The SplineXS has an 8mm OD, which means the shaft fits into a standard 8mm ID bearing. This features allows teams to better support the end of the SplineXS shaft when the application demands it.
The SplineXS shaft on the Kraken X44 has a #10-32 tapped hole at the end, perfectly designed to fit the #10-32 x .250" L PHCS (WCP-1740) offered by WCP.
Use a combination of Kraken Spacers so that the pinion does not move on the SplineXS shaft.