The Mad Ramblings of a Blacksmith: Punching a hole

Today we were given a demo about punching a hole into metal.

This is just a quick run through using a punch to help.

Before punching your metal it is advisable to check your punch over to see it is straight and has a sharp corner on the bottom, while using they are prone to bending off center.
If your punch is off center then you will need to get it back center, normally this would be easy but this isnt your common steel, punches are made out of a Mild steel which works at different temperatures to common steel.
First the maxium heat you can work on a punch is a bright orange no higher, it can not be worked cold because it will just shatter straight away. While working on it never clench it, when your doing with the next steps leave it to cool down naturally.
Start by hammering it square then knocking the corners off, work it down to a octogon shape, make sure it is even all the way round. One off corner and it will show in the punch.
After hammerng it round you want to heat again and hamme the end of the punch flat, make sure there is a sharp corner around the flat this is essentail.

After this you should be ready to get going on punching, here is a quick step by step guide to good

punching pratice.

First off center punch where you are going to making the hole just for good referance.
Make sure there is a good heat across where your going to be punching, if it is too cold then it will drag metal from around the hole in with it making a deep depression in the metal, you dont want this.
Strike down at a 90% degree angle, if you go over you will have a hole that goes one way more. You can change the direction of a punch half way through the metal but this is very difficult.
Constantly wire bursh your work so you can keep tracks on the hole.
Give really heavy blows to get into the hole quick before the heat goes, once you feel the anvil begin to kick back you are far enough to flip it over
There will be a very clear shadow on the other side, line it up and hammer into this mark
Hammer over the pritchel when you start on the back because as you suddenly break through to the other side your tool will whack into the anvil damaging the anvil and the punch.
Working both sides of the hole is essentail to get an acurate hole right through it.

Follow these steps and you should be have yourself a pretty good hole.

A few very helpful tips i was given after the demo.

Make sure to constantly clench the punch when your working it in the hole, if you dont it will become hot and begin to expand if this happens while it is in your work it will become stuck and its quite embarssing.
When your straightening you can work it cold but only with very gentle blows this is only really if your taking a small bend out of it, anything more and you should heat it up.

Here are a few pictures of punched holes.