Sawing a Completed Blade and Tempering?
- Thread starter JohnR001
- Start date
Horsewright
Knifemaker / Craftsman / Service Provider
- Joined
- Oct 4, 2011
- Messages
- 11,682
Yes, sawing, grinding anything that cuases enough heat that the steel changes color is the short answer.
What if I grind it and water it down now and then?
- Joined
- Oct 18, 2018
- Messages
- 5,556
I don't know how you would saw a Hardened blade?
But Yes, you need to be careful while grinding a hardened blade.
You can grind them.
I've done it Alot. I get all my blanks hardened before I grind my bevels.
Keep it cool, dip it in water often. Stay away from the tip, or be Very Careful there, as it will heat up at the tip faster than elsewhere on the blade.
Keep the blade moving, don't dwell in one spot. Use coarse new belts.
I use a disk cut off wheel first to remove alot of material (and dipping in water), leave a little extra, then clean up on the 2x72 grinder
Horsewright
Knifemaker / Craftsman / Service Provider
- Joined
- Oct 4, 2011
- Messages
- 11,682
When he said sawing I was thinking of an angle grinder too
Yes OP ya can grind after heat treat by dipping. What grinding equipment do you have?
You see the blade is already completed. I was thinking of reprofiling it to make the curved tanto into an american tanto
Seeing as how you're talking about the edge and tip, which are the thinnest parts of the blade and most prone to suffer from overheating, how about files? Depending on the hardness level, a new steel file might work. If the blade is too hard for a steel file, diamond files should work.
RokJok
Gold Member
- Joined
- Oct 6, 2000
- Messages
- 3,601
Since we love eye candy pictures around here, allow me to request a shot of this knife. Y'know, so we can see what you're working with.
Please, and thank you in advance. 
To make a rough first cut to "clip" the curve into a straight line up to the tip, a carbide grit blade in a hacksaw frame should be slow enough to avoid overheating. Frequent checking with your fingers to monitor temp is still judicious. It will, however, leave you with the task of creating bevels & an apexed edge on the triangular cross section of the new linear front portion of the blade.
Ancillary random question for the knifemakers: Is plunging into ice water (or pressing the flats of a warm ground blade against an ice block) to dissipate heat advantageous (i.e. more efficient) than dipping in cold tap water? Or is there a thermal shock danger from the temperature gradients getting too steep? My guess is no, but I'll defer to the pro's in the crowd. TIA.
I also have a question for the professional knifemakers:
Do you typically do your "rough out" grinding before or after quenching/hardening/tempering? I always assumed that it would be easiest to anneal/normalize the blade after the last forging session, then do your rough grind while the steel is softer, then quench/harden/temper after you get the blade close to its finished size and shape. The advantages of doing it that way (to me, anyway) are: You wouldn't consume as much grinding supplies, and you wouldn't have to worry about overheating the steel / changing the temper.
But it may be that trying to quench/harden a blade that is already thinned out is trickier due to possible warping/distortion, not to mention possible cracking. So I'm curious to hear how most of the pros do it. (Amateur blacksmith here, but haven't done much hardening/tempering, so it's still kind of a black-arts mystery to me.)
Last edited: