Forge and anvil
My workshop is in house that I built in Cholul in 2015. Cholul is a pueblo in the northern part of Merida. It was swallowed up by the city as it has grown. When doing quiet work I can hear the splashing of the pond outside the shop door and the singing of the birds that come to drink and bathe in it. Outside is a propane forge and the anvil I got from Jorge’s father (read more about the ANVIL) Inside are four large worktables – one clean for layout and design, drawing, etching and the fine fitting of folding knives; and the others not so clean. I have a couple of belt grinders, a 1940's vintage Atlas drill press, a small band saw and buffer. A heat treating furnace sits on it's own block stand. A cabinet at my main work table holds hand tools, and under each table and on the walls are shelves for supplies. I built the worktables more than thirty years ago from 4 x 4 and 2 x 4 lumber and six inch carriage bolts - strong, but able to be disassembled and moved when the need arose - it's been five moves now, including the last one to Mexico. There are lot's of windows and skylights that provide beautiful, even light during the day, so I only have need of incandescent lights at each workstation.
The Process
Checking thickness of folding knife blade
I make knives that are both forged from bar stock and ground from flat stock. For knives that are staying in Yucatan, I usually use stainless steel, as the heat, humidity and the salt air from the Gulf of Mexico cause a carbon steel knife to start discoloring almost immediately. For my own use, I like a knife that tarnishes and gracefully turns gray with age and thoughtful use and good care (like all of us do). So I will gladly use carbon steel for your knife, if you'd like.
The bars of steel are cut to size on the band saw, and if forged, are heated in a propane forge and rough shaped on the anvil. The profiles of the roughly formed blades are refined on one of the belt grinders, and by hand with a variety of files. Then the blade bevels are ground with a flat, hollow or convex grind. For folding knives a spring must be shaped and then hand fit to the blade, making sure that they line up properly in both the opened and closed positions.
The bars of steel are cut to size on the band saw, and if forged, are heated in a propane forge and rough shaped on the anvil. The profiles of the roughly formed blades are refined on one of the belt grinders, and by hand with a variety of files. Then the blade bevels are ground with a flat, hollow or convex grind. For folding knives a spring must be shaped and then hand fit to the blade, making sure that they line up properly in both the opened and closed positions.
Trial fit-up of Small Folder
The rough ground blades and springs now undergo a heat treatment process. This is where they are transformed from knife-shaped pieces of steel into knives. Prior to heat treatment, being in an annealed state, the steel is relatively soft. It could be sharpened, but would quickly loose its edge, and would bend easily and not spring back to shape. Forged blades first go through a triple normalization process that refines the grain and relieves the stresses that were forged into them. The heat treating process involves raising the temperature of the steel above it’s critical temperature, between 1450 and 1900 degrees F, allowing it to soak there for a specific time, and then quenching the steel in oil or air in order to rapidly drop the temperature and harden the blade. After quenching, the steel is at its maximum hardness – brittle enough, in fact, that it might shatter if dropped. So the hardened steel must now be tempered – heated and soaked again, but at a much lower temperature, between 300 and 500 degrees F. The blades are at a useable hardness now - which is always a compromise between the extremes of maximum edge holding hardness, and tough but bendable softness.
Workshop Espresso
The stainless blades and springs are hardened in the electric furnace where temperatures can be accurately controlled for the required fifteen-minute soak time, and the atmosphere can be controlled. They are then air quenched between two thick aluminum plates. The carbon steels are hardened in the forge and quenched in oil. The carbon steel blades can also be selectively hardened and tempered so that the edges are hard, the centers more spring like and the backs and tangs softer and tougher.
Fling and carving back of blade
The heat-treated blades are now finish ground and polished, first using the belt grinders and hand held polishing stones, then abrasive papers and buffs. The blades and springs of folding knives are again hand fit and polished to insure proper alignment, smooth opening and closing and proper spring tension.
Handle material is chosen, usually local tropical hardwood or horn, roughly shaped and then glued and pinned in place. The heads of the pins, or rivets, that hold the knives together are peined in place and left proud of the handles to insure they stay secure. They are left with the hammer marks to show the work of the hands that fashioned them.
Folding knives all have a coin silver escutcheon on the mark side of the handle. I make the escutcheons from old silver coins – usually silver Mexican 10 centavos from the late 1800's or early 19oo’s, but occasionally US silver mercury dimes. I buy the coins at the Sunday flea market in Santa Lucia square, then hammer them flat and shape them with needle files. I can engrave initials in the silver, or I can etch initials, a date or inscription on the blade. (see options here)
Kitchen knives are fitted with a fabric covered cardboard sleeve to protect the sharp edge (and your hands). This sleeve is just for travel and not meant for permanent storage. For folding knives I make a leather pouch from local leather. Hunting knives come with a heavy leather sheath wet formed to the knife and finished with a mixture of beeswax and oil. Knives should not be stored in leather for long periods though, as the acids used in the tanning process can stain the blades.
Handle material is chosen, usually local tropical hardwood or horn, roughly shaped and then glued and pinned in place. The heads of the pins, or rivets, that hold the knives together are peined in place and left proud of the handles to insure they stay secure. They are left with the hammer marks to show the work of the hands that fashioned them.
Folding knives all have a coin silver escutcheon on the mark side of the handle. I make the escutcheons from old silver coins – usually silver Mexican 10 centavos from the late 1800's or early 19oo’s, but occasionally US silver mercury dimes. I buy the coins at the Sunday flea market in Santa Lucia square, then hammer them flat and shape them with needle files. I can engrave initials in the silver, or I can etch initials, a date or inscription on the blade. (see options here)
Kitchen knives are fitted with a fabric covered cardboard sleeve to protect the sharp edge (and your hands). This sleeve is just for travel and not meant for permanent storage. For folding knives I make a leather pouch from local leather. Hunting knives come with a heavy leather sheath wet formed to the knife and finished with a mixture of beeswax and oil. Knives should not be stored in leather for long periods though, as the acids used in the tanning process can stain the blades.
