Kydex sheaths? They were a fickle bi#%h for me to make. The material is very easy to work with, and easy to make a great looking sheath for most anything. The set up is next to nothing unless you plan to go big scale production. Temperature is the learning curve, Lots of fasteners out there to make easy work on assembly and belt attachments available too. It was as much fun to make as the knife itself.
The DOWNSIDE for me was I was making knifes that were more show, and less go. I could not get a sheath to not scratch the blades. In hindsight I never tried wrapping blades more to make a buffer zone between blade and sheath. If your not worried about scratching the blade they are very easy to make, lots of u tube videos,
Just found this one, he addresses the scratch problem, I wish I saw this 15 years ago