The square wrenches that I have were angled too much to work well on the carriage lock bolt on my Atlas lathe. They also didn't fit tightly on the square head and are heavy so they tend to fall off.
This has a 5 degree angle to the square drive and fits a bit tighter on the bolt. It's lightweight so it stays put. I can lock the carriage tight without it interfering with anything.
Printed with 5 walls and 20% infill. Seems to be sufficient.
The author marked this model as their own original creation.