Originally Posted by GeoKrpan

The male notch in the part that mounts between between the frame and the shifter is a different width on Sunrace DT shifters than on Shimano DT shifters. The female notch on the shifters is similarly different. I believe this is intentional to make them incompatible. I would not be surprised to find a similar incompatibility with Sunrace vs. Shimano bar end shifters.

Both Sunrace and Shimano DT shifters and hardware mount on the same frame braze-on but the hardware and shifters are not interchangable.