Before you use the above mentioned ball link sizing trick...may I suggest taking a pair of pliers and lightly sqeezing the ball with the serreated part of the pliers...all you need are some tiny grooves to help "mill" the inside of the link...a smooth ball could take days, weeks or months to size all the links on your heli! Also, use a vairible speed drill...no Dremel tools! Work slowly until you get the hang of it...1-2 seconds per link and then test fit should do nicely. Chris