what would cause tuning machines to break ?

[killme]

I have an old kelly performer that I bought used about 16 years ago. It sat on a stand with no use for about 2 years and when I decided to clean it up I looked and 5 of 6 tuning machines were cracked halfway through just above the nut. I replaced them but have been curious as to why that happened. Thanks

[DonP]

Pictures?

[84sups]

It's happened to me on my mij PS4 5 of the 6 broke and one on my s470. Frustrates the hell out of me. Maybe they were over tightened but my ibanez doesn't have a ring on the headstock like it was over-tightened.

[xenophobe]

Overtightened. Possibly a bad batch of metal or deviation/error/fault in the manufacturing process. Could be a lot of different things.

[killme]

thanks guys i was not sure and didnt want it to happen again thats why I asked I got a few more guitars since I joined and dont want problems with them too

[tomanyjacksons]

I doubt pictures would break them.

Pictures?