Bicycle Mechanics - front derailleur bolt snapped

Installing a nos deore dx fd last night. I was using a diy shim bc the clamp was 31.8 and the seat tube was 28.6, so I wanted to make sure i got it on tight. after tightening all i could i realized it was too low, started loosening it and the bolt snapped.

2 questions
1)was the bolt just weak or are there other reasons this happens?
2)how do I get the little nut that is somewhat embedded in the derailleur arm out?

thanks!

.... so I wanted to make sure i got it on tight.

You probably overtightened it setting up the fracture. It's likely your shim was off size a bit causing you to feel you need more hold than it was designed for. Check dimensions carefully when you next install it (the shim has to be very close to 1/16") and if you feel you need more hold, use a tacking agent like the stuff 3m makes for light hold Post-it notes (comes in a stick), or carbon assembly paste.

The nut system is designed with exactly your problem in mind, just set a small punch against it through the clamp and tap it out the back. Odds you can remove what's left of the screw once it's out. You have a choice of buying an original screw, or using one made for water bottle bosses, or any stainless steel 5x.8 metric screw available at the hardware store.

thanks for the info. I used an old screw driver and a book as a hammer to push it out, I will try the tacking agent tonight.

thanks for the info. I used an old screw driver and a book as a hammer to push it out, I will try the tacking agent tonight.

What are you going to do when all books are Kindles?

What are you going to do when all books are Kindles?

Use one that's broken and out of warranty.

Use one that's broken and out of warranty.

yes, but they could replace War and Peace in terms of striking power.

the book i used, "managerial economics" sustained near fatal wounds. kindle might have come through less mangled.

i should just buy a hammer for the office

the book i used, "managerial economics" sustained near fatal wounds. kindle might have come through less mangled.

i should just buy a hammer for the office

Next time, go outside and find a rock.

Next time, go outside and find a rock.

Or use your head.