[70 Blackbird]

I am working with a 70 tach/clock assembly for my Formula. Unfortunately the clock reset stem is missing the threaded end, There is just a partial, single thread at the end.. Not sure if someone ground the stem off or what.. The clock came out of a single wire tach, so I believe this would have used the early black "flower" reset knob/keeper.

The questions I have:

Is the thread for the flower knob different than the thread on the later, silver knob/keeper? If so, what is the thread?

What is the overall length of the reset stem?

How long/deep is the threaded end that the knob keeper screws on to?

Thanks in advance.