This is my dad's Ever-Ready C-40 that he got back in the 70s when he was a teenager I had my mom sneak it to my house and I fully restored it. Polished the handle, drilled out and slightly enlarged the opening with a rotary tool to accommodate the 22mm synthetic knot. I then weighted the handle a bit using coins and epoxy to hold them in place. All that was left to do after that was place the new knot and let the epoxy adhere! I gifted it to him last night and he could not have been more thrilled! I also have a c40 that I got off of ebay and restored so father and son now have matching brushes.