As mentioned before, the factory design is to have one end knurled, so that the fit is semi-permanent.
To make it easier to split the tracks in the field, or to temporarily replace links, I decided to make up some custom track pins.
These are 5mm stainless steel, with a V groove cut in the centre. The stock grub screw is replaced with a pointy ended one
The link is held securely in place by the interlocking action of the end of the grub screw and the groove in the pin, rather than just the pressure of the grub screw. This also means there's need temptation to over tighten the screw, and so no risk of damage to the thread in the track link. A drop of red Loctite should prevent the grub screw coming loose but it will still be removable if needed.
I've drilled the ends to 2.5mm and will see if I can tap them M3. That way an HT screw can be inserted so the pin can be pulled out.
The holes also act as indicators of which pins are removable.
Adrian.