Reverse Kingpin Kit
Here is a kit to take any regular kingpin fingerboard truck and make them into reverse kingpin.
They will lower the kingpin height so that you have a smooth grind across the trucks.
Kit comes complete with 3 reverse kingpins, (1 is to be used as a tread maker.) A set of O-Ring Bushings (Your Choice of color) and a Allen Wrench.
I have found it cuts the threads easier if you start from the bottom of the baseplate, dont bottom out the kingpin, just start some threads. then assemble the trucks.
Start with the kingpin, add a washer (If desired) add the small O-Ring, then the Truck Hanger, and finally the Large O-Ring. Then mount the assembly to the truck base plate and adjust the kingpin in for you desired quality.