One of the JR 215 heavy duty nylon arms stripped the splines on my KingCat flap a couple of times.........they were supplied with the 8611 servos, just the same as the 8711's than Sean showed in his post.

I bought some of the same part number arms once, only to find that they were the standard duty arms that had been mislabeled. Every bag in the model shop was the same.......
I have switched to the metal arms from Jetpower and Hangar 9 wherever practical.

SWB clamping arms are too thick to use with a clevis, and the threaded holes are too large for a 4-40 clevis pin, which would make them sloppy even if you machined the thickness down to accept a clevis. I haven't seen any arms from SWB that are thin enough with 4-40 clevis pin sized holes.
Do they make such a thing?

Until they do, I'll stay with Hangar 9 and Jetpower machined aluminum arms.

Harley Condra
BVM REP
JetCat REP