How do they get the eyes into sewing needles? And while we’re at it, how do they manufacture those perfect little metal balls that fit into the tips of ball point pens?
The holes are formed with a metal punch, before the needle metal is hardened. The manufacturing process for several types of needles is illustrated here.
I’m not sure how they make the tiny ball bearings for ballpoints.
Isn’t it obvious. Dwarves use a tiny drill punch to drill the center of the needle out to form the eye. He then picks up the discarded center and throws it to his buddy down the line. The next dwarf polishes it up and, if he can make it nice and round, then he has a nice tiny ball bearing that they can sell to the pen company for a tidy profit. I wouldn’t go into this line of work unless:
A) You are a dwarf
B) You have really go eyesight.
Sewing needle eyes have to be much cheaper to produce than making the apertures in syringes. Those are much smaller have to be made with much more precision.
I’m in an engineering design class, and our design project involves fabricating a needle. We had no idea how it was done, or even how to find how it was done. I was cruising the SD last week, and came upon this thread. I sent Squink’s link to a team member, and we ended up referencing the website.
Thank you Straight Dope, for helping my team fight ignorance!