Can Someone confirm what I already know, but hope I'm wrong.

[clyde72]

I'm new to straight razors and restoration.
I got this razor as part of an estate lot. Online pictures weren't very detailed or good. I'm not out a lot of $$ so if it toast its toast.
To me it looks like someone used a buffing wheel to restore it and got it way too hot. The coloring tells me this right? Be nice if I wrong. But if has been this hot the blade is ruined right?

Thanks!
Craig

 

[sfeile]

That is kind of what it is looking like. Or a grinder. If it was heated to get that color, it has no temper left.

 

[clyde72]

That is kind of what it is looking like. Or a grinder. If it was heated to get that color, it has no temper left.

Yeah that is what I was thinking. I don't see any grind marks, so I'm thinking dremel.

Well it'll make a good practice razor when I decide to learn to hone. Won't have to worry about messing it up. Or I can see what kind of polish I can get on it.

Thanks for replying!

 

[Hoka Hey]

I'm looking at the pic on my phone, but I believe you are right, on both points. Toasted on a buffing wheel. The bluish haze on the tip says so.

You could salvage the scales. Maybe try and save the blade via heat treat/temper. That's iffy with out knowing what specific steel it is. Got an Oxy/Acetalyne torch handy?

 

[sfeile]

Yeah that is what I was thinking. I don't see any grind marks, so I'm thinking dremel.
Thanks for replying!

Very possible it was a dremel. Straw/brown colors, and you are reaching the heat it was tempered at. Blues and beyond, you have surpassed that temperature and ruined the temper in those areas.

 

[clyde72]

I'm looking at the pic on my phone, but I believe you are right, on both points. Toasted on a buffing wheel. The bluish haze on the tip says so.

You could salvage the scales. Maybe try and save the blade via heat treat/temper. That's iffy with out knowing what specific steel it is. Got an Oxy/Acetalyne torch handy?

Re-temper??? Well I certainly couldn't make it worst.
Thanks!

 

[sfeile]

Re-temper??? Well I certainly couldn't make it worst.
Thanks!

The blade has already been hardened. You could try removing it from the scales and putting in your oven. Around 400 degrees until it is fully reached that temperature, then let it naturally cool. Don't dunk it or fan it, just let it cool slowly on it's own. May be enough to re-temper the blade.

 

[Hoka Hey]

Re-temper??? Well I certainly couldn't make it worst.
Thanks!

Of course you can!

Since the temper is gone, you have to start all over. Heat treat, quench, then temper. I've never done it with a razor, but have with a few knives. The trick with a razor is to not burn the thin edge. Burning is going to far above the ideal heat treat temp.

Might be able to do the heat treat with MAPP gas. Quench in Tranny fluid. You can temper in your oven. Let me know if you want to attempt it, and I'll try to give you some guidance. If you know a knife maker, blacksmith they could probably help with a little information. Blade down, and torch on the spine only. Assume the steel is 01, or close enough for the heat treat/temper specifications.

And yes, what do you have to lose? I'd give it a go.

 

[sfeile]

Of course you can!

Since the temper is gone, you have to start all over. Heat treat, quench, then temper. I've never done it with a razor, but have with a few knives. The trick with a razor is to not burn the thin edge. Burning is going to far above the ideal heat treat temp.

Might be able to do the heat treat with MAPP gas. Quench in Tranny fluid. You can temper in your oven. Let me know if you want to attempt it, and I'll try to give you some guidance. If you know a knife maker, blacksmith they could probably help with a little information. Blade down, and torch on the spine only. Assume the steel is 01, or close enough for the heat treat/temper specifications.

And yes, what do you have to lose? I'd give it a go.

I'm not an expert by any means, and don't want to knowingly give false information, so I'm asking for my own curiosity as well.
Would he need to go all the way backwards to re-heat treating? Or would just re-tempering be enough?

Also, if the temper being taken out in parts of the blade are going to affect it enough that he has to heat treat it again, should it be annealed/normalized again before heat treat?

 

[Hoka Hey]

I'm not an expert by any means, and don't want to knowingly give false information, so I'm asking for my own curiosity as well.
Would he need to go all the way backwards to re-heat treating? Or would just re-tempering be enough?

Also, if the temper being taken out in parts of the blade are going to affect it enough that he has to heat treat it again, should it be annealed/normalized again before heat treat?

The blue indicates the metal was heated beyond the temper temperature. The only way to restore uniformity is to start at the beginning. In a sense you are heat treating to normalize, then quenching to harden.


Annealing (softening the metal by heating followed by open air cooling) would only be useful if you wanted to do work on the blade, file work on the spine, etc. Then you still need to heat treat/quench/temper. Make sense?

I'm curious now how straight razor makers do their heat treat. I'd probably go for the salt bath method. Doing it in the forge seems like it would be risky. Torch seems solid in comparison. Have to look into that some time.

 

[bluesman 7]

The HT (quench and tempering) is done before the final grinding so there is a lot more metal to keep the blade from warping. The blank is normally austenitized (heated above critical) in a well controlled forge or a heat treating oven in low production settings. Many of us prefer the forge over the oven because you can sense the transition to austenite easier and the quench can happen more quickly than opening the oven and grabbing the blank with tongs while cold air is rushing into the oven.

It is not impossible to HT a blade after the final grinding, I helped someone do it once, but there is a high likely hood of catastrophic failure and the more hollow the blade the less likely success would occur. If I had not been there and seen it, I would not have thought it possible and we were all surprised that it worked. We did this in a forge.

 

[sfeile]

The blue indicates the metal was heated beyond the temper temperature. The only way to restore uniformity is to start at the beginning. In a sense you are heat treating to normalize, then quenching to harden.


Annealing (softening the metal by heating followed by open air cooling) would only be useful if you wanted to do work on the blade, file work on the spine, etc. Then you still need to heat treat/quench/temper. Make sense?

I'm curious now how straight razor makers do their heat treat. I'd probably go for the salt bath method. Doing it in the forge seems like it would be risky. Torch seems solid in comparison. Have to look into that some time.

Makes sense.
I've not made any razors or knives personally, only watched videos on them. The ones I have seen anneal/normalize during the forging process. (Fixes the micro-structure) Heating, holding temperature, then cooling slowly in an insulated container. After forging is complete, they heat treat (normally forge then oil quench on the ones I've watched) followed by tempering to slightly soften it back up just a little so it's not so brittle, then final grinding.

My thought was even though it had turned blue, above the tempering heat, it still hadn't hit the temperature used in heat treat. Thus in my thinking, it should still be hardened, but not necessarily consistent.

Now thinking it over more, it was above the tempering heat in spots, so the molecular structure may be messed up. That would require annealing it again to straighten it out. Then heat treat to harden it back up, followed by tempering.

The big problem I can foresee with having to go back that many steps, is that this is already a finished blade. The heat from annealing and hardening such a thin blade is probably going to warp the crap out of it. Also the scale from hardening is going to need to be ground off. Looks like a half hollow or thereabouts, so there isn't much material left for that step.

 

[Hoka Hey]

The HT (quench and tempering) is done before the final grinding so there is a lot more metal to keep the blade from warping. The blank is normally austenitized (heated above critical) in a well controlled forge or a heat treating oven in low production settings. Many of us prefer the forge over the oven because you can sense the transition to austenite easier and the quench can happen more quickly than opening the oven and grabbing the blank with tongs while cold air is rushing into the oven.

So how much material is left to remove following HT? Knife making it was under 10%. Just curious. Realizing more and more that what I know about knives is a world away from what I need to know about straights. I hate math, but realize I need at least a basic understanding of trigonometry for straights.

 

[bluesman 7]

I leave about 1 mm of thickness. Here are two blanks ready for heat treating.

 

[Hoka Hey]

Makes sense.
I've not made any razors or knives personally, only watched videos on them. The ones I have seen anneal/normalize during the forging process. (Fixes the micro-structure) Heating, holding temperature, then cooling slowly in an insulated container. After forging is complete, they heat treat (normally forge then oil quench on the ones I've watched) followed by tempering to slightly soften it back up just a little so it's not so brittle, then final grinding.

My thought was even though it had turned blue, above the tempering heat, it still hadn't hit the temperature used in heat treat. Thus in my thinking, it should still be hardened, but not necessarily consistent.

Now thinking it over more, it was above the tempering heat in spots, so the molecular structure may be messed up. That would require annealing it again to straighten it out. Then heat treat to harden it back up, followed by tempering.

The big problem I can foresee with having to go back that many steps, is that this is already a finished blade. The heat from annealing and hardening such a thin blade is probably going to warp the crap out of it. Also the scale from hardening is going to need to be ground off. Looks like a half hollow or thereabouts, so there isn't much material left for that step.

The main problem is that it's a finished blade. There is little margin for error, and the chances of success are slim. Right now it's a letter opener. There is a chance of warpege. There is a chance of frying it. It's a paperweight right now. It may end up being a paperweight.

I propose that a talented hand with a torch could run the spine, watch the edge, quench, temper, and be done with it. And the truth is the same talented individual might bend it. Odds are against.

Another method would be to put refractive clay on the edge. Gets complicated as you can't see what's going on.

 

[Hoka Hey]

I leave about 1 mm of thickness. Here are two blanks ready for heat treating.
View attachment 785607

Your running it in tight. Are you using a 12" wheel? Actually they both look different. Shadow and whatnot.

 

[Hoka Hey]

So the edge is left thicker than the mid blade?

 

[bluesman 7]

No, the edge is the same thickness as the mid blade on those blanks. Most makers HT with closer to a quarter hollow grind with the edge between a nickle and a dime in thickness, I prefer to take more metal away before HT as I'm headed towards a full hollow anyway and the steel is easier to take away before HT.

Going to bed now, we can talk more tomorrow if you would like.

 

[Doc226]

Before getting crazy here, I would clean up with a meal cleaner, honer and try to use.

It could be the temper is gone but it could just be some kind of oxidation.

 

[bluesman 7]

Doc makes a good point. Sorry for getting so far off topic.