i was a pattern/model maker for 20 years. i made classified military items, parts for NASA, toys, and everything in between. i used 3 different drafting pencils. a .9mm for lettering and dimensions, a .5mm for general lines, and a .3mm for dotted lines indicating hidden lines. i also used different hardnesses of lead depending on what type of medium i was drawing on. i still have a large collection of the leads in my walnut Gerstner tool chest.
You mean sizes like this?
Quote from: mobilehomer on November 25, 2021, 01:28:28 PMYou mean sizes like this?way back in the days B.C. (before computers) the .9mm was for lettering and section cutting planes, the .7mm used for object lines, the .5mm for hidden and dimension lines and the 3mm was used with hard lead for creating very light construction lines that could easily be erased.
I'm sure all you other mechanical pencil fans recall using kneadable erasers, templates for both curves and erasing only tiny sections of a drawing, and using a sandpaper sharpener.
Wow!! Fantastic air gun related info.....
I took 2 years of architectural/mechanical drafting in trade school back in the very early '70s.We had some awesome mechanical pencils back then. Most didn't survive the modding to make them into #6 shot launchers. If you were at the front of the class you could stick a lead bb in the bulletin board but you also had a better chance of getting caught.