As mentioned earlier in this week I’ve been designing some boards on stripboard. The circuits are designed using wires to join the tracks and breaks to make a gaps in the circuit. This means you can use things like integrated circuits that have multiple pins on the same row and generally means that the circuits you create can be smaller.
Historically, I’ve used a drill bit to make these breaks. This is not ideal as it cuts away the board around the hole as well as removing the copper. This also weakens the board. Also using a drill bit in your fingers can give you cuts in your fingers so is far from idea.
So I decided to make a tool specifically for this job, a spot face cutter.
The shape of the spot face cutter is different to that of a drill. It has a small pilot pin in the middle and then a flat cutting face. Those that are designed for cutting stripboard also have a handle.
My starting material was an old bent drill bit. I used the bench grinder to put a large groove in this and then snapped off the longer end.
The next part was to grind on correct profile. This took me quite a few attempts. As the centre pin was just a few mm across.
To make the cutter cut, it needed some flutes. These were added using a small drill and grinding disk. After several tests and modifications, the cutter was capable of producing a round spot face, as seen on the right of the examples below.
The final step was to add a handle which was carved from a piece of branch from the garden and drilled to take the cutter. Once I was happy with it, it could be used for making circuits.