How do you separate the machine expandable needles into 04 and 06

There is a difference in taper.

v04 and 06 taper difference is the taper is different. 04 machine expanding file taper is 04, while 06 machine expanding file taper is 06. root canal treatment instrument is also often referred to as "machine expanding", oral clinical use is very wide.

Machine expansion file endodontic instrument is also often referred to as "machine expansion", dental clinics are widely used.