Fork Crown Race Seat 'repair'

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Fork Crown Race Seat 'repair'

Postby nigel1963 » Thu May 02, 2013 9:08 pm

Time to get my stuff in one heap and get this bike built.
The seller kindly negelected to advise that the fork crown race seat has been abused as shown on the following photographs - Center punch marks in a zig-zag pattern around the whole diameter and some galling where I suspect a race was twisted off. :shock: I have a used steel Campag head set; the fit interference over the punch marks is at the upper end of the range.
I've decided to get the crown race seat re-machined. I am familiar with a few good machine shops in Brisbane, but if someone has used a tame machinist/fitter to fix a like issue anywhere east coast it would be great to hear from them.
Given the cut will be light, were there any issues? [EDIT]

http://www.flickr.com/photos/93274691@N ... hotostream
http://www.flickr.com/photos/93274691@N ... hotostream
http://www.flickr.com/photos/93274691@N ... hotostream

Thanks, Cheers
Last edited by nigel1963 on Fri May 03, 2013 1:43 pm, edited 2 times in total.
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by BNA » Thu May 02, 2013 9:50 pm

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Re: Fork Crown Race Seat 'repair'

Postby twizzle » Thu May 02, 2013 9:50 pm

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Re: Fork Crown Race Seat 'repair'

Postby RonK » Thu May 02, 2013 9:55 pm

I'd just be getting some emery tape and giving it a good going over with that.
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Re: Fork Crown Race Seat 'repair'

Postby singlespeedscott » Thu May 02, 2013 10:18 pm

What's wrong with the steerer? Looks ok to me.

Often steerers are centre punched because the bottom headset race is a loose fit. I dare say the original owner fitted Italian threaded headset and found that the bottom race was a loose.

Italian threaded headsets use a 26.5mm bottom race whilst ISO (English) threaded headsets use a 26.4mm bottom race. By centre punching the steerer there is enough interference to hold the Italian race in place.

I wouldn't machine it because you will only further undersized the steerer and then nothing will fit without a shim. Which IMO is naff and dodgy. I would just fit an English threaded headset and be done with it.
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Re: Fork Crown Race Seat 'repair'

Postby WyvernRH » Fri May 03, 2013 9:41 am

Got to agree with RonK and SSS, looks OK to me. This was a common 'fix' to cope with headset size differences. Me personally, I prefer using a coke can shim to pad out the steerer so the race is a tight fit rather than marking the metal. You can glue the shim on if it worries you not being attached.
I would just use a fine file (or emery paper) to ease off the 'flash' from the impact marks and then go and find a soft drink can of your choice (or find a different headset that fits)
Cheers
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Re: Fork Crown Race Seat 'repair'

Postby Mark Kelly » Fri May 03, 2013 11:07 am

Third option: use a Chris King headset. They are still available in 1" threaded: the standard baseplate is 26.5mm but you can get undersized ones to fit worn or remachined crown races.

Yes they are expensive but they're worth every penny. The new graphics let them blend in on a classic frame.
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Re: Fork Crown Race Seat 'repair'

Postby singlespeedscott » Fri May 03, 2013 7:09 pm

Campagnolo Record is half the cost of a Chris King. Plus they are ISO meaning a 26.4mm bottom race which means a tighter fit.
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Re: Fork Crown Race Seat 'repair'

Postby Mark Kelly » Fri May 03, 2013 9:32 pm

singlespeedscott wrote:Campagnolo Record is half the cost of a Chris King. Plus they are ISO meaning a 26.4mm bottom race which means a tighter fit.


True that.

As a side note, I just took apart an old bike of mine that I'd rebuilt for one of my sons a few years ago. Because I didn't have the correct Campag. tools I haven't serviced the headset since new in 1991 (the bike was all C Record except the seatpost). When I finally removed it I found the grease was a bit stiffened but otherwise it's in perfect nick. I might replace the balls before I re-install it on the frame I'm building to suit the group, it'll probably go another 22 years.
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Re: Fork Crown Race Seat 'repair'

Postby singlespeedscott » Fri May 03, 2013 10:30 pm

I've pulled apart 40 year old Campagnolo headsets and they have been perfect other than hardened grease. Campagnolo always used high grade ball bearings.
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