of the quench a 65HRC file doesn't touch it (even when giving it the beans). So yeah - definitely potential.

I'm going to run it through a 390F temper twice and see what it comes out to. Very exciting!

View attachment 982762 View attachment 982763 View attachment 982764

Nice! I figured someone with the right equipment and skills could probably make nice razors with these kits, so it will be cool to see how they turn out. I didn't realize a razor maker here was trying them.
What type of grind do you have planned for it?

 

[Dzaw]

Yes indeed! That’s a promising start!

Let us know post temper how the finished product tests. At 390 I would wager in the 62-64 vicinity if indeed it’s 1084.

Nice that you had the SS foil on hand, they should clean up real easy!

I don’t know DoBois - but I knew a #50... did they buy Parks? Is that the fabled “near water” fast oil I think it is?

 

[SliceOfLife]

Would you be interested in hardening razors for others? If so about how much would you expect to charge per?

 

[P.G. Gibson]

I'm no razor smith, unfortunately (someday, Lord willing!) Just a hobbyist knifemaker.

Dawz hit the nail on the head - they came out at what feels like around 63-64 based on the tests. HRC file tests are pretty subjective, but that is what it feels like based on my experience. I did two 1 hour cycles @390F. I should mention (and this is pretty incredible to me) - it didn't warp a bit.

The DuBois #50 is pretty much the same thing as Parks from what my supplier tells me, but I don't know if they changed hands or not. I've had great luck with it on 1095. I would have used a slower oil, but I only had the #50 on hand. Seemed to work ok though! The SS foil is a God send. Beats the snot out of cleaning of satanite out of the bottom of the quench tank!

I've never ground a razor before, so I'm not really set up for it (my smallest contact wheel is 8") but I roughed it out a bit on the idler wheel of my old clapped out 4x32 Delta for the tests. I've got it down to about 15 thou from the 21 it started at and so far it looks... well, it is almost passable. We'll see. Not exactly the ideal tool for the job.

As to doing heat treats for others - I would love to but I probably couldn't do it nearly as cheaply as a professional heat treating house. Also I want to respect the BB rules on that kind of thing since I'm not a commercial member.

But fear not! Once we establish a baseline HT for these that passes muster, it is a pretty simple matter for any of us to send it to a professional HT house for a very reasonable rate (less than $40). They actually run one-offs like this all the time for custom makers, and all the HT places I've talked with over the years have been super helpful and nice. In fact, I wouldn't be surprised if they've already seen a few of these razors come through already. They may already know exactly how to handle them! Finding someone to grind them is probably the hardest part of this, in truth.

I plan on finishing this one out at its current temper to the best of my abilities and then sending it out to a honemeister for their professional opinion on the HT result. I fear it is going to be chippy.

We shall see!

 

[Dzaw]

Awesome.

You really don’t need a slower oil for 1084 (assuming that’s what we’ve got here), just avoiding the vapor barrier that water forms is critical to not cracking. You normalized well, so I’m not surprised they didn’t warp on you.

At 63 HRC, it may be a bit chippy, but there’s no extra carbon and little in the way of carbide forming elements, so tear out shouldn’t be a problem. It would seem to me you probably have a first rate shaver in your hands! Get that profile hollowed out just a bit and it could well turn into your favorite shaver!

 

[P.G. Gibson]

Yeah I'm looking forward to getting it on the stones.

I was expecting warpage primarily due to the fact I had done a really rough pass on the faces to do my initial scratch tests and these things are pretty thin on the edge. I figured I'd have some bacon on my hands. But it did well! I also ran my oil cooler than I normally would which slows down the quench a bit (just in case).

Excited to see how things develop.