Wildwood

Need advice on a fork to headset concern, never experienced before.
Bike is an early '70s Holdsworth Pro with (supposedly) original fork, although the frame and fork serial numbers do not match.
The bottom headset race does not seat onto the fork steerer.
Picture worth 1,000 words. I gently filed the top of ridge to show it better in the pic.


The fork steerer has a 'ridge' where it joins the fork crown that prevents the headset from seating properly. The steerer (above the ridge) is 25.4mm and 26.4mm at the crown. Only a 1mm increase.

Have tried a '70s Campa headset and a new one but neither seat onto the fork crown.

What to do?

Andrew R Stewart 

The "ridge" is the fork crown race seat. It should have been both machined round to a 26.5mm diameter (allowing for a 0.1mm interference fit with the headset's race) and it's face/bottom flat/perpendicular by someone before the initial assembly. The .1mm interference fit will want a significant impact force to drive the race onto the seat. Best done with a tool which will evenly contact the race and slide on the fork's steerer, maybe extending above the top of the steerer which will let a hammer be used to create the impact. These tools resemble a length of pipe/tube with a fairly thick wall. Sometimes the amount of impact force is similar to driving a 10P nail into a chunk of hard wood.

What tool was used to try to install your race?

There are times when the race seat is not well machined or became ring notched by poor install/removal of a previous race (if the race cocks crooked a lot). Then a re-machining of the fork's seat is the good choice. Can this be done by a home "mechanic"? Sort of, but not with out care and skill with a hand file on the mechanic's side. These days few of us have had that kind of exposure to working to close dimensions with simple hand tools and if done poorly the race can end up sitting loosely and this is not good or right. I strongly suggest enlisting a shop (or well equipped home guy) to do this kind of work if at all possible.

As to the serial numbers not matching this is not uncommon for some factories back then. Frames and forks were often made in batches separate of each other and only combined when the F&F are painted. I have seen this with Holdsworthy and other English brands before. Andy

Wildwood

Thanks @Andrew R Stewart
Have only fit them on loosely with no tools or hammering involved.

Serial number difference not a concern, but another Holdsworthy has matching serial #s, a 1980 model - so post bike boom.

I have assembled a number of framesets and never encountered the 'problem' to the extent of this one. Caution to get a correct fit and proper seat is understood and I will heed your advice.

Andrew R Stewart 

With more modern headset race and bearing designs the race is actually only a seat for the bearing cartridge, not also a ball track surface (as is with most "classic" loose ball designs). So the bearing seating ring could be either split or meant to fit onto a conical crown seat (so no interference fit). Really cheap "American" bikes sometimes have a very loose fitting crown race. Andy

KerryIrons

Conversely, I have never installed a crown race on a fork that didn't need to be "hammered" into place. That is why they make crown race setting tools. If your previous experience had the crown races just slipping on without force, you were dealing with poorly sized crown race seats on those forks.

well biked 

+1 to crown races being an interference fit onto the crown race seat, requiring tools to install and uninstall. A crown race that installs loosely, without tools, is a mismatch to the crown race seat, not the other way around.

Andrew R Stewart 

Or with a design that didn't use a press/interference fit for the crown race.

With no knowledge of what previous bikes the OP was working on we can't be sure those other examples needed to be hammered down tight. I am quite sure the headset for this Holdsworthy will be an interference fit though. Andy

Andrew R Stewart 

Yet many 27.0 crown seats have been machined down to 26.4 (both are actually that .1mm larger, but that isn't a dimension listed in most all headset specs thus the race diameter spec being referenced) to allow for a replacement headset to work, for whatever reason why. Of course doing a non reversable procedure to a frame or fork is generally not one's first choice, sourcing the OEM spec headset is the better first choice. Andy

Crankycrank

This is one of the rare tasks that I'll take to a bike shop. They will have a special reamer tool to make the race round and the correct size and usually install your bearing race for you at the same time. Bring the headset with you that you will be using. Not really a difficult job to install the race but the shop ensures the steerer is machined properly.

well biked 

What I was trying to communicate to the OP was that, based on the two types of experiences reported with crown race installation, it's actually the crown races that required no tools and could be installed by hand that are the concern, not the crown race that fits too tightly to do that. As we've already covered, a properly fitting crown race should require a setting process, with tools, because of the interference fit. I probably didn't communicate that very well in my earlier post.

choddo

My father-in-law raced these and what I can contribute is; it’s Holdsworth, not Holdsworthy

grumpus

Looks like your filing has destroyed the concentricity of the race seat, which should be a firm interference fit. You could try taking it to a bike shop that has the necessary cutting and facing tool to clean it up, but I suspect that will just show the seat is now undersized. This may be useable with the addition of bearing retainer compound, but otherwise it will need a frame builder to add some bronze and machine it back to spec.

Wildwood

Thanks for all the input.

SurferRosa

Those are ISO/English values. A standard headset should work as long as the steerer is tall enough for the headset's stack height. I use a piece of 1" pvc pipe to install the crown race.

Aardwolf

I've got a couple of Holdsworths, both with original forks (matching numbers).
..
Fitted Tange Levin CDS JIS to both.
They were both hammered on at the local bike shop after I failed to install the Avanti race - don't have the correct diameter tubing (to use as a hammer).
If you get the right bike shop they won't charge

Wildwood

I used pvc once and it worked. But this one is tighter than I have experienced previously. I'm gonna let a shop handle it, got several to contact. This frameset I have high expectations for (ie, why I inquired here to get it properly right) - early '70s, perfect fit, original paint, orange&panels, chrome fork+socks, 531, bit 'o history. What more can I say?! (At least my minor/light filing did no harm.)


edit: I have always been under the impression that my English manufactured for Irish Harding distribution were produced under contract to the Holdsworthy company, that also produced Clive Stewart frames and others.
W. F. Holdsworth (nkilgariff.com)
i stand corrected if wrong
something like this - which may have been owned, possibly raced, by an Irish team, bitd. So, not Holdsworth branded, ever.




re-edit: Apologies, forgot this isn't C&V! thanks again for the headset advices.

Mr. 66

For shop service I use Wright Bros., Charles is excellent, but note he is a cash only business these days.

smd4

Which is why the shop tool is made of metal, and not plastic.

Andrew R Stewart 

As well as often having a closed top end suitable for impacting with a hammer. Andy

Kontact

Copper water pipe is ideal for this. Won't mar anything but transmits hammer blows like steel. $5 from the hardware store.