Tempering a scribe\marking knife.

[Kessik221]

I have a project I'm working on for a marking\scribing knife for a friend who wants one for metal work. It's made from 1095 carbon. Usually i just heat it up to non-magnetic quench it in oil and temper for 2 1-hour cycles at 400 degrees for a normal knife, is that what i should do for a marking knife or should the hardness be greater?

 

[scott.livesey]

you want a high a hardness as possible. probably 1 hour at 300F, ice water quench, then 1 hour at 275F. you should get a hardness around Rc64-66.

 

[Kessik221]

thanks!

 

[Stacy E. Apelt - Bladesmith]

The best choice for a metal scribe is carbide. Steel at high hardness will chip sooner or later no mater how you do the HT. A stick of carbide for making a lathe tool, a diamond grinding wheel or lap to shape the tip, and diamond plates to do the final sharpening and smoothing will make a tool that will laugh at his stock as he scribes it.

You can find it really cheap on ebay ( around $4-5 a piece for 6" long stock) or order from industrial suppliers like McMaster-Carr.

 

[kuraki]

All my self made scribes are broken 1/8" carbide endmills.

 

[John Blazy]

All my self made scribes are broken 1/8" carbide endmills.

Beat me to that one. I never throw out my broken carbide mills. Chuck em into a drill then grind to a perfect point on the diamond wheel. Then I lose them, and start all over again.

 

[Stacy E. Apelt - Bladesmith]

Same here, broken carbide bits and such get re-ground into other tools.