The Dongtou Z3 expansion sets (JB-T7934-1999) http://www.wzlmjx.com/products_view.asp?id=1926 (1) expansion sets to host parts manufacturing and installation is simple. Install the expansion sleeve shaft and hole machining unlike the interference fit that requires high-precision manufacturing tolerances. Expansion sets installed without heating, cooling or pressure equipment, just the bolts required torque can be tightened. And easy to adjust, the wheel hub on the shaft to be easily adjusted to the desired position. Expansion sets can also be used to join parts of poor welding. (B) expansion sets long service life. (C) expansion sets will lose join role overload, to protect equipment from damage. Recommended products: expansion sets http://www.wzlmjx.com/