Thread: knife maker making a razor

@Boots:

As Mike Blue said above, tempering is not just to reduce hardness/increase toughness, it is also done to relieve stress in the hardened steel.

Quenching is very hard on the structure of the steel, relieving that stress means the blade won’t decide to crack whilst just sitting on the bench or when lightly knocked against something.

If using steel in its fully hardened state was a good idea, it would have been done before and the reams of writing on the process of tempering to get the desired (or at least useful) properties could have been saved.

5160 will meet the hardness criteria. Where that steel excels is in toughness. That explains it's strong use in spring applications. The only way to know for sure is make a razor out of it and shave with it. The biggest problem I have with spring steels is that you can't guarantee that old auto/truck springs are the steel you think it is. Given time and tools, making a razor and testing it will tell you a lot.

It's really easier, potentially a lot less heartbreak, to buy a bar of known steel and keep things simple.

Originally Posted by DrDalton

If using steel in its fully hardened state was a good idea, it would have been done before and the reams of writing on the process of tempering to get the desired (or at least useful) properties could have been saved.

As you say, reams of writing, on the subject, and there is just as much misinformation of not more. I'll probably never know as much as some of you guys have forgotten on the subject of HT. Like it or not, this forum is one of the few reliable resources out there, and I appreciate you sharing your knowledge. I know my incessant questions can be annoying, but I don't know anything about making razors, that's why I'm asking the pros.

Originally Posted by Mike Blue

5160 will meet the hardness criteria. Where that steel excels is in toughness. That explains it's strong use in spring applications. The only way to know for sure is make a razor out of it and shave with it. The biggest problem I have with spring steels is that you can't guarantee that old auto/truck springs are the steel you think it is. Given time and tools, making a razor and testing it will tell you a lot.

It's really easier, potentially a lot less heartbreak, to buy a bar of known steel and keep things simple.

I couldn't agree more, buy a known steel. I didn't mean to imply I was doing otherwise. 5160 is my favorite for larger blades because it's tough and the temper is very forgiving. I don't have any fancy equipment like a kiln so forgiving is important with sub-standard tools.

there is an additional consideration which I've meantioned a couple of times in the past: razors don't need toughness. At all. Only edge retention, a fine edge, and a decent hardness. That means that additional toughness doesn't add any quality to the razor, but it does make grinding and sanding a lot more difficult and annoying than it should be.

52100 for example is excellent stuff and I have made kitchen knives from it. For razors is doesn't give an edge that is better than O2 (which is my favorite tool steel) but it makes grinding and subsequent sanding at least twice as difficult and time consuming.

Originally Posted by Mike Blue

5160 will meet the hardness criteria. Where that steel excels is in toughness. That explains it's strong use in spring applications. The only way to know for sure is make a razor out of it and shave with it. The biggest problem I have with spring steels is that you can't guarantee that old auto/truck springs are the steel you think it is. Given time and tools, making a razor and testing it will tell you a lot.

It's really easier, potentially a lot less heartbreak, to buy a bar of known steel and keep things simple.

No doubt about it there, salvaged steels are not for me. Lucky for us we have the world at our fingertips these days and about any quality blade steel is available. The fear of that "heartbreak" you speak of has kept me from using salvaged steel, Id hate to get to the final edge on a finished project and find that a mistake in material was made. the horror hahaa


If one wanted to use 5160 it is easily obtainable in bar stock from the NJ steel Barron.

52100 for example is excellent stuff and I have made kitchen knives from it. For razors is doesn't give an edge that is better than O2 (which is my favorite tool steel) but it makes grinding and subsequent sanding at least twice as difficult and time consuming.

That's good to know, I'm working on my first razor from 52100. So far I haven't noticed any issues grinding it, but then I'm used to forging and grinding 52100, we'll see when finished if it's worth the extra effort of forging it and heat treating or to simply try 80CRV2 next go round, or even just plain 1084. I don't have any 1095 on hand.

I think 5160 would make a decent razor, but I don't know if it would be enough of a difference between other steels, only way to know would be to test them out. The thing about 5160 is that it's a little low on carbon, but the chromium content aids in hardening so you can get a blade in the 59-61 RC range while maintaining chip resistance. Also, from my understanding, it's the carbides that do the cutting, and chromium carbides are tougher than carbon carbides. 5160 properly heat treated will have very small grain size as well which lends itself to a very fine edge, but 1095 will be slightly finer, if not quite the edge holding, so the only real way to know is make two and test side by side. This is all theory when applied to razors though. For the best 5160 I've ever used see if you can get a John Deere load control shaft, it's 5160 that is held to JD's specs which are a lot tighter than the nominal steel industry standards.

As for the original poster, I'm in the same boat, having to learn to look at things differently from knives and there is a learning curve I'm slowly climbing. A straight razor is surprisingly complex for a simple sharpened bar of steel, but then the same can be said of knives.