General Discussion

There are a few different types.

They often get a bit stuck in place

In a nut shell Most are spring loaded and it is very helpful to push straight down at the joint between the round post and the arm after you have loosened the set screw. With your other hand helping you can wiggle the whole assy. Up off the post while maintaining pressure on that joint to counter act the spring.

Some have a hidden set screw under the portion that attaches tobthe shaft. It's accessible by tilting the superficial cover