Ferrule sizing, measuring and ordering instructions.
To measure the female. Take the smooth end of a drill bit and insert it into the female ferrule. Tell us the size of the drill bit in 64ths. The example below is a size 13/64th.

Using a fractional size drill gauge, insert the male end of the ferrule which would fit into the female into the gauge hole. That will tell you the size of the male ferrule. The example below is 13/64th.

Ferrule ordering instructions.
When ordering ferrules, please do the following to ensure correct style and size match:
Following these instructions will enable us to send you the correct ferrule the first time.