Solid shaft collars are a "solid" construction and are generally fastened with one setscrew. The set screw has a knurled end that bites into the shaft, which is where the collar gets its holding power. The solid shaft collars are the most commonly used and are the most economical as far as price. Most solid shaft collars are manufactured from a mild carbon steel with zinc plating for corrosion resistance. You'll also find that some suppliers offer these in stainless steel or aluminum for special applications.

Pros:

Cost Effective

Simple Design

Cons:

Damages shafts from knurled setscrew

Difficult to remove based on location

Double split shaft collars are split in the center and fastened with two allen head cap scrcews. The double split shaft collars has greater holding power over the conventional style solid shaft collars. These collars allows for easier installation and replacement without the need of disassembling other components on the shaft

Pros:

Wont damage shaft

Increased holding power

Disassembly of shaft components not needed

Cons:

Can be expensive

Single split are similar to the solid collars except the single split has a higher holding power. This is achieved by torquing down the allen head cap screws, which allows the collar to pinch the shaft.

Pros:

Wont damage shaft

Increased holding power

Cons:

Can be expensive

Difficult to remove based on location