Bowling Ball Thumb Insert - Jo Po

This is a thumb insert that fits into the standard JoPo Thumb holes.  It snaps into place much like the original.  This will not auto align for you like the OEM jopo insert, so you have to make sure you put it in the correct way each time.  Once locked in, it is secure and can be used. 

I made an outer sleeve that works with this here : Bowling Ball Thumb Insert Outer Sleeve  - Please note, I have NOT tested the outer sleeve in an actual bowling ball, so download and use at your own risk. 

Youtube video showing it being inserted - 

Please note, you probably want to sand the thumb holes, the printed model isn't really smooth… I start out sanding at 220 grit and go up through the grits to around 2000 and it's really smooth.  

I have a few different thumb sizes included, 20mm, 22mm and 24mm, 25, 26, 27, 28. 

This works with 3 of my bowling balls, but I can't guarantee it's going to work with yours, so your mileage may vary.  On the models I included, I have the very top layers a different color to show you the way it should be aligned.  When inserting into the ball, align the indicator portion of the thumb hole slightly pointed to the left of your finger holes, then insert and rotate to the right and it will click into place.  

Good luck!