Help finding hardware for a DIY shift knob

[craigslist]

I want to make one of these myself: Bambino baseball shifter | Store | RockNob gear shift knobs

I figure a baseball $12 and $5-10 worth of parts is reasonable so i don't want to pay nearly $50 for something I feel like I can make on my own.

I just don't know what type of hardware I'll need to connect the baseball. Any suggestions? My plan is to just drill out a baseball and fit the hole with an appropriately sized threaded insert of some sort, I just don't know what type of insert. Any help would be greatly appreciated! Thanks!

 

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I'm not sure how you want to do this because there is a lot of soft material in there...

 

[craigslist]

I was leaning towards using JB weld to hold some sort of threaded insert in place. I'm just not sure what type of threaded insert or where to find one.

 

[tincan86]

i just started with a pilot bit then worked my way up to a drill bit that was just smaller than the shaft of the shifter. I then took the ball and threaded it on the shaft