Sunday, February 3, 2013

Fixing a fender mount

The bracket that attaches my home made (half) front fender to the fork crown had finally become victim to aluminum's terrible fatigue strength (in other words, it broke).  So I decided to do it the right way and use steel this time.
"mud brake"


What was left of the original bracket
The material came from a drawer slide which was conveniently the perfect width and also had a conveniently placed hole.  It's like it was meant for this purpose.  This steel is also twice as thick as the old bracket.

Cutting the drawer slide
This fancy new pivoting vise made the job easier
After hack sawing off my peice, I was able to use aviation snips to cut off the unneeded angle parts to obtain a flat piece.
Some layout work
1/8" holes for pop rivets, 1/4" to mount to bike
I drilled holes for the corners because I was taught a radius corner is 10 times stronger than a sharp one.  The original bracket had sharp corners which probably contributed to its ultimate doom.  That, and I had to bend it a back and forth a couple times to get it in the right position, a big no-no with aluminum sheet metal.  Also, mud.
The new bracket completed
Some snipping, a lot of filing and some bending later, the piece is complete.  The new one has less distance between the 1/4" hole and the fender so it effectively increases the wheel clearance... I still don't think all that mud would fit through though.

Back in action, now all I got to do is make the rest of the fender!
One of the rear fender mounts is already cracked, but luckily it has a mount on either side of the seatstay bridge so the other one is keeping it from moving.

This is how the end of the fender attaches to the fork ends.

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