I thought we should have a go at making a crowbar, it is relatively simple to make and shows a couple of basic techniques.

First of all, the safety stuff. It is advisable to wear goggles and gloves, I don’t, but I can assure you it is painful when you get your eyelids stuck together with a piece of red hot scale.

Now that’s said we can get on to the interesting bit.

First we have to select some steel, medium carbon steel is best for this type of work, normal mild steel is too soft and would just bend when any load was put on it, and high carbon steel is a little hard and if not treated correctly it is liable to crack and break. So medium carbon offers the best option, allowing for enough hardness as to prevent heavy wear but is resilient enough to resist bending.

If you have bits of old steel laying about here are some simple tests to help you test it’s hardness the first is to grind some and look at the sparks, if they are mostly dull orange with a few white sparkles then it is probably mild steel, the more white sparkles the higher the carbon content the harder the steel see fig 2.

Another test is to drop the steel on the concrete floor, a dull thud = mild steel, the higher the pitch the harder the steel.

You will need a piece of steel about 750mm long and 20mm in diameter. Heat the end for about 40mm to a yellow heat this is about 1,100 deg C, 2,000 deg F (a bit warm). If you have a forge you should place it in the fire as shown in the diagram, to low in the fire and the air causes the steel to oxidize and scale up, to high in the fire and it won’t heat up properly and it will be harder to work.

Place the end of the steel at the edge of the anvil (this can be any heavy piece of steel with a flat top) raise the end you are holding to an angle of about 10 deg, and with your hammer angled at about the same start to forge the end down into a taper. This is called drawing down.

As the taper gets longer you will notice that it also starts to widen you don’t want to have too wide so you can control this by turning 90 deg so as it is on it’s edge and gently forge the edges back in slightly, turning through 180 deg and repeating as the hammered side always moves more than the side on the anvil. This will even everything up.

Make this taper quite long and thin as this is the end that will be used to extract nails, so it has to go under the nail head.
Heat the end again taking care not to overheat the thin end, and with a cold chisel cut straight across cutting off the rounded end.
Let it cool down. Once cool mark the centre with a centre punch measure back about 35mm and mark the centre with another punch mark. These marks the steel so it can be seen when red hot. Take a heat and split between the two marks with a cold chisel quenching the chisel every couple of blows so as not to remove the chisels temper.
Take another heat and open the split out into a vee with the chisel.

Repeat the drawing down on the other end with some differences. First make a small taper on the sides, this helps to control the spreading as you need to keep this end narrower and more robust because this is the pinch bar end and it needs to have more grunt.

The bending can be done in two ways, but first on the nail pulling end put a centre dot 100mm from the end and heat to yellow evenly for about 30mm each side of the dot.
When this is done it is time to bend, way one is to place the on a steel bar or robust pipe and strike the bar with a hammer at the thick end of the taper so as not to damage the split part see diagram, bend about 135deg.

The second way uses the same heat technique, but this way you place two steel bars/pipes in a vice place the heated between the bars and pull to the required angle.
The pinch bar end is done in the same way, but mark the length at about 50mm, and bend to about 30deg, remembering to bend it in the opposite direction to the other end.


Now we come to the most difficult area, hardening and tempering, this is where you harden the steel to its hardest possible state and then soften to its required hardness/resilience. As this tool does not need to be ‘hard’ but has to be able to resist bending, it needs to tempered back to a dark blue oxide colour, which offers a certain amount of springiness
Here’s how you do it. The easiest way for a beginner to do this is to harden and temper separately.
First heat each tapered end too a cherry red heat, this is about 750deg C or 1,400deg F you can test if it’s over 700deg C as at that temperature iron is no longer magnetic.
With a steady movement put the steel into cold water and keep it moving (this stops the possibility of a hard line forming which may cause a fracture under load).
Clean up one side with some emery cloth, old grindstone or file to remove any scale and leave a bare metal finish, this is so you will be able to see the tempering colours as they appear on the surface.
If you have a blowtorch or the such gently heat the steel from just behind the point to which you hardened, don’t do this in direct sunlight or you won’t see the colours.
You will now see colours appearing starting with a light straw colour progressing trough various straws, brown, purple and blues, the colour you are looking for is dark blue, once you have reached this colour down to the tip, plunge it into water until cold.

If you have any queries or you need more information please let me know, and if there is a particular project you want, tell me and I will see what I can do.

Gordon

This recipe was submitted by Ironworker