Recently I was wondering what these two beautiful French instruments are used for.
At first I thought they were used to make threads on the lathe.
Browsing through an online store, I found this out by accident.
They are files for repairing threads on screws. As you can see on the side markings, on the lower one in metric measures is the pitch of the thread, on the upper one in inches with the number of turns per inch given.
I am very surprised by my new discovery.
At first I thought they were used to make threads on the lathe.
Browsing through an online store, I found this out by accident.
They are files for repairing threads on screws. As you can see on the side markings, on the lower one in metric measures is the pitch of the thread, on the upper one in inches with the number of turns per inch given.
I am very surprised by my new discovery.
