Mangled Fork Crown
11-05-09, 07:03 PM
#1
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Mangled Fork Crown
I just got a frame and the fork crown has been filed something serious. When I put the fork Crown race on it is tight to go on but has a small bit of play once fully installed. What are my options?
Jake
Jake
11-05-09, 07:10 PM
#2
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Belzona...
I am a retired Millwright(Industrial Mechanic) and, from time to time, in industry we had to repair just such situations. Find some Belzona, mix it and goop it on.
This is not a permanent repair but I have seen such repairs last for years under demanding adverse conditions. When one considers the stress this bearing assembly will experience, my guess is that the repair will last for a very long time.
Belzona is a two part product that mixes up into a stiff paste. Follow the instructions and see how it works. You can always file it off again if need be. There is, of course the concern of getting the bearing race centered on the steering stem, but once again, still worth a try. The cost should not be to great.
Hope this is a help and I have done it? Yup! And with good results.
This is not a permanent repair but I have seen such repairs last for years under demanding adverse conditions. When one considers the stress this bearing assembly will experience, my guess is that the repair will last for a very long time.
Belzona is a two part product that mixes up into a stiff paste. Follow the instructions and see how it works. You can always file it off again if need be. There is, of course the concern of getting the bearing race centered on the steering stem, but once again, still worth a try. The cost should not be to great.
Hope this is a help and I have done it? Yup! And with good results.
11-05-09, 07:12 PM
#3
Stop reading my posts!
if the slop isn't too bad, consider some LocTite GREEN (for press-fitting, not threads).
11-05-09, 07:46 PM
#5
Senior Member
1. JB weld the race on
2. We had tool that was designed to 'raise' the metal. You'd roate it around a few times and the wheels would dig and leave a pattern behind. It worked OK.
2. We had tool that was designed to 'raise' the metal. You'd roate it around a few times and the wheels would dig and leave a pattern behind. It worked OK.
11-05-09, 08:08 PM
#6
Stop reading my posts!
JB might be the best trick and easy to find, also you can un-do it in future with heat and solvents.
I forgot about "Knurling" which is what miamijim suggests, the "poorman's " version of knurling can be done by striking a pattern of dots in the low spots with a sharp center punch. it does the same thing: raises the metal.
I forgot about "Knurling" which is what miamijim suggests, the "poorman's " version of knurling can be done by striking a pattern of dots in the low spots with a sharp center punch. it does the same thing: raises the metal.
11-05-09, 08:16 PM
#7
Senior Member
The process is called knurling. It displaces metal to create small ridges or mounds higher than the orignal surface of the metal. Inexpensive bicycles often have the bottom of the steerer tube knurled to hold the crown race in place without the need of a precision machined collar/flange. If done properly, it is an effective solution, though it will not stand up to repeated removal and installation of crown races like a machined collar/flange.
11-05-09, 09:17 PM
#8
Senior Member
Kind of scary that the undercut shows in the image, not a happy stress riser. Knurling would work, but I don't know if I would continue to use it. I am not an alarmist type, but I don't like how it looks from here.
