Printing Fine Detail Including Screw Threads

I have been printing very small pieces with the Phenom. I spend a lot of time tweaking the settings, and orientation to get the pieces to print correctly. My latest project is printing this small knob. Overall it is 15mm tall. The short end is a 5mm long M3 thread. The long end has 5mm splined end to hold with your fingers. I cannot get the splined end to show up no matter what settings I am using. The resin is new in the bottle Peopoly Deft Gray. I’ve started with the default setting of 12s exposure time, and 50s bottom time. I tried 11s and 13s each, again with different part orientations. So far, I have not been able to get a successful print. Is there a trick for more detail for smaller parts?

I would try making the spline deeper . IF it prints that was the problem