Are you experiencing any specific after installing custom models?

: C:\Program Files (x86)\Steam\steamapps\common\Half-Life\cstrike\

The Skeleton Knife is iconic for its minimalist, "skeletonized" tang design. In newer Counter-Strike games, it is praised for its unique handling animations, such as the 50/50 chance of twirling the knife when drawn or the rare infinite finger-spin inspect animation.

Start Counter-Strike 1.6 and load a local map or join a mod-compatible server to test the visual assets and animations. Community Legacy and Custom Servers

Use (or Jed’s Half-Life Model Viewer ) to open the Skeleton Knife .mdl file. Export the texture as a .bmp file.

(numbered 0 to 999), which controls the distribution of yellow, pink, and purple across the blade. 100% Full Fade

Launch CS 1.6. The knife should now display the gradient.

C:\Program Files (x86)\Steam\steamapps\common\Half-Life\cstrike\

The Ultimate Counter-Strike 1.6 Customization: How to Get the Skeleton Knife Gradient (Fade)