Building an Adjustable Cam Timing Gear Setup

Machining some 55Rc hardened steel gears, drilling, tapping and boring to fit a hub that will allow adjustments of camshaft timing without effecting the timing of other components such as the fuel injection pump. This particular setup is for a John Deere but the theory applies to most all diesels. Sadly the footage from the start of this project was lost but it was mainly just worn out inserts from turning the gears out and busted taps from cutting the threads in the 50-52Rc Gear for the locking bolts. If you need to cut threads in material like this I highly recommend trying the 5 flute OSG Exotap 10051 series. I power tapped with it to get the proper speeds, don't know how it would work hand tapping.