I used arms that came with Hitec servos. The arms were long double ended,not star arms. I rotated arms to fit at 90 degrees as per manual setup instructions that came with Axe. Then cut off end of arm that was not needed. On these Hitec arms the outter holes are the same distance out as the OEM arms but I did have to drill them out to fit stock pushrods. Hitec arms are also too thick so I sanded the thickness of Hitec arms to .045 thick. Only sanded the ends where the pushrod connects so these Hitec arm are stronger. I had one arm that would not line up at 90 degrees so it is "down" just a tad. You can put OEM arms on Hitec servos but you have to push them on with force but they will go with enough elbow grease. I used Hitec arms because I could rotate arms on the spline and get my 90 degree angle. With OEM arms you can not rotate them because they only have one end to use so you are stuck with however they happen to fit for you. My next mod may be to make new pushrods and use ball links on servo arms instead of "Z" bend for attachment. Balls on Axe are 3.8mm and you can get them from Helihobby. I will check into this and see if there is enough room for this mod. Should take a little more slop out of system. BTW I have seen a pic of blade holders and flybar stabalizer that has had plastic balls removed and parts drilled out and had these metal 3.8mm balls installed. This mod has been said to stop the balls from breaking off these parts. One mod I have in mind is to drill and tap flybar stabalizer for a #2-56 set screw to lock flybar in place. The last crash I had the balls on flybar stabalizer were fine but the plastic bosses that the metal collars fit over sheared and allowed flybar to rotate. I ordered parts from Tower and they were on back order and I still don't have them. Lucky LHS just happened to get some and I bought two.