You can also throw one of these dampers on the arm to give your collective some smooth friction:

https://www.amazon.com/Whitecap-G-3140C-Nitrate-Gas-Spring/dp/B000FOUFGU/ref=zg_bs_16413861_10?_encoding=UTF8&psc=1&refRID=CTHYCZ2JGK9R4762ZZDB