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Hello,
I have a fixed blade razor i'm making got it heat treated and tempered. I tempered it straw colored in the oven at 400 degrees C for 2 hours. But it's still harder then my Dovo, Sheffield. And my axe file won't bite into it. Should i retemper?
did you aim at particular HRC? If I am not wrong most razors fall in the 58-61 HRC range, Sheffields may be a bit softer.
For starters telling us what steel you're using would help. Also your heat treat procedure if you did it yourself.
Can't tell you the steel, I made it from a really old file. If i had to guess O1 tool steel. I heated it up to curie point then past a little for a few minutes quenched it in water. Heat treated for 2 hours at 400C.
400 C (750 F) would be much too high a tempering temperature for O-1. It should not skate a file. Most old files are W-1 or the like, that explains why it survived a water quench. The O-1 would have come apart.
Now if you mixed up the thermometer scale and it was 400 Fahrenheit....then try it at 425 F for another hour and retest it for hardness. If not to your liking then, 450 F for another hour. If it is Centigrade temperature, then I think you have a steel that is not behaving like a normal tool steel. Some stainless stuff will have a tempering cycle up to 1000 F but not something usual for a file either.
That's funny sorry i got the temperature scale mixed up.
I don't have an up to date picture. This ones right after hardening. Now it's grind, and shaped and partly polished. but it's still a little wide at the edge, i intended it to be a wedge but i can't hone it yet cause the upper part of the bevel is to thick and i can't get to the edge. It was taking so long on the 1000k i tried the file but it just skipped off. So is it too hard? It can almost scratch glass.
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if it can scratch glass then the HRC is 63 or higher.
I think you're off to a good start. Simply increase the temperature by 25 degrees for one hour. If you are patient and take that in steps you'll arrive at a hardness you like that won't abrade your stones.
Working with mystery steel has its challenges. O1, W1, S7 or maybe 1095???? Who knows. I have tried to look up which steels file manufactures use with no luck. Grind, grind, and grind some more. I don't expect that you will get to where you will be able to shape it with a file. When you do get it annealed then it is time to shape then re-harden it. Kind of a hassle to get right, when we don't know the steel. I have a couple of knives made from files. I have another 2 I softened with a torch. I brought one to the non magnetic state and quenched in oil. I had not drawn it back any and I broke it when rockwell testing it. The grain structure was huge. Drawing it back would have helped some but I will have to play with the HT process some more before I HT the 2nd blade.
Rambling, but I recommend grinding to shape then draw back slightly, no water quench. Do not worry to much about whether you can cut it with a file.
Jeff
Two things come to mind Jeff.
The first is that the file was probably overheated at some point if the grain size was large. It is possible with some simple techniques of thermal cycling to reduce the grain structure and salvage these.
Second, there are modern files that are merely mild steel that have been case hardened (very shallow depth of hardening) only meant to have hardened teeth. This saves a good deal on material costs, but often interrupts the blade maker's quest for a file worthy of making/recycling. Stick to Name Brands and preferably the older the better.
Hey,
I put it in at 75 degrees higher then last time, the steel went blue and it still skated the file! I thought steel softens when it turns blue? Anyway looked up W-1 steel and for 59 Rc it requires 500 Fahrenheit so i might go with 500 degrees unless someone here warns me not too...
Okay, one more thing. Try to gently file on this blue blade with a brand new file before doing anything else. Old files with the teeth partly used do not necessarily cut the same way as a new file. I admit this is sort of a subjective test, not the ideal tool shop engineering test, but fairly accurate for a good enough estimate.
The other problem is the type of controller on your oven unless it's a digitally controlled calibrated one. Sometimes, a kitchen oven is a good example, there can be a lot of swing around the set temperature, so the measurement of error around the set point can be higher or lower.
Yes it was very likely was over heated.
When i saw how blue it was my first reaction was "I wish this razor was sharp cause i know what i'd do with it..." But after i took the blue off it was still hard! I have a 2 week old file i tried on it and it took of the blue but when it got to the clean steel it skated over it, like it's not biting into it. Seems a little softer but still hard, i'm going to take it to a bet sander see if i can deal with the excess steel and test to see what edge it holds. But honestly i think it's probably ruined.
I wont get access to my sander for 2 weeks i'll let you know how it goes, thanks for your input.
Nathaniel
Ruined? No. You can always re-heat treat it and re-temper it. Steel can be very forgiving at times and other times it's a surprise. Like this one. It is entirely possible that it behaves in a way that is not predictable because it's an unusual steel for what all of us are guessing it "should be." The color tests that used to be pretty much a standard guide to the best estimate of how a steel behaved do not always mean what the chart says. Just like when a fellow says he forges at an orange heat, the next fellow says it looks yellow or red. Some of this is eye of the beholder material. The best observation you can make is how is this piece of steel behaving in my hands with my shop tools. Then you have to live with the possibility it's not W-1 or 1095 or what you thought it was. It's a mystery steel. Does it work as a razor when you get it all shaped and honed? Okay, now it's a mystery but it's a working tool.
Yeah. Steel is fun. I have this big slab of quality steel that used to be a large blade for a paper cutting machine (slicing the sides off of books).
I know it is good steel, and I know it can take a wicked edge. I just don't know how to HT it. I'll just have to try and see how it goes. Perhaps cut off a couple of test pieces, treat them, and test with a Rockwell tester (perhaps at the local uni)
111Nathanial, keep in mind that 63Rc is only a little tiny bit harder than 59Rc. If the file only just barely scratches the blade you are probably pretty close. See if it will hold an edge like you are planning. I'll bet its better than you are thinking.
Bruno, I use to sharpen those blades. The ones we sold and were common in this area had a HHS knife edge brazed to a High carbon carrier. The actual edge material was only about .060 thick and an inch or so wide while the body of the blade was about .375 to .500 thick and 6" wide (by memory and 25 years ago) up to 10 feet long. Yep wicked sharp, but to darned big to shave with.
Jeff
The main issue will be whether the main body is good enough to work with or not.
If the main body is plain steel, I can probably use it for making kitchen knives.
If the steel is good enough (I'll have to check using a HRc setup) I could make razors out of it.
If it is just low grade steel, I at least have a source for handle / tang material :)
If the carrier is indeed high carbon, It should be fine.
Couple of days ago I decided to cut it with an angle grinder, and that was... fun...
The 1.5 hp motor had trouble with it. Especially near the edge.
I'll post pics later today to keep everybody in the loop.
Angle grinder plus unknown steel equals spark testing.
Here's a start: Spark testing - Wikipedia, the free encyclopedia (there is a pending SOPA blackout).
Another: The Spark Test and Spark Testing Metals | Scrap Metal Junkie I like this one because the colors mean something and the length of the sparks too, not just the feathering.
