Genno
Gennō ( Japanese 玄 翁 and 玄 能 , gennō ) is a Japanese form of hammer with flattened sides. The Gennō is universally used in woodworking , e.g. B. for hammering nails , for fitting and adjustment work, for hammering chisels , for inlay work, etc.
There are different head shapes in the Gennō, whereby the two ends are essentially flat ( ryokoguchi ). The cross-section can be circular, oval, rectangular ( 4-Kaku-Gennō ) or octagonal ( 8-Kaku-Gennō , e.g. for setting the plane iron on the Kanna (plane) ). Depending on the application, hammers of different sizes are used:
| Surname | typical weight |
|---|---|
| Tokudai-Gennō ( 特大 玄 翁 , extra large Gennō) | 940-1125 g |
| Ō-Gennō ( 大 玄 翁 , great Gennō) | 650-750 g |
| Chū-Gennō ( 中 玄 翁 , middle Gennō) | 400-500 g |
| Shō-Gennō or Ko-Gennō ( 小 玄 翁 , little Gennō) | 250-300 g |
| Mame-Gennō ( 豆 玄 翁 , Mini-Gennō) | 100-150 g |
In the case of smaller Gennō shapes, one of the two striking surfaces is slightly convex so that the nail head can be easily countersunk when the nail is hammered in with the last blow without leaving any traces of impact on the wood surface. The heavier hammers have two completely flat striking surfaces. The hammer heads are usually made of soft iron with carburized and then hardened striking surfaces or with forged ( fire-welded ) striking surfaces made of hardened steel .
A 375 g heavy gennō is usually used to strike the Japanese chisels ( 鑿 , Nomi ).
Sources and further reading
- Toshio Odate: Japanese Woodworking Tools: Their Tradition, Spirit, and Use . Linden Publishing Co Inc., US, ISBN 0-941936-46-5