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Old 09-19-11, 06:47 PM   #1
webster.kevin1
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Fork Eyelet Threads Damaged. Fixable?

So, I just picked up a 1987 Schwinn Voyageur a few days ago and after taking off the front Blackburn rack I found that I am unable to comfortably reinstall the mounting screw into one of the fork eyelets. Since the screw threads easily into the others I can only imagine that the fork eyelet is damaged. It screws in for a couple a turns before it stops. I'm afraid to turn anymore for fear of stripping it.

Is this something a LBS shop can take care of?

I did some searching on Bike Forums, but most of the stripped thread threads dealt with bigger (think bottom bracket) and thinner threads.
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Old 09-19-11, 06:50 PM   #2
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did you try threading it in from the back? It's a 5mm bolt, it's possible someone forced an 8-32 in there. They are very close, you should be able to get a 5mm tap and clean it up. I would think that most bike shops would be able to fix that.
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Old 09-19-11, 06:54 PM   #3
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did you try threading it in from the back? It's a 5mm bolt, it's possible someone forced an 8-32 in there. They are very close, you should be able to get a 5mm tap and clean it up. I would think that most bike shops would be able to fix that.
I did try to thread it from the back. No go.
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Old 09-19-11, 07:04 PM   #4
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Get the right tap and start by chasing out the threads to correct any minor damage.

For more serious damage drilling and tapping up a size on one solution, filling and re-tapping is another, as is sizing down and using a bolt with a locking backing nut which is something I often do with rack mounts to provide an extra level of security.

Last edited by Sixty Fiver; 09-21-11 at 12:42 AM.
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Old 09-19-11, 07:09 PM   #5
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The threads are M5x.8 and any bike shop will have a tap that size. It's possible the threads are just cloged with paint and a tap will clean them up completely.

At worst, if the threads are hopeless, drill the hole out to just clear the bolt and use a longer bolt and a nut. If you have clearance problems on the inside of the fork dropout, insert the bolt from the inside and use the nut on the outside. BTW, the nearest SAE size to M5x.8 is a #10-32, not a #8 bolt.
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Old 09-19-11, 07:11 PM   #6
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webster.kevin1: If you cannot clean up the threads satisfactorily, it is a simple matter to drill and tap the hole with a special oversize tap and to put in a threaded insert called a Helicoil to give you new, steel threads which will be stronger than the original.
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Old 09-19-11, 07:15 PM   #7
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Re-tap it, and thread a new bolt into it. Or, conversely, strip it out, and use a nut and bolt.
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Old 09-19-11, 07:25 PM   #8
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Sixty Fiver and pretty much covered it.
1. Chase original hole w/ 5mm tap.
if no go to step 2

2. Drill thru w/5.25mm drill or a 7/32" and use a long enough 5mm screw w/locking nut.
if you don't like the aesethics of nut and bolt combo, go to step 3

3. Drill thru w/5mm drill or #8 drill and tap for 6mm.

They are also thread inserts(heli-coil, Thread-ReNew, others) to return a buggered(technical term) hole to original thread sizes but it's not usually worthwhile for the average person to bother with.
I have even seen some things permanently epoxied in place because person never inteded to remove the offending screw/bolt, and then brought it to me because it suddenly became necessary.

Wow, 65er waas the last poster before I wrote this.

Last edited by catmandew52; 09-19-11 at 07:30 PM. Reason: spelling
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Old 09-19-11, 07:29 PM   #9
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Quote:
Originally Posted by dsbrantjr View Post
webster.kevin1: If you cannot clean up the threads satisfactorily, it is a simple matter to drill and tap the hole with a special oversize tap and to put in a threaded insert called a Helicoil to give you new, steel threads which will be stronger than the original.
Most forks and frames have too little metal around the dropout eyelets to allow any significant oversize drilling. That's why I didn't even recommend drilling and tapping to M6x1.0, never mind the oversize needed for a Helicoil. Either cleanup the current M5 threads or drill just enough to clear a 5 mm bolt and use a bolt and nut.
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Old 09-19-11, 07:45 PM   #10
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Originally Posted by dsbrantjr View Post
webster.kevin1: If you cannot clean up the threads satisfactorily, it is a simple matter to drill and tap the hole with a special oversize tap and to put in a threaded insert called a Helicoil to give you new, steel threads which will be stronger than the original.
I've used a Timesert to repair an eyelet. It is a little better in my opinion, in thin materials like an eyelet. One can also add some loc-tite to the insert, unlike helicoils.

Chasing the threads with the proper tap is the first course of action.

Edit: A Time-sert insert (or heli-coil) for M5 thread repair measures 5.9mm on the OD. Just a tad shy of the major diameter of an M6 screw.

Last edited by krome; 09-19-11 at 07:54 PM.
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Old 09-19-11, 07:57 PM   #11
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Thanks for all the help. I definitely freaked out thinking that if the threads were ruined, the possibilities of fitting the rack were ruined. I never even considered the possibility of drilling through the threads. I like the way you guys think. I am going to take it to the bike shop tomorrow. I'll let you know how it turns out.

Last edited by webster.kevin1; 09-19-11 at 07:58 PM. Reason: removed quote
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Old 09-19-11, 08:02 PM   #12
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A dab of JB Weld, drill and tap.

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Old 09-20-11, 04:44 PM   #13
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So, I took it to the LBS. He put a tap through to it to chase the threads. All better.
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Old 09-20-11, 05:15 PM   #14
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Quote:
Originally Posted by dsbrantjr View Post
webster.kevin1: If you cannot clean up the threads satisfactorily, it is a simple matter to drill and tap the hole with a special oversize tap and to put in a threaded insert called a Helicoil to give you new, steel threads which will be stronger than the original.
This is overkill for this application. When an M5 hole strips out, it's a simple task to tap it to M6. More than good enough for rack and fender mounts.
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Old 09-21-11, 12:44 AM   #15
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So, I took it to the LBS. He put a tap through to it to chase the threads. All better.
Nice when all you need is step 1.
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