Backyard forging – Part 1: Setting your forge and Smithing a knife blank
Time and again people repeat that the single most important tool in bushcraft is the knife. That it is the one thing that you can’t do without.
So how easy is it to make this most important of tools and equip yourself with a functioning cutting edge?
I’m not going to beat about the bush, a knife made in this way isn’t going to produce the most beautiful professional product that you’ve ever seen, but this technique will enable you to end up with a knife that works, is perfectly suited to your needs and has been made by your own hands.
Best of all it will have cost you virtually nothing to make besides the investment of couple of days of time and a little elbow grease.
Over the coming weeks I will talk you through the process I have used to produce a knife. This will cover the following;
– Setting up a forge
– Hammering out a knife
– Profiling your knife and creating the bevel
– Tempering the blade
– Handling the knife
– Finally, that final safety component: producing a sheath.
Setting up the forge:
Our first consideration is what equipment you will need to set up our back yard forge.
You’ll be glad to know that all you will need can be found pretty cheaply and a fair amount will already be sitting gathering dust in either your shed or garage. If not, a trip to the local council tip will most likely sort you out.
The bare essentials:
The most charismatic component of the forging set up.
You’ll be glad to know that you don’t need to get a full size anvil, equipped with horn and all, to make a good knife. All you need to source is something hard metal and flat. I’ve purchased a square lump of railway track which weighs a tonne. A section of H girder would work just as fine.
The first knife I made was using an old cast iron shoe horn as the anvil which was looking the worst for wear at the end but managed to do the job for the day. Basically don’t get too hung up on it being the ‘right’ thing. As long as it’s hard and flat and reasonably strong it should fit the bill.
Open fires can work to forge small items like knives perfectly well but having something that contains the bed of coals and concentrates the heat is a great advantage and a more effective use of fuel.
A car wheel rim acts as my forge and so far there are no complaints. The hole in the centre allows for a direct air flow up into the coals should you wish to attach piping below.
For a simpler set up, and the one I’ve used to date is to direct the air flow in from the side.
A plentiful supply of oxygen is essential for forging and you will need to source a means of delivering it to the forge.
For my first knife I used a bamboo straw and nearly passed out from lack of oxygen so I wouldn’t recommend that!
A simply pair of hand bellows are cheap enough from your nearest hardware store should you not have some. For those preferring electrical aids acquiring the household hair dryer is the easiest way to blow life into the charcoal.
Tongs or pliers & thick leather welding gloves:
These are an essential few pieces of equipment that allow for careful manipulation of the metal while keeping you safe from burns.
Long handled tongs specifically designed for blacksmithing give you the advantage of holding the knife at a greater distance but ordinary needle nose pliers work fine. Make sure you wear the gloves at all times and NEVER be tempted to move the knife with your hands!
I say this because when starting out there is always the temptation to just quickly move it to where you need. The tongs take a little getting used to. Even with welding gloves on you’ll quickly find painful finger tips and useless gloves result from impatience.
Get used to using the pliers!
We are going to need something to beat our hot metal into shape so find a good, heavy but comfortable hammer.
I used a club hammer when doing mine but they can be fairly unbalanced. From my research, I’ve found there are a wide range of hammer designs for blacksmithing, each specifically designed for a purpose. Like I said before use what you have to begin with.
This is for removing impurities known as slag from the metal during the forging process as it forms on the surface. It will also be used during the profiling of the knife to clean the file of metal filings.
This can be any scrap length of metal that you have, a worn out round chainsaw file was good. It will allow you to manipulate the coals so that they are in the most useful configuration.
Two metal buckets or containers:
These will be required for the tempering process once the profiling of the knife has finished.
This can be a range of metal, all easily got hold of. Old files can be some of the best as these will be made from ‘Tool steel’ which has a high carbon content (1-1.25%). If you can’t get hold of any old files then I’ve found re-bar and even pig irons work well. These sections of iron might not have the specific qualities of a top rate knife but like I’ve said, it’ll work as a cutting edge.
Have a good rummage through old tool boxes or garage drawers as these often yield long forgotten files. Just make sure your Grandad isn’t looking!
SAFETY NOTE: It is essential that you have plenty water close to hand and a first aid kit in case of any accidents. Including burns cream!!!
For the set up above you can spend a small fortune on getting specifically designed blacksmithing tools that will do the job perfectly. I would never take anything away from this as they have all been developed over the years for specific jobs.
On the other hand the list above doesn’t include anything that is not found in most people’s tool kit and shed. What is missing can be found with a trip to a car boot sale or local dump.
First select your metal blank. As said above some metals are better that others but my first knife was from mild steel re-Bar and the knife keeps a tremendous edge and has proven itself to be extremely strong after a year and half’s abuse.
Through this series of blogs, the knife I show to completion is made from an old round file.
It is now time to get your forge lit and get the heat cranked up. Use a good mix of charcoal and well-seasoned hard woods. I found that this gave both the required heat while the hard woods had a longer burn time that the charcoal. This all allowed for a more prolonged burn time between restocking with charcoal.
The charcoal could be substituted for coal but I’ve so far had no experience of using it.
Arrange the forge so that the cords of wood concentrate the charcoal in the centre of the forge. This is the set up used during the whole firing of the forge. See picture above.
Heating and hammering:
After 20-30 minutes of good constant air flow the forge should be getting up to temperature where we can start to make metal hot. Place the end of the metal you intend to work into the centre of the forge where it is glowing orange and yellow.
Continue a good air flow so that the forge remains at a high temperature. As the metal turns orange or yellow you can removing it using your pliers and start to hammer out the profile. Make sure that the metal has turned from cherry red to orange or even yellow before you start hammering. From my experience if you start to hammer too early when it’s only light red the file will crack under the stress.
4. Tang being drawn out of file
Start first with elongating the tang of the knife to the required length. This is termed ‘drawing out the metal’ in the smithing world. Concentrate on forming a square profile and then alternate hammer strokes between the edges. Keep everything as flat and uniform as possible working as quickly as you can before the metal starts to cool.
This is your hand width plus 5-6cm to allow for comfort in use and the end to be riveted over to secure the handle. If in doubt as to what length of handle you’d like make it slightly on the long side as it can be trimmed off later on. See picture 4.
It’s always harder to add sections.
Aim for the tang to be 2-2.5mm wide and 5mm deep tapering towards the end. This again will depend on personal preference of knife thickness but I don’t like knives to be any thicker than 2.5mm, 3mm max.
Once you are happy with the dimensions of the tang it’s time to heat up the business end. If there is an excess of material then the first job will be to shorten the stock to a more workable length.
This is done by heating the point where the excess will be removed to as hot as possible and then hammer it at a 45° angle against the sharp edge of the anvil. This will shear off the excess and should leave you with a worked tang which has a short lump on the end.
This lump will now need to be drawn out the desired width of your knife. In my case, 2.5mm. See picture 5.
When trying this for the first time it can be difficult to judge how much stock you need left to end up with the correct length and width of blade. The second option open is to draw the whole remaining file out to the correct width and then shear off the excess after.
This is a more belt and braces approach as it prevents you ending up with a knife that is either too thin or too short. It can however mean a lot of wasted energy flattening a section that will be removed.
If choosing to shorten the stock before flattening, just use your best judgement on how much your need. I simply judge the current thickness and width compared to what I want and try to visualise how this will squash out.
Again, be conservative about what you’re taking off and remove excess afterwards.
5. Blade being drawn out of the stock
Having reached the desired length in tang and blade, heat the tip of the knife to yellow and placing it on the edge of your anvil, shear off what will be your cutting edge at a diagonal angle.
This is shown in pictures 6 & 7 and reduces a lot of profiling work that would otherwise have to be done in the next stage.
Heating the end of the knife again will allow you to hammer out the profile in greater detail, again reducing future work.
Just make sure that you are keeping everything flat by swapping hammer strokes between the ‘cutting edge’ and side profile of the knife. If you hammer too much on one edge it will end up folding.
This will not be a big job and doesn’t need a load of muscle. Light hammer strokes will suffice.
8-9. Showing forge being cranked up with hair dryer and knives cooling down from orange colour on Anvil
Once you have reached the stage where you are happy with your knife’s rough profile it is time to temper it to a low level of hardness.
This is done by getting the knife as hot as you possibly can and then taking it out of the forge and letting it air cool completely. This will result in the metal being soft so that it is easily removed with a metal working file.
Maintain an intense constant air flow to the coals once you have placed your knife in them. If you are unsure when to pull out the knife stop the air flow and pull it half way out. If the knife is only glowing red then try to get it hotter. Aim for light orange to yellow if possible.
This where my lungs had a good work out on my first attempt using a bamboo straw to blow down, I’d recommend the hair drier!
Once you’ve got the knife sufficiently glowing remove and place on the anvil. This will suck heat from the knife so it cools faster. DO NOT PLACE IN WATER. Do not be tempted to speed the process up by cooling in water as this will completely change the knife in ways we don’t want just yet. Just let it air cool.
The final step at this stage is to brush off any slag that might have formed again on the surface so give the cooling knife a good going over with the wire brush.
First stage complete:
Well done you have reached the stage where you deserve a well-earned cup of tea. So in true back yard bushcraft style, get the kettle over the forge.
Allow your knife to cool and show it off to everyone. If it is anything like when I first made one then your other half will expect you to come back inside with a strange looking lump of metal, not a knife-looking object!
Enjoy the praise and I’ll cover the material reduction and profiling in the next instalment.
- Pathfinder school video:
- The Real Wrought Iron Company
- Uddenholm temperature colour chart for tempering steel http://www.uddeholm.com/files/Temperature_guide.pdf