MacKINNON

Very common technique and one used a lot by Japanese smiths. As you suggest, it is to clean the metal surface of scale and can often be seen in the preparation of surfaces to be forge welded such as in 'Tanren' or fold refining of native Steels. As for not 'popping' , it will if the surface is concave and forms a gas trap when the hammer blow falls, but on blade size materials this generally isn't too much of a issue. The explosive 'pops' tend to occur at welding temps , not in the final forging range.

Love it !

I wonder why you lost so much weight ? Generally, I would not lose more than a few tens of grams on crucible steels.

Beautiful work.

A very intriguing finish. Many thanks for taking the time to document your process.

Nicw work, Mr. Richard

Another beautiful piece, Mr. Richard.

They are just mild steel and most guys make their own.

Outstanding !

You just keep making more and more beautiful things , Mr. Richard

When I was making folders I used a similar set up. I thought a mist lubricant system would be a good addition but never got around to setting one up.

I was looking forward to seeing this movie but I found it a bit of a let down. All the typical Japanese tropes and a cliched ending.

218 C is a hell of a hard temper on Carbon steels. OK, on differentially hardened blades but I wouldn't want to be bending a 1084 blade that hard.

Love it !

Have to agree with Mr. Zuiderwijk. Another thing to remember is leaf spring can be various grades of steel , some of which may be partially air hardening, so a slow cooling is always advisable before any cold work . Something like an AISI 5160 will be a little harder under than hammer than a 1060 or 1070 but they should still work easily at forging heats. Makes me wonder if you are trying to work the steels too cold.