Making a Knife
In making a blade there are many steps. Here I would like to show the steps that make custom knives different from cheap imported blades.
- Making a custom blade starts with the idea, a bunch of drawings and tests. What will the blade be used for? What style will it be? Handle, full tang or not? How large? These are the questions asked when designing. If it is a chopper, a longer blade, a large belly and blade heavy weight is wanted for the best chopping force. If it is a skinner, a smaller and more nimble the blade should be for precise cuts.
- What sets custom blades off from others most is the steel choice and heat treatment. The choice of steel mostly depends on the blades use or size. If it is a large blade or a thick axe or sword style blade, a lower carbon steel like 1055 is used. Other, smaller blades may use higher carbon steels like 1075-1084 or 1095. If stainless is desired, 440c or s35vn can be used.
- After the bladesmith is satisfied with a design, he cuts the blade out if his steel choice. This is hand done with a grinder and sander until the desired shape is made. This may also be done by forging on an anvil. There are many different blade shapes but the most common are typical curved edge blades, double edged and tanto.
- Then grinding or bevel forging begins. This is done by hand on a belt sander when a knife is done by stock removal. When the blade is forged the edge is thinned and drawn out until it is near the desired shape and then smoothed on the grinder. The bladesmith uses different grits and grind styles to hone to perfection. It may be flat, saber or hollow ground.
- After the initial grind or forging is done, (the final cutting edge or 'secondary grind' is done later) heat treating begins. If it is needed, normalizing is the first step of the treatment. Normalizing aligns the grain structure of the steel and prevents warping in the quench. Then the quench. The steel is brought up to 1450*F-1600*F or past critical temperature. To know if the steel is at critical the bladesmith checks the steel with a magnet. The magnet will cease to attract to the steel when it is at the critical temp. Then the steel is heated up a little more because past critical is desired. Then the blade is quenched in oil and cools from about 1500*F to 100*-120*F. This rapid cooling makes the steel extremely hard. In fact brittle, too hard to be used as it can shatter if dropped or hit. To soften the steel slightly and release the strain from quenching the steel is then tempered. This is heating at a lower temperature, around 400*F, and air cooling.
- The blade is then ready for an edge. The edge is ground with a high grit zirconium belt and then buffed with compound and stropped for a dangerously razor sharp edge. If a more "toothy" edge is desired, a 220 grit belt is used and then edge is stropped.
- The handle is then placed on the knife. Many different materials are used for handles the most common being wood, bone, G-10 and micarta. It is held with pins and then glued with high strength 2-part epoxy. The handle material is then hand sanded to feel good in the hand and provide grip. The last step is oiling the handle to give is a superb finish. The blade is now ready for whatever task can be thrown at it.
- To carry and protect the finished blades a sheath is then hand made. Whether is it quality leather or kydex, the sheath is made for the specific blade it will be carrying.
Clearing things up.
Yes, all of the terms get quite confusing especially if you are just learning of this stuff.
Tang. The tang is the part the metal piece that is below the blade in the handle part. A full tang handle is when the steel runs the whole length and width of the handle. The pieces of wood material called 'scales' are held on with pins, tubes and glue. A partial tang or 'push tang' is when the tang is about half the width of the handle and is pushed into drilled holes in the handle material.
Different grinds. there are three different grind styles, flat, saber and hollow. Flat is when the whole face of the blade is a wedge shape from the spine to the edge. Saber is ground a bit lower than the spine. Hollow grinding is done with a wheel rather than a flat platen to give a concave or 'hollow' grind.
4. Blade types. There are a few different types of blades. It varies by their shape and swedge. The swedge is the false edge on the back of the blade. The swedge improves the sharpness of the tip resulting in extreme stabbing power. Clip points are named by their 'clipped off' appearance. They are shaped to look as if the back of the blade was clipped and then a swedge is ground. Bowies are made with this point. The spear point sometimes is used to describe double edged blades but also is like the image shown. It is like the clip point but the swedge is curved towards the tip rather than straight or curved inwards. The tanto point is a very functional blade type. The shape allows the spine to run closer to the tip than other tip styles which prevents the tip breaking. The angle rather than curve gives the blade an additional point which makes it deadly in flat slashes. The tanto point is often seen with a swedge as well. The drop point has a large belly (curve towards tip) which makes it great for chopping but provides a less-swift stab. It is called a drop point because the point is 'dropped' or curved down but without a swedge.