How to Make a pinhole for a Pinhole camera

There is much information on the web for making pinhole cameras but nothing I have found in great detail for making the actual pinhole accurately.

I hope that this small web site helps to show you how I  make "the pinhole".
What you require
The first requirement is a good accurate Digital Caliper without which you are unlikely to make the size pinhole you desire.
The second item is a good sharp needle with a long thin pin and a diameter about 2x the size of the hole you wish to make.
The third item is a good pencil rubber which can be cut into about a 10mm cube.
The forth item is a ball point pen
The fifth item is some 400 grit wet and dry paper.
The sixth item is a piece of "fizzy drink's " can cut to the width of the holding slot of your pinhole camera.
The seventh item is a piece of card
The process
Place the drink's can metal on top of the piece of card and press the ball point pen lightly onto the metal.

If you press too hard then the next process will make an immediate hole through the metal and too lightly and you will not be able to locate the depression.

The first photo shows the depression and the second photo shows the pimple developed on the other side.
With the depression made place the pimple side on the 400 grit wet and dry and gently move in a circular motion until the pimple has been removed. The drink's can metal thickness will now be much thinner at the location of the pimple than the rest of it. Place the metal to one side.
Having done the calculation for the size of the pinhole you require set the caliper to that dimension, I use diameter of pin hole = 1/25 x the square root of the focal length.

Press the needle through the piece of rubber, which is about 10mm x 10mm square, until the projecting part is the width of the calipers. Double check by loosening off the caliper and measuring in the normal way, adjust as needed until you are happy the projection part of the needle's point at the surface of the rubber is the dimension you require your pinhole.

The diameter of the needle, in the photo,  at the rubber surface is 0.28mm as required for a camera I am making.
Recover the piece of metal and very gently press the pin of the needle into the hollow formed by the ball point pen until you just feel it pierce the metal. Remove the needle.

Return to the 400 grit and gently remove the burr that will have developed.
Now the burr has been removed, or so it looks but see the photo below.
Place the needle into the little hole and with a circular motion push the needle a little further through the metal. Then again remove the burrs and continue these actions until the needle is through the metal and laying flush with the rubber. Then turn the metal over and push the needle into the hole with a circular action until it again touches the rubber. Remove and burr that may have developed.

Note that the picture shows a hole where the burrs have been flattened and ended up back inside the hole so application of the needle in the hole is needed and then follow with the wet and dry.

You should now have a circular hole - due to the circular action of the needle and no burrs - you hope !!!
Check the accuracy of the hole with a magnifying glass and if poor start all over again.
The better you make the hole the better will be your results in pinhole photography.