Annealing on a grinder?

DeadboxHero

DeadboxHero

Knifemaker / Craftsman / Service Provider
Joined
Mar 22, 2014
Messages
5,512
I watch a special on Finnish knife making of puukos.

He quenchs in water, then grinds away the stress on a big wet clay wheel. They grind the primary and get the blade to a tan or blusish hue. Then lets it cool to room temperature.


My quetion for the heads is what's going on here?

How does this compare to parks quench oil and a digital heat treat oven?

Thanks guys
 
Many old time grinders in Germany and Scandinavia fully water quenched their simple medium carbon steel blades and then did the bevels on a large wet wheel. They watched the colors and finished at a straw to blue color. This was a simplified method of tempering ( not annealing). In German, the grinding machine was called the "Der Blaupliester" ( something like "The Big Blue Grinder").

The metal does not get properly tempered, and stress is only minorly relieved. Mostly, it prevents edge chipping.

It isn't nearly as good as a proper HT with oven tempering.
 
Great video. Very cool ... Lots of metallurgical misinformation, though.
 
I don't understand why you are under the impression that the blade was tempered at the grinder. The video showed the tempering on a pan over the charcoal
 
Indeed. But he makes sure to heat it on the grinder first to a specific range of temperature by the color of the steel.
 
Remember that in the old days steels were very simple and techniques were simple . Modern steels require more precise control of temperature .
 
Great old vid, I love watching the old craftsmen even if we don't always agree with how they did it..You know I have a lot of old tools made with methods like that, they have been working just fine for 100 years..
 
The "blue at the grinder" (water cooled grinder btw) is a way to describe the hue developed by the steel's surface due to light refraction on the fine grinding marks.
die blaupliesten has been explained on hypefreeblades by Roman Landes. Tempering is the next step, on the charcoal fire.
The video you posted is very interesting, i love this kind of vintage working process, thank you for sharing :thumbup:
 
Last edited:
Stacy E. Apelt - Bladesmith said:
Many old time grinders in Germany and Scandinavia fully water quenched their simple medium carbon steel blades and then did the bevels on a large wet wheel. They watched the colors and finished at a straw to blue color. This was a simplified method of tempering ( not annealing). In German, the grinding machine was called the "Der Blaupliester" ( something like "The Big Blue Grinder").

The metal does not get properly tempered, and stress is only minorly relieved. Mostly, it prevents edge chipping.

It isn't nearly as good as a proper HT with oven tempering.
Click to expand...

I always look forward to your comments. I always learn something new.

cheers

grumpy_grinder
 
I watched that video...nice !

The "tempering" they refer to after forging we would call a quench. They are using simple steels and do an interrupted type quench that somewhat auto-tempers. That plus "removal of stress" on the hot pan ( tempering) makes an edge that holds up well and a softer spine.
 
Last edited:
There seems to be confusion caused by the narration. The quenched blades are ground bright on the grinder, before being tempered on the pan over the forge. When tempering by colors you have to make the blade shiny some how to see the oxidation colors. Stezann thanks for the explanation of die blaupliesten, I will look for that refraction next time.
 
Stacy, Stazann, CarcaraThanks for the explanations guys.

I watched the video a few times and was completly enchanted.

Pure Art.
 
You must log in or register to reply here.
Back
Top