Bolts

A series of bolts with hex heads.

Sizes are stamped on the heads.

6-32 6-40
8-32 8-36
10-24 10-32
1/4-20 1/4-28
5/16-18 5/16-24
3/8-16 3/8-24
7/16-14 7/16-20
1/2-13 1/2-20

I used PLA to print.
Layer Time 10 and Fan at 30%
Bed 60
Temp 210
First layer height: .24
First layer Line width: %120
First layer Speed: 25mm/s
First layerFlow: 1.05
First layer Part Fan Off

Brims.

For the smaller sizes, you may have trouble rendering the numbers on the heads in your slicer.