More pictures on my Blog in case it helps. https://myrandomtechblog.com/misc/her...

My Herman Miller Aeron chair had a broken pin on the Tilt lock Sector Gear. Instead of buying a new part and having to wait (~$40). I just went ahead and drilled a hole where the pin was and tapped it and screwed in a screw to use as the missing post. Working good so far. My screw was one I had laying around. It was a 10-32 and maybe a half inch long. If I had my choice I would have found a screw that did not have threads close to the head, but went with what I had.


This appears to be a common problem in the early model Aeron Chairs as they now use a different setup with no pin to break. Anyways, this worked for me.


FWIW - I picked up this chair used for 100 bucks due to the tilt lock not working. So I wasn't to worried about breaking it more. I am not responsible if you try this and injure yourself or break your own chair more. I suggest having it professionally repaired :-)