Transfer punches
Transfer punches are a very useful tool for marking through holes onto a surface. They are not expensive but one day I needed a 6 mm punch but did not have a set. I could have machined one up out of silver steel (drill rod) and then hardened and tempered it. However I came up with an alternative approach that was so successful that I made a set, as shown above.
I had some masonry nails lying around in the workshop that had been left over from a job. These are hardened nails for directly hammering into brickwork etc. These are very hard and impossible to file. The diameter of the nails was 3 mm. I chucked one of these nails in the chuck of a portable electric drill and quickly ground a 90 degree point on it by holding it up to the rotating grindstone of the bench grinder.
I then prepared a piece of 6 mm diameter mild steel rod by drilling a hole 3 mm diameter in the end for a depth of 12 mm. I cut of the pointed tip from the masonary nail using a Dremel type tool so that, when inserted in the hole in the 6 mm rod, the tip was just prodruding. The tip was fixed in place with epoxy resin.
This was so easy that I quickly made a set of punches with sizes 3. 4, 5, 6 8, and 10 mm
I had some masonry nails lying around in the workshop that had been left over from a job. These are hardened nails for directly hammering into brickwork etc. These are very hard and impossible to file. The diameter of the nails was 3 mm. I chucked one of these nails in the chuck of a portable electric drill and quickly ground a 90 degree point on it by holding it up to the rotating grindstone of the bench grinder.
I then prepared a piece of 6 mm diameter mild steel rod by drilling a hole 3 mm diameter in the end for a depth of 12 mm. I cut of the pointed tip from the masonary nail using a Dremel type tool so that, when inserted in the hole in the 6 mm rod, the tip was just prodruding. The tip was fixed in place with epoxy resin.
This was so easy that I quickly made a set of punches with sizes 3. 4, 5, 6 8, and 10 mm
This shows a close up of the tip of the 10 mm punch.
This set of punches covers the most common metric sizes. I have since made additional sizes for different jobs.