Summary

This is a printed connector shell for a near-Prologix-compatible GPIB to USB adapter project. It fits a 24-pin male GPIB connector and an Arduino Nano USB.
The Arduino GPIB code was written by Emanuele Girlando. All credit for this project goes to him.

Instructions

To complete this project you will need:
Arduino Nano USB board (clones work fine) & Arduino IDE
Male GPIB connector (such as Cinch 57-10240)
Wire-wrap wire & tools
Four 4-40 x 3/4" screws & nuts for the shell halves
Two 2-56 x 3/8" screws & nuts to hold the GPIB connector into the shell
Arduino GPIB Software v6.1 (as of 8/2015) by Emanuele Girlando.

Complete use, wiring and testing details are on his Website, egirland.blogspot.com and click on the "GPIB" tag.
Or http://egirland.blogspot.com/2014/03/arduino-uno-as-usb-to-gpib-controller.html as of 8/31/2015.
Or search on GPIB USB Girlando if the link is bad.

Assembly:
The 4-40 holes might need a bit of reaming with a #34 drill bit depending on your printer's ooze factor.
I used 30% fill, raft and support with ABS. Top and bottom halves print simultaneously.
The 4-40x3/4" screws are a bit long. I filed them down a bit. 11/16" (!) would be ideal.
M3x16 would work fine with a bit more reaming.
The 2-56 nuts may be a tight fit into their slots depending, again, on your printer's ooze factor.
The adapter doesn't need the GPIB jack screws as it will plug right onto your instrument and weighs almost nothing.

Arduino GPIB-USB Connector Shell