UBUHANZI
UBWIZA N'UBUZIMA
UBUKORIKORI
UMUCO N'AMATEKA
IMYIDAGADURO
IBIDUKIKIJE
IBIRIBWA N'IBINYOBWA
UBWUBATSI BUSUBIRA INYUMA
UBUMENYI
SIPORO
IKORANABUHANGA
IBYAMBARWA

Forged Cold Chisel
A cold chisel cuts cold metal, so its edge must be hard and its body tough. It is forged from octagonal tool steel: the head end is tapered, the blade drawn out at a yellow heat and finished with a flatter just above the hardening heat. Only the edge is hardened, by dipping it in water while the body stays hot, and the heat left in the body then tempers the edge; it is cooled when the edge shows blue tinged with red, about 570 °F (300 °C). The edge is ground to 60°.
Hagati
1–2 hours
Amabwiriza
1
1
Taper the head
Taper the head
Heat the head end to a yellow heat and taper it.
Ibikoresho by'iyi ntambwe:
Inkoni ifite impande umunani y'icyuma cy'ibikoresho1 igiceIbikoresho bikenewe:
Uruganda rw'umucuzi
Ingoyi
Inyundo yo Gucura
Amafashi y'umucuzi2
2
Forge the blade
Forge the blade
At a yellow heat, draw out the other end into the blade over the anvil's edge. Finish with a flatter just above the hardening heat; hammering it when black crushes the grain.
Ibikoresho bikenewe:
Igikoresho cy'umucuzi cyo kuringaniza
Inyundo yo Gucura
Ingoyi3
3
Cut and cool slowly
Cut and cool slowly
Cut the end square, or nick it and break it off after hardening to see the grain. Let the chisel cool slowly to relieve stresses from the forging.
Ibikoresho bikenewe:
Icyuma gikata gishyushye4
4
Harden the edge
Harden the edge
Reheat about 3 inches back from the edge, the edge kept high in the fire. Lower the edge into clean water at about 70 °F, moving it, until about half the heated part is under; plunge briefly and lift out with heat left in the body.
Ibikoresho bikenewe:
Uruganda rw'umucuzi
Indobo yo gukonjesha
Amafashi y'umucuzi5
5
Temper
Temper
Polish the edge and watch the colours run down to it. When the edge is blue tinged with red, cool the chisel completely.
Ibikoresho bikenewe:
Umwenda wa emeri
Indobo yo gukonjesha6
6
Grind
Grind
Grind the cutting edge to an angle of 60°.
Ibikoresho bikenewe:
Imashini ihyeza yo ku mezaIbikoresho
1- Umwanya
Ibikoresho bikenewe
9- Umwanya
- Umwanya
- Umwanya
- Umwanya
- Umwanya
- Umwanya
- Umwanya
- Umwanya
Iki gishushanyo gikora
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