Forging Mokume Gane

[Patrick Nowak]

For quite a while most of my forge time has been spent forging mokume billets into bars stock and I thought many of you might find the process interesting. I've posted a series of photographs (see embedded link to photobucket) showing the process of forging a 0.210" thick x 1.375" wide bar of twisted material from a staring size of 1"x2"x6". The final bar is about 36" long. The process typically takes about 8 heats and is as follows:

1. Forge initial billet to 0.700" square.
2. Forge to 0.700" octagon
3. Twist
4. Forge to final size.

Steps 1&2 take a total of 3 heats, twisting takes an additional 3 heats to ensure even twists to the end of the bar and forging the twisted bar to final size typically takes 2 more heats. This bar is machined to a final size of 1.00" wide x 0.135" thick and is used by production knife companies for high end folders. My part of the process is to do the forging. Fusing of the starting components and machining is handled by my customer, who then supplies the end users. The billet shown is made from 89 layers of copper, brass and nickel silver. Typical forging temperature on this material is 1800F down to black. Besides the obvious risk of overheating, the two other main concerns are preventing delamination due to poor forging technique and making sure to achieve the full 1.375" width, which is also a function of proper forging technique. The die pictured allows me to forge a variety of widths but all to a thickness of 0.210". The hammer used is a 300# Bradley Guided helve. This is an application where the long dies of a Bradley are very well suited to multi-size production tooling. I have similar dies for forging 3/8" thick by 2.500-2.625" widths which are the starting sizes for raindrop and ladder pattern material. When forging these sizes, the starting billet is 2x2x6.

One of the most interesting mokume projects that I've had a chance to work on was the forging of billets for cell phones. These were all machined from solid blocks 5/8" thick x 2" wide. I was able to attach one here. You can find additional pictures and information about the company making and selling these phones by doing a web search on the topic.

http://s1126.photobucket.com/albums/l617/pnowak1/

Patrick

[Rich Hale]

Do you do the initial weld on these billets?

[Patrick Nowak]

Nope,

The initial bond is made in an electrick kiln with the piecies clamped between two steel plates. When I get them they are already a solid block.