I've been trying to get a relic Chainsword & Rod with the enchant "5.0% to 10.0% chance on hit: All hits are guaranteed critical strikes for 3 seconds". 

Managed to get the enchant on all other weapons in a few rolls, but I've made more than 500 re-rolls on different chainsword & rods to no avail. Asking around, seems like nobody has ever seen that enchant on that type of weapon.

The blueprint crafts c_chainsword_rod_godlike

The enchant only rolls on  c_chainsword_rod

Might be it only rolls on dropped chainsword & rods, not crafted.