That is the coolest answer I have seen in a long, long time. I enjoyed the explanation with pictures.
I wish we could have more of the same in this section.
Here is the difference inside your shaft. Reposted with permission from Bob Dzuricky:
Gary
what does the backward compatibe mean and how would you modify an old shaft???
The picture shown above was originally used on my website to help explain why I made the switch from the std 3/8-10 pin to the Flat Bottom pin. The reference to backwards compatibility was aimed at cues that I made in the past.
When I used the std 3/8-10 pin, I bored my shafts to .302" diameter before tapping. The FB style pin has a .308" minor diameter & will not fit unless the .302" diameter is enlarged to .308". It takes about 2 minutes.
Most other 3/8-10 shafts will not require modification. They are usually bored/drilled to .3125" diameter & will have plenty of clearance for the FB pin.
There are plenty of good threads like this, many, many as a matter of fact but they get lost in the shuffle, I suggested a sub section to the ATCM, but never got an answer so we are left with the search option. It works well.
The picture shown above was originally used on my website to help explain why I made the switch from the std 3/8-10 pin to the Flat Bottom pin. The reference to backwards compatibility was aimed at cues that I made in the past.
When I used the std 3/8-10 pin, I bored my shafts to .302" diameter before tapping. The FB style pin has a .308" minor diameter & will not fit unless the .302" diameter is enlarged to .308". It takes about 2 minutes.
Most other 3/8-10 shafts will not require modification. They are usually bored/drilled to .3125" diameter & will have plenty of clearance for the FB pin.