Follow up to my problem with the arms on my 4.1 upgrade.
As previously posted the teeth on one of my spools (post 4.1 upgrade) got sheared and the other spools showed signs of stress on the teeth.
On disassembly it was obvious that the spools were binding on the arms and not due to foreign objects or due to belt guard interference.
During the subsequent rebuild of the machine I noticed that the fit of the new spools on the new arms was quite snug, but movement was smooth, so I completed the assembly.
To make a long story shorter… I am experiencing issues again and another disassembly show that the spools are starting to bind again.
I run my machine outside (under a canopy) and I am in Florida. I suspect that the temperature and humidity are causing the parts to expand.
I am now sanding/polishing the inside of the spools to get more clearance and see if that resolves the other issues.
Problem/solution is posted: Spool fix