Re-hardening a vintage razor?

So a few weeks back i sent my razors in to get re-honed and ready for the new year and to my surprise the honer wrote back that a few of the blades were to soft to take a razor's edge. And that got me thinking do razors get softer with age ? do the decades of stropping, honing, water interaction weaken the metal the razor is made out of. And is it feasible to re-harden these worn out blades or just keep then as decorative reminders of the past.
Has any one had this issue or hows why this happened.

PS- I trust my honer when he says they can't be sharpened as is, and i can't wait to get all my razors back and shaving.

I have never heard of a blade losing its temper from anything other than overheating. Could you post more details and/or photos?

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Originally Posted by honorakr

So a few weeks back i sent my razors in to get re-honed and ready for the new year and to my surprise the honer wrote back that a few of the blades were to soft to take a razor's edge.

PS- I trust my honer when he says they can't be sharpened as is, and i can't wait to get all my razors back and shaving.

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So here are the big questions...

If your razors have just been "re-honed," then who honed them before? (I don't need a specific "who," simply, was it the same or a different honer?)

How did they shave?

How long did they shave?

Is it old Sheffield steel? Sometimes that stuff will fall apart along the edge until the soft stuff is gone and then it will take a good edge once again. When this happens there is usually a lot of work to get down to the good steel.

In a word, no.

They will not get softer through use and can not easily be re-hardened.

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Originally Posted by holli4pirating

I have never heard of a blade losing its temper from anything other than overheating. Could you post more details and/or photos?

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Dylan is dead on. Only thought other than heat is if it's surface hardened and you have worn through the hard steel exposing a softer core.

If it's a wedge to a quarter hollow, maybe on a new HT. You will have to keep in mind it's a mystery steel, that you will loose about an eighth of an inch in length, and the blade will still need cleaned up. Most who heat treat would pass on such a venture & honestly most blades aren't worth the money and effort. If it's a half hollow to full hollow...forget about it as it will most likely potato chip or crack at the quench.

i don't know much about the blades before i came to own them .I cleaned them and gave a light restoration to them.in terms of the blades , one is a yankee cutlery 5/8 (germany), a hope cutlery (germany), and a small mustache razor ( unknown). here are some of the pictures before the restoration i didn't take a picture of them after the restoration yet.

here is a snipit of the conversation-"The problem with these seems to be their steel. They seem soft like they have lost their temper. I noticed this when I set the bevel on these and there was no keenness to them, they should produce the feeling of a rough edge on the thumbnail but they did not. I didn't want to remove any excess steel to see if I could get to better steel so I am returning them as-is"

Attachment 194163Attachment 194164Attachment 194165

The steel will not lose its temper by sitting. One possibility with old thick razors is that the steel was originally softer in the center moving toward the spine, and that years of honing exposes the softer steel. But these are modern production and quite hollow. Just looking at them I see no visual reason why the steel should be too soft. The razor on the top needs to have its heel reworked, it has quite a frown. Honestly, I would say that one's not worth the effort.

As far as hardening, these are far too thin / hollow to reharden. And would definitely not be worth the effort IMO.

If it's worth it to you, you could try sending them to another honer (though I agree the first is not worth the effort) to see if someone else can get the bevels set properly. I don't know who you sent them to, and I certainly am not jumping to any conclusions about that person's skill, but it seems odd that they shouldn't take edges.

So these were not previously honed by someone else and then used by you?

Are you confident in the skills of the honer who judged these blades? The larger two blades' photos do not appear to have come close to a set bevel.

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Originally Posted by Utopian

So these were not previously honed by someone else and then used by you?

Are you confident in the skills of the honer who judged these blades? The larger two blades' photos do not appear to have come close to a set bevel.

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I think that they are before photos

There are anecdotal reports of steel blades (old swords of legendary quality being tested later to find they are not so legendary) losing their hardness. But, the blades referred to are centuries old. Essentially hardening steel introduces energy into a crystalline structure that is then subject to the disorder of the laws of thermodynamics. I doubt any of us will live long enough to test this proposition. We can't go back in time to hardness test old steels and then leave them so we can test them later to know. It's an interesting thought problem though.

I have rehardened newly ground wedge (8-12 inch diameter wheels) style razors using controlled temperature salt baths. Definitely a style of grind with a radius to the edge not a flat blade with a tight radius at the spine. I knew everything about the heat history of the material through making the blades and coordinated the efforts with those grinding them. Two thirds of those potato-chipped along the edges up to about 200 thousandths. The resulting blades were hard, but had moved from 8/8ths to 6/8ths. About a third could be predicted to remain with a stable edge. I have not attempted vintage blades except Herders and those were not near a finished edge.

For the most part, I would not recommend attempting to re-heat treat a vintage blade or one that had been taken to a finished grind (pre-bevel set). It can be done, but should not be without the expectation of losing some of the blade width in the process. Luck is simply a variable that cannot be denied.

Color changes from overheating can be polished away. There is a legitimate question about honing technique that has not been resolved in this discussion or subsequent evaluation of the blades. Still too many questions.

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Originally Posted by edhewitt

I think that they are before photos

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Thanks that makes a lot more sense.

I still find it very strange that 3 vintage blades were judged to be too soft at the same time.

Honorakr, would you please clarify what sort of light cleaning and restoration you did? I'm wondering if you did anything to alter the temper of the blades.

Honestly do not think there a many Vintage blades worth the time,effort, and money that would warrant being re-hardend,JMO