San Mai construction

A question for you forgers. (is that right?) When you make a San Mai knife, do you start with three pieces of steel with the hard steel in the center and forge weld it and hammer it down to the proper thickness to be turned into a knife blade? If so, how when you start with say a sandwich an inch or more thick, do you keep the center in the center and the side steels a uniform thickness? Does it take care of it, itself, or is that one more thing that can go wrong?

 

yes.
i do : 6mm , hi carbon steel in the middle and 8mm in each side .

 

Three pieces, 5... Depends on thickness, and how long the billet required. May need mor steel, than one piece will allow. As for centering, yes, for the most part, all things being equal, the core will center. Now that being said, the core may have a wave to it from multiple hammer blows of let's say un even impact energy. To be certain of a perfectly straight core, some better equipped smiths will use a roller mill. Even pressure to draw out the billet. Others will grind the edge, then etch to better see the core, straighten the core visually, then grind the billet/knife. To keep the exposure of the core even, occasional light etching to check progress is helpful. No such thing as too many checks! Ask me how I know!

 

Mike do you have some anvil envy we should know about.

 

I start with three layers. The important thing is that the two outside layers are the same thickness to start. Even forging keeps the middle layer centered. I use a press with flat dies and a power hammer with flat dies to make sure that happens.

 

thanks guys.

Jim in a nutshell,,,, Heck yeah. I have the opportunity to get a family anvil. But it is big and not sure I want to go down that road.

 

This, absolutely.

Also, 'forging evenly' means flipping the work regularly so you're striking both sides with the same number of strokes, and hopefully the same force. If you do not flip sides, the hammer side will thin more quickly than the anvil side, moving the core off center.

There is NEVER such a thing as 'too big' an anvil, lol. Mass under the hammer is what makes an anvil work. This is why my anvil is a post. 240lbs or so directly under my hammer at all times. No horn, no table. Just flat working surface goodness! A post anvil like mine works as well as a traditional anvil three times its weight.

 

Good question and great answers. Really enjoying info like this.

 

Great thread! Some good info here thanks guys. This is so timely for me to read as it answers something I've been struggling with thanks