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dfcas
Joined: 11 Jan 2004
Posts: 2815
Location: hillbilly heaven9/30/13 3:05 PM |
Would you drill a fork?
I building up a touring bike with cantis and want to use a fork mounted cable stop. The hole in the fork is too small for a receesed brake nut on the back side. The bolt goes in OK, but the nut is too large for the hole. I rigged up a smaller, longer, thinner bolt that goes all the way through, but its pretty flexy.
The fork is a heavy steel unicrown, and I'm thinking about enlarging the hole on the back side. Thoughts?
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Dave B
Joined: 10 Jan 2004
Posts: 4511
Location: Pittsburgh, PA9/30/13 3:22 PM |
I've done it several times and there is no problem. The OD of typical recessed brake nuts in 8 mm and a 5/16" drill bit works to enlarge the hole properly.
For caliper brake mounting I always warn the owner to drill the BACK of the fork crown only.
No worries and it's a common way to adapt older nutted caliper brake forks to newer recessed brakes.
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Sparky
Joined: 08 Dec 2003
Posts: 19084
Location: PDX9/30/13 3:38 PM |
Steel for sure. Even alum crown carbon...
From my stupid phone...
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dfcas
Joined: 11 Jan 2004
Posts: 2815
Location: hillbilly heaven10/1/13 11:40 AM |
Thanks for the tip Dave B. I drilled it in steps up to 5/16 and it worked fine, much more solid now.
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Dave B
Joined: 10 Jan 2004
Posts: 4511
Location: Pittsburgh, PA10/1/13 5:06 PM |
Glad it worked out. It's really a pretty straight forward modification and an easy way to "modernize" an older fork.
The real trick is drilling out a rear brake bridge to accept recessed nut brakes since you don't have room to fit a drill motor and bit between the front of the bridge and the seat tube and you do NOT want to drill out both sided of the bridge. I've done this by clamping a short 5/16" bit sideways in a Vise-Grip and turning it a fraction of a turn at a time. It's a bit slow but it does work.
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JohnC
Joined: 10 Jan 2004
Posts: 1939
Location: Glastonbury, Ct10/2/13 9:06 AM |
If you have to do that brake-bridge thing more than once, an inexpensive right-angle adapter for the drill is probably a good investment.
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Dave B
Joined: 10 Jan 2004
Posts: 4511
Location: Pittsburgh, PA10/2/13 10:22 AM |
quote:
If you have to do that brake-bridge thing more than once, an inexpensive right-angle adapter for the drill is probably a good investment.
Yes, but the adapter has to be small and you must use a very short bit. The space behind the seat tube is very limited and the gaps on the bikes I measured vary from 3-1/4 to 4".
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