JoPo Interchangable Inserts – Installation Tips and Tricks

As I have noted several times – JoPo interchangables are the best on the market. As a pro shop operator and JoPo installer, I have learned a few things which are in the information below. This is a lengthly document so you may want to print it or go get your favorite beverage and take time for along read! As always, if you have any questions or comments, let me know. I will do what I can to help.


Installing a JoPo interchangeable thumb is just like most systems which use an outer (receiver) with an inner (insert). There are, like most systems some do’s and don’ts we recommend. I will explain it all below. Welcome to the last thumb insert system you will ever want to use!


The hole for the receiver is 1 ½” in diameter, the same as similar systems. The depth is the difference. For JoPo’s the hole needs to be 3.22” (approx. 3 jopo drill bit¼” – 1/32”) deep. This distance is from the bottom of the stop collar (if your drill bit has one) to the first edge from the clearance wings of the drill bit. Note: drill a pilot hole deeper than the hole for the receiver. 

Next is the receiver. The key is to rough up the outside face of the receiver. I use a wood rasp with a course face. Go around the entire outside of the receiver. There is a vertical groove on the surface of the receiver. Mark it with a yellow or white grease pencil – this is your alignment line at the back of the thumb hole!

Use a paper towel with rubbing or denatured alcohol inside the cut hole – make it as clean as possible. Place our JoPo Super Glue around the inside of the hole – you will have 45 seconds to place the receiver. Align the vertical line on the receiver with the surface mark on the ball for the backside of the thumb hole. The xtra deep pilot hole will allow excess glue to puddle down into it!

Trim the insert with the top of the ball and you are done! If you need to, place the insert and trim it too. Use our JoPo Twist Tool to place and remove the insert. Round edges as necessary.


If you have not worked with the JoPo Inner blank before here are some suggestions:

1) Test fit your insert solid into the JoPo – make sure it seats to the bottom of the blank

2) Use a rasp (I got mine at Home Depot) with a course grate for “roughing” up the insert solid

3) Use a 400-grit sandpaper to rough up the inside of the blank – I typically go in a rounded direction so the course sanding is perpendicular to the rasping of the insert solid. If the blank and the insert fit snugly from step one you may not need to do this – check twice – glue once!

4) Use a fairly long setting adhesive – this will give you time to place the solid in the blank. Fast curing glues used for finger grips is a real challenge. I would not recommend using those. If I can let the glue set overnight, I use a 2-part epoxy glue. If I need something faster, I use something like one of the fast-setting epoxy glues – Home Depot has a 5 min epoxy glue I use by JB Weld. It is pretty good.

5) Make sure when you place the glue inside the blank you spread it thin. The roughing up process will make for a tight fit.

6) Check the bottom of the Inner – see if there is any glue escaping at the bottom – wipe it off as soon as you see it – this can be a problem of fit if you don’t. I typically turn the insert upside down with the alignment pegs upward.

One final thought: I know from practice some of the glued blanks tend to swell during the year. I do two things: sand the outside of the blanks after the glue has set – test fit and sand as needed. And the second thing is to put a thin coating of Vaseline on the outside of the inner. I will do this on the threads sometimes or the bottom pegs. It all depends on what seems to be a problem – if it is hard to screw in – it is a thread thing, if it is hard to click into place – it is a peg thing. You will need to test it.


If you find solutions which have worked for your, please share them on this blog page. By no means do I think my approaches are the only ones. Please share your thoughts.



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