Square Baluster Mount Kit

I wanted to replace a whole bunch of round wooden balusters with 1/2 metal ones. Which meant finding a way to install a square peg in a round hole. There's a commercially available solution but the cost per baluster was unpalatable to me for a few bits of plastic.

There's three parts to print here for each metal baluster:
Top: Round top of the baluster fits into this.
Bottom: Built to accept an 8mm bolthead.
Insert: Goes into the square bottom of the baluster and receives a 5mm bolt.

Everything has pretty tight tolerances by design.
The bottom and top parts are meant to be hammered into a 3/4 inch hole. They are slightly oversize so that they bite into the wood and do not spin. The inserts are likewise just shade too big and will need to be hammered in causing a bit of extra material to get shaved off.
I used some M5-0.8 x 30mm Bolts and nuts I found on Amazon and two nuts per bolt as in the picture.

Process:
Hammer the top and bottom pieces into your railings and the insert into th