TIL most people strip lens screw threads by using the wrong screwdriver

I was working on a beat up Canon FD 50mm last week and noticed the screws around the lens mount were all chewed up. The previous owner obviously tried to open it with a Phillips head when it takes a JIS (Japanese Industrial Standard) driver. They look almost the same but the JIS has a sharper point and sits deeper in the screw head. If you use a regular Phillips it cams out and strips the brass threads every time. I used to do this too until a repair guy in Chicago told me about it after I ruined a $40 lens. Now I keep a set of JIS drivers on my bench for any Japanese gear. How many of you guys still use Phillips on older Nikkor or Canon lenses?

3 comments

3 Comments

the_claire5d ago

The real trick is checking if the screwdriver tip has a tiny flat spot on the end. A proper JIS driver comes to a sharper point. I test mine on a junk lens first. Also, lots of people forget to use a manual impact driver for the really stubborn ones. A sharp tap straight down breaks the bond without any cam-out.

tessap735d ago

Repair guy in Chicago told me" - straight up, listen to that guy. Swapping to JIS drivers saved my poor old Nikkor glass. No regrets.

nancy_king295d ago

Heard a buddy strip a screw on his Canon 50mm from using Phillips instead of JIS.