flsun3D x carriage wheel tightener

I wanted to tighten the X carriage wheels on the flsun 3D

here is my proposal.

The 2 wheels on the hot end side uses longer M5 screws

The other 2 wheels are used in factory design, the tightener go over the nut.

The two parts are tightened using a M5 screw and a nut.