Thread: Overcooked?

I just noticed that in the pictures, the darker colours seem to be on the tangs, where they may not have been quenched (or not as much). I'll see if I can verify this as well as the file test. If it's not so soft that the file bites I'll continue on.

I think they're ok.

On second thought, the file seems to cut.



However, they didn't do this before tempering, and if the file is rc65 and the steel is 59, this is expected, no? The file 'almost' skates unless you use pressure.

I use my oven too, but I let it stabilize in heat before I add the blades and I use the center of the oven. Using the bottom of the oven close to the heat can lead to finding hot spots. Hot spots on the thin metal (the important part...the edge) can get them a lil soft.

You can take a chance and do the final grind...or just HT again & play it safe.

Using a cooking oven can be done. It has the risk that the set point for the temperature can swing too low or too high depending on the accuracy of the controller and thermocouple sensing system. Sometimes as much as 50 degrees or more. A loaf of bread probably doesn't matter so much. But, you can, over time and a bunch of blades, fiddling with the temperature setting and checking the hardness develop a familiarity with the oven that can overcome some of the error and you can get pretty reliable after a while.

Looking at the new pictures I see a nice color down to the edge. Well it looks like a color I would be happy with.

I agree with Shooter, take a chance or HT again and this time stay below 400F in the temper. If it's a bit lighter yellow/straw you're good. There is nothing wrong with Rc 59. The fellows who have to hone blades will thank you for caring about their feelings. LOL

Ok, I did. Probably wasn't necessary by the feel of it on the belt grinder beforehand. I sanded them up and then put them in the forge while it came up to temp. Then when orange and non-magnetic, quenched in canola, and then sanded again.

I coated the blades with fire clay but I think that was a waste of time, as it all flaked off the blades and the only parts that stuck were probably wet (on the sides of the shoulders) and was a pain to sand off.

Thanks guys. In retrospect, if the colour looked ok for Mike Blue, I should have left it rather than risk grain growth, but hey, it's all experience.

Seems a shame to use the oven in summer but I will try to keep these moving. I might try the convection setting on the microwave/oven (no nuke of course).

Originally Posted by Atchbo

... if the colour looked ok ... I should have left it rather than risk grain growth, but hey, it's all experience. ...

You were the one with the blade in your hand at the time. All of us can have an opinion from a distance, but it's the fellow with the job in front of them that has to make the decision. Usually, heat treatment temperatures won't affect grain growth if they are above austenitizing temperature and below the coarsening temperature.

A lot of forges are not controlled as well as they could be, and then grain growth can be a potential issue. Basically the forge is On or Off and there is little adjustment of the fire in between. You're HTing ten blades, the first three turn out okay but the last seven all have problems. The forge continues to run upward from a good temperature to screaming hot by the time the job is done. Eventually you learn to do three blades and quit and let the fire cool down and do the rest in batches later (the less expensive method).

A well controlled fire will hold the same temperature consistently no matter how long it runs. One of my small forges (a Randal Graham design) will hold a set temperature until the gas runs out. Blades can sit there for a long time without overcooking. I've had to "tune" it, using the wet computer, a bit for different altitudes and relative humidity. Once the adjustments are made it's a fine little fire. Salt tubes operate similarly whether electric or gas, but then you have solenoid controllers and such (expensive).

If the blade shaves you did a good job. If it hones harder, or easier, the man with the stones will tell you. Each blade will talk to you and tell you what it wants. LOL

I just want to add that 57 and 58 are not exception among old Sheffield razors, so that shouldn't be a problem at all as long as you stay above 57.

One hour at 400oF.



With flash


Up close