Paint brushes don’t do much actual painting in my workshop; most of the time they are used for clean-up. For the delicate jobs like cleaning drill and router motors I will leave the bristles long.
When I need something a little stiffer for the caked-on pitch on saw blades, I will cut the bristles down.
The closer you cut the bristles to the furrel, the stiffer the brush becomes and it really does a job on stubborn, hard to remove dirt and grime.
The longer bristled brushes do well for cleaning up my table saw threads on the lift and tilt mechanism, and my bandsaw wheels and guides.
In the fall before I fire up my 1500 watt convection heater, I take it all apart and clean all the dust that has accumulated on the delicate heating fins with the long soft bristled brush. This is a safety precaution to reduce the chance of fire.
Here’s the kicker:
None of these brushes are expensive and most of them have been discarded by my wife, who does all the painting. If she deems them unfit by her standards for whatever reason, they find their way to my shop, where I put them to good use.