Weed trimmer brush attachment

I like your inventiveness, BUT those safety glasses aren't going to help when that thing comes apart.

Think about the amount of mass you added and the resultant extra forces that puts on the the head and the rest of the drive system.

It wasn't designed for that. If it is a one time short term use and you go careful you might get by with only slightly decreasing the lifespan of your trimmer. All other bets are off.

I am not the safety SS so I won't go there other than to encourage you to think through the consequences of catastrophic failure and prepare yourself accordingly. Keep your RPM's as low as possible to get the job done.

Weed trimmer brush attachment - video