What balls go on RJX servo arms?

[Dave Nelms]

The balls that came with my kit are 'M2x4', whatever that means. It also says (in the manual), 5x12mm and indeed when I hold the ball up to a ruler it looks to be nearly 5mm across and about 8mm long.

The linkage balls that came with my kit have a thread that is too large for the RJX servo arm, so I need the same size ball but a smaller thread.

The servo arms that came with my kit are perfect for the balls, but the spline is a tad loose on the RJX servo, resulting in play, whereas the RJX arm is quite snug.

I found a page full of balls on the RJX site but don't know which ones to use.

[deebee]

The m2x4 refers to the threads on the ball.. think of it like an M2X4 bolt with a 4.75 or 5mm ball for a head. If the threaded part is to thin then you will need a m2.5 or m3 thread. Too short and it will need to be x5 or 6mm long.
As far as the 5x12 not quite sure what that is referring to

I don't think I would use a ball with a thread smaller than m2 on a 700.
I bought a m2 and m2.5 thread tap each came with the proper size bit, just for the purpose of drilling, servo arms.

[Dave Nelms]

Many thanks - I'm slowly starting to figure this stuff out. That 450 sure was a cake-walk.