Saturday, July 16, 2016

Forging a Sword Blade

Ongoing commission, filmed July 15, 2016.

Working with patterned dies on a 50 lb air hammer.
This is a matched pair of dies contoured to create a roughly 2 1/4 inch wide simple diamond cross section, set up with a folded spring. The dies fit into a 'hardie' attachment that itself bolts to the bottom die of the air hammer.
(The air hammer was the first model built by David Robertson - about 15 years ago.)

Material being forged is middle carbon spring steel, the source is a (new) spring harrow tooth.
The starting dimension of that material was roughly 5/8 x 1 inch, curved to a half circle. This has been initially flattened, then forged to a starting profile as seen here at roughly 7/32 x 1 3/4 flat.

Each section of 4 inches requires roughly 6 passes like the ones seen here to create the (very) rough forged blade profile. As the blade is lengthened, it is important to ensure the centre line is kept as straight as possible. (Wavering in the edges is expected at the rough forged state.)

Once completed, the edges will be carefully forged to create ensure a minimum width to the blade, in this case 2 inches (plus?). Also a consistent thickness at the edges will be created. This may result in some bulges, but those will be ground out to made an even profile.

At the point seen in the video, about 20 inches of the required 32 inch finished blade have been rough forged. As can be seen, there is considerably more material available on the source bar than will be required for the finished sword.
The design calls for a short riccasso (unsharpened) section at the base of the blade. With this measurement established, the shoulder leading into the tang will be made, and the tang forged to the required length.

1 comment:

David Robertson said...

The Specialty pattern dies really speed up the process of shaping the uniform diamond for the sword. I am sure other die configurations could be created such as top and bottom fuller.


February 15 - May 15, 2012 : Supported by a Crafts Projects - Creation and Development Grant

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