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French headset fit?

Old 05-15-24, 07:16 AM
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French headset fit?

99.44% done with my friend's Peugeot (separate topic), the headset brinnelled a bit. Velo Orange announced back-in-stock on their French headsets (sadly, not sealed-bearing) , and a quick eyeball-check of stack height of the bike suggested it would fit. So, one arrived last night. I got the old headset out, started on the new installation, crown race seemed tougher than usual to press in. Breaking out the micrometer, I measured the crown race at 26.34mm (but it's marked 26.4 on the bottom); the fork crown (chromed) at 26.52. D'ya think that's "interference fit" or a bridge too far? I'm ready to stick the fork in the chest freezer for a couple of hours, but...
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Old 05-15-24, 07:42 AM
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Their site:

https://velo-orange.com/pages/threaded-headset-basics

says they know a french crown seat is 26.5.

What does your old one measure?
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Old 05-15-24, 07:55 AM
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Originally Posted by oneclick
Their site: https://velo-orange.com/pages/threaded-headset-basics says they know a french crown seat is 26.5. What does your old one measure?
Interesting. I spent a few minutes wondering where I had mislaid a chrome fork (kinda hard to lose!) until I remembered I had stuck it in the chest freezer (didn't change readings, by the way. Meanwhile, I was reading this page, of course SHELDON BROWN, and I remeasured everything I can think of, I really think the bike qualified as French in the headset (I think the bike dates to 1981-1982 so there's always a risk threads could have changed over the years).

Yeah, old race is a whisker over 26.5; can I presume "ain't gonna fit"? And, of course, I am asking Velo Orange about this.
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Old 05-15-24, 03:37 PM
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Someone is going to hang me for this, but I have filed down a fork crown to make a crown race fit. Use a small file, going around and around the crown to avoid flat spots, and checking the fit regularly. It's pretty easy, which is why it's within my skill range.

But talk to VO first.
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Old 05-15-24, 08:39 PM
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Originally Posted by bikingshearer
Someone is going to hang me for this, but I have filed down a fork crown to make a crown race fit. Use a small file, going around and around the crown to avoid flat spots, and checking the fit regularly. It's pretty easy, which is why it's within my skill range.

But talk to VO first.
I've committed this and many other headset installation sins. I've gotten away with all of them.
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Old 05-15-24, 09:27 PM
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Originally Posted by bikingshearer
Someone is going to hang me for this, but I have filed down a fork crown to make a crown race fit. Use a small file, going around and around the crown to avoid flat spots, and checking the fit regularly. It's pretty easy, which is why it's within my skill range.

But talk to VO first.
It's difficult to file chrome, partly because it's harder than your files. But also because it's difficult to keep from knicking the chrome at the bottom of the crown race seat, where rust will show on the assembled bike. Maybe acceptable if you keep your bike grimy like I do — the grime both protects against rust and hides it when it happens. But if you keep your bike very clean then you won't have the protection nor the hiding.

To save your files from being dulled by the chrome, it is recommended to grind or sand off the chrome before filing. Wear a respirator when grinding chrome, it is toxic and carcinogenic. The plating is incredibly thin, so you don't have to take the diameter down much, just look for the color change. When you see steel instead of chrome, than you can commence filing. Coarse sanding cloth strip can do the "grinding". Again, it's difficult to avoid damaging the chrome (or paint) on the part of the crown that shows after the headset is assembled.

When filing, it's recommended to use a file with a safe edge, so you're not filing on the flat face at the bottom of the seat. Assuming that was precisely machined originally, you want to keep it that way. You can create a safe edge on a normal flat file by grinding the cutting teeth off the edge with a bench grinder or belt sander. An alternative to a safe edge is to place a thin 1" ID washer over the crown race seat before ginding/sanding and/or filing. Most people doen't have thin 1" washers though.

I put a shim of good steel over the steerer to prevent the file from knicking the steerer if you tip the file a little. I use a chunk cut from the middle of the toptube of a crashed lightweight (so it's thin enough*), then hacksaw it so it's a "C" rather than an "O". It can be slipped over the steerer, and being thin it will easily spring out enough to fit. The shim will help the file to stay flat (parallel to the steerer axis) as well as protecting the steerer.

* if the steerer is 1" (25.4 mm) and your target seat is 26.4, then the shim should be 0.5 mm, though it doesn't need to be exact. A nice light 531 frame will typically have 0.5 mm wall in the center unbutted section. Columbus SL at 0.6 mm is a little too thick, but probably close enough. SP or heavier 531 has 0.7 mm unbutt, and that's starting to get too thick. I'd rather go too thin than too thick, so a piece of 0.4 mm TT would be sweet. So hunt for a crashed lightweight to saw up. As a general rule it's useful to have various pieces cut from crashed frames, so I always have a few such chunks in my shop.

To file a cylinder without making facets, correct procedure is to drop your back hand, raise the forward hand as you push forward. So start with the back hand (that's holding the file handle) up high, so it has room to come down as you push. This results in the point where you're filing moving backwards toward you as you push the file away from you. Harder to explain than to demonstrate; see if there's a Youtube on it if you don't know what I mean. Don't exaggerate this motion, you only need to drop the back hand a little on each stroke to prevent faceting. Reposition often, taking a little off all around, measure, then take some more off. A sharpie mark can be helpful to show you when you have come all the way around back to your starting point. Slow iteration is safer and more precise than trying to take it all off in one go.

I learned all the above from an old Italian pro bike mechanic in the '70s when I was a teenager. I am grateful to have had him as a teacher and now I am paying it forward.
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Old 05-16-24, 12:08 AM
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Originally Posted by bulgie
It's difficult to file chrome . . . . <snip>
Fortunately, there was no chrome on the one I did. I got lucky.

Thank you for the wonderful explanation. I do not expect to ever need to do this again, so with luck I will not have to commit every detail to memory, but just being reminded of the toxicity of chrome dust makes it worth the price of admission.
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Old 05-16-24, 05:08 AM
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I'll presume that no one thinks I'll be able to install as-is? I was hoping to use a combination of (a) I never had a race installation tool before, so I've ordered one, it's sort of a slide-hammer arrangement, (b) chill the fork in the freezer, my chest freezer is at 10F, (c) heat the race in boiling water to expand it a tiny bit. Trying to think of a downside to trying it.

I wonder if I'd do better to try to open up the race instead of modifying the fork, so I'l still have the option of going back to the original headset. Let me guess: the race is made of pretty hard steel, too.

What I really was hoping for was an e-mail from VO: "Oops! Wrong race in the package, we'll send you the correct one right away". Well, usually I hear from them quickly, but not yet.

Originally Posted by bikingshearer
Someone is going to hang me for this, but I have filed down a fork crown to make a crown race fit. Use a small file, going around and around the crown to avoid flat spots, and checking the fit regularly. It's pretty easy, which is why it's within my skill range. But talk to VO first.
Originally Posted by noglider
I've committed this and many other headset installation sins. I've gotten away with all of them.
Originally Posted by bulgie
It's difficult to file chrome, partly because it's harder than your files. But also because it's difficult to keep from knicking the chrome at the bottom of the crown race seat, where rust will show on the assembled bike. Maybe acceptable if you keep your bike grimy like I do — the grime both protects against rust and hides it when it happens. But if you keep your bike very clean then you won't have the protection nor the hiding.
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Old 05-16-24, 05:23 AM
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I would make a careful measurement of the stack heights of the previous headset vs the Velo Orange one before proceeding with any metal removal.
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Old 05-16-24, 05:32 AM
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Originally Posted by tiger1964
I'll presume that no one thinks I'll be able to install as-is? I was hoping to use a combination of (a) I never had a race installation tool before, so I've ordered one, it's sort of a slide-hammer arrangement, (b) chill the fork in the freezer, my chest freezer is at 10F, (c) heat the race in boiling water to expand it a tiny bit. Trying to think of a downside to trying it.

I wonder if I'd do better to try to open up the race instead of modifying the fork, so I'l still have the option of going back to the original headset. Let me guess: the race is made of pretty hard steel, too.

What I really was hoping for was an e-mail from VO: "Oops! Wrong race in the package, we'll send you the correct one right away". Well, usually I hear from them quickly, but not yet.
I slammed on a crown race that was a little too small for the chromed seat. It went on with no problem. But the next time I serviced the headset, the crown race was cracked. I then removed the chrome and used a crown race cutter before installing the new race.

If you don't want to play with the fork, how about removing some material from the inside of the race?

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Old 05-16-24, 05:51 AM
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Originally Posted by gearbasher
If you don't want to play with the fork, how about removing some material from the inside of the race?
That really isn't possible. It's extremely hard steel.
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Old 05-16-24, 05:57 AM
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I really don’t know what the Velo Orange headset is intended to fit. It has a stack height of 41 mm. There are no new bikes being made with French threading, so cutting a fork to fit is a non issue. The vast majority of old headsets that it would presumably replace would be some thing like a Stronglight V4 with a stack height of about 38 mm or a Stronglight P3 with a stack height of about 34 mm…Lightrace is similar. The French crown race diameter can be either 26.5 mm or 27.0 mm. The Velo Orange headset comes with a 26.4 mm diameter crown race. You are left to machine the crown race to install properly or resort to butchery. If a fork was accurately cut to fill all of the threads for its original headset, you MIGHT be lucky enough to have enough threads to use the VO headset on a bike originally fitted with a V4, but definitely not for a P3 or Lightrace or similar.
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Old 05-16-24, 06:08 AM
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Originally Posted by noglider
That really isn't possible. It's extremely hard steel.
Did it; good sharp carbide tipped toolbit on an generic asian 7x10.

You do need a crown race with a good outer cylindrical section to grab.
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Old 05-16-24, 10:56 AM
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Originally Posted by bikingshearer
[snip] being reminded of the toxicity of chrome dust makes it worth the price of admission.
I shouldn't have stated that as a fact as if I were an expert — I'm not. I should have said "I have heard that..."
How toxic it is really, I dunno, maybe only for people who do it at work every day for years.
But for me, I'm gonna be on the safe side.

What I know for sure (again from being told, but by a scientist I trust who wrote a peer-reviewed paper on it) is welding fumes that contain hexavalent chromium ("Chrome-6"), which you get when you arc-weld stainless steel due to the high chromium content, is a strong carcinogen in the lungs. That's a far cry from room-temperature chromium dust.

Sorry if I exaggerated the danger.
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Old 05-16-24, 11:43 AM
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Originally Posted by oneclick
Did it; good sharp carbide tipped toolbit on an generic asian 7x10.

You do need a crown race with a good outer cylindrical section to grab.
Agreed, especially if the headset is not a top-tier item, which might not be all that hard. Also on modern sealed-bearing headsets, the thing you press-fit on the crown isn't even a race, it's more like a shim or adapter for the cartridge bearing, where the actual race lives. Those adapters aren't hardened.

Another method, accessible to people without a lathe (in case you don't know, oneclick 's "generic asian 7x10" refers to a metal-cutting lathe) is what I call a wind-up. A spiral of abrasive cloth wound tightly on a steel arbor, that you can custom-fit to the diameter you need by making it too big and then tearing off a little bit at a time until it just barely fits into the hole you're enlarging.

You need a variable-speed drill, a steel rod or tube (say about 3/8 or 1/2"), a vise and a hacksaw. And the abrasive cloth strip, often called "utility roll" or a few different names. Get quality cloth, it makes a huge difference. 3M brand is relaible, I get their Utility Cloth Roll 314D, usually in 60 or 80 grit, 1" to 2" wide. Often on ebay for a good price, even a partially-used roll of it can be found sometimes which is good if you'll rarely need it. Inch is cheaper than 2" of course, so get 1" if you don't need the extra width

Hold the rod or tube in the vise and hacksaw down from one end, as far as your cloth strip is wide. Your wind-up should look like this:


The tighter it fits in the hole the more accurate it'll be, so wind it as tight as you can before tearing off the tail to size it. Leather gloves can preserve your tender hands for winding it tightly.
In use it'll tighten more, and also the outermost winding will lose its abrasive, so you need a way to make it bigger again. The trick is tear off about two full winds, than make a new piece of cloth some amount longer than the piece you just tore off, and insert it under the last winding of the windup so the new srip is held in place and it builds the diameter back up.

This pic from my friend Alistair Spence shows his wind-up with a new "tail" of cloth installed:


You get two uses out of each extra tail you add, because when it gets the grit worn off, you can flip it so the other end is on the outside.

Preserve the work you put into winding it tightly — don't let it unwind. Hold it with your hand whenever it's not in the hole, and put a clamp of some sort on it to hold it tight when you set it down.
Another pic from Alistair showing it held with a spring-clamp:


This is a very useful tool, also for things like polishing out gouges or rust-removal in the seat tube where the seatpost goes in, or the steerer for a quill stem. So I advise making your arbor (the rod with the hacksaw cut) as long as you might want to reach into a seat tube or steerer someday.

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Old 05-16-24, 12:42 PM
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Odd that VO's website says that the crown race is 26.5 for French headsets and the crown race for the French headset they sell is 26.4.

https://velo-orange.com/pages/thread...20or%2025.4tpi.

https://velo-orange.com/collections/...thread-headset
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Old 05-17-24, 07:58 AM
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Originally Posted by gearbasher
I slammed on a crown race that was a little too small for the chromed seat. It went on with no problem. But the next time I serviced the headset, the crown race was cracked. I then removed the chrome and used a crown race cutter before installing the new race.
Thanks for the warning! If I do the heat-n-chill, maybe not too much "slamming" needed? The headset is not that expensive and I really want the option of "go back to stock" if something bad happens.

Originally Posted by El Chaba
I really don’t know what the Velo Orange headset is intended to fit. It has a stack height of 41 mm.
I brought that up to Igor at VO a couple of years ago, in hopes that the headset could be re-engineered. Well, the new ones are in stock, of which I got one, not changed. Insurmountable problem? My 1961 Gitane is still on a brinelled headset. I found P3's on eBay, NOS, really expensive and in each case the bearings missing (so loose balls time).

Originally Posted by oneclick
Did it; good sharp carbide tipped toolbit on a generic asian 7x10. You do need a crown race with a good outer cylindrical section to grab.
Thanks for reminding me that I have nether machine tools not the needed skills! And, no, the base-of-the-race is all of 2mm. I was at first thinking stick the race in a vice, and go round-n-round with a Dremel... how could that be worse in terms of out-of-round or unconcentricity (is that a word?) than hacking away at the fork?

Originally Posted by bulgie
Another method, /// is what I call a wind-up. A spiral of abrasive cloth wound tightly on a steel arbor, that you can custom-fit to the diameter you need by making it too big and then tearing off a little bit at a time until it just barely fits into the hole you're enlarging. You need a variable-speed drill, a steel rod or tube (say about 3/8 or 1/2"),
Local HD has 1/2" ALUMINUM tubing, allegedly, I wonder if that would work (I have a 1/2" drill handy, a heavy beast so not handy for delicate work)

Originally Posted by bikemig
Odd that VO's website says that the crown race is 26.5 for French headsets and the crown race for the French headset they sell is 26.4.
Coming up on exactly 2 days since I e-mailed VO, no answer on all this, including those two links. I think I am on my own. Installation tool arrives tomorrow, I'm going to need to make up my mind eventually.
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Old 05-17-24, 12:42 PM
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Originally Posted by tiger1964
Local HD has 1/2" ALUMINUM tubing, allegedly, I wonder if that would work (I have a 1/2" drill handy, a heavy beast so not handy for delicate work)
Alu makes a poor wind-up arbor; look for some steel. The problem is strength. When the wind is tight, it can crush the arbor, closing up the slot, and then you can't get another piece of cloth to go in. Also alu will get gouged up by the drill chuck.

A longish 3/8" bolt with the head and thread cut off would do nicely if no plain steel rod is available. 1/2" is even better if your drill chuck opens that wide, only downside is is increases the minimum size you can adust it to. Only an issue if you're trying to clean up a small hole. I have several arbors in different sizes, and I choose the largest one that'll fit in the hole with a few winds of cloth around it. I even made one about 2" diameter where it grips the cloth, though of course it had a smaller shank to fit the drill. That was for cleaning/truing the bores of eccentric bottom brackets on tandems.

The reason to make the arbor as large as possible is mostly to prevent the little bit of cloth that goes in the slit from tearing. If that bit tears off then you have to unwind the whole thing, re-insert the cloth in the slit and wind up again. Only a slight annoyance unless you're in a hurry. Another reason to buy good-quality abrasive cloth. The main reason though is the grit lasts longer on quality stuff. The "quick-release" grit on the cheap stuff is going up your nose unless you wear a good mask — you're working in a cloud of abrasive grit particles. That was a pretty major quality-of-life issue for me when I was doing it all day as a framebuilder. But even now in retirement, for occasional use as a hobbyist, I have no patience for the cheap cloth they sell at the hardware store. Constantly having to replace the business end of the strip because you get hardly any use out of it.
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Old 05-20-24, 08:40 AM
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Originally Posted by bulgie
Alu makes a poor wind-up arbor; look for some steel. The problem is strength.
Well, glad I did not go buy it then. Future project!

So I carefully put the race in a vise, and lightly went round-and-round with a Dremel, and knocked off a couple thousandths in the hopes that the results would be concentric. Well, in conjunction with chilling the fork in the chest freezer, the race went on without excess pressure. The headset is assembled and feels fine, a test ride is coming. Even the stack height worked out, I was able to retain the washer and I had the correct amount of steerer showing to re-use the original Stronglight top nut (which was in good shape) to help keep the “vintage look”.
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Old 05-20-24, 11:48 AM
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Originally Posted by tiger1964
Breaking out the micrometer, I measured the crown race at 26.34mm (but it's marked 26.4 on the bottom); the fork crown (chromed) at 26.52. D'ya think that's "interference fit" or a bridge too far? I'm ready to stick the fork in the chest freezer for a couple of hours, but...
Unless you do this for a living, you are not going to measure the internal diameter correctly using a micrometer. You'd be lucky to measure the external diameter correctly as well.
I would trust the 26.4 marking on the crown race. Ask VO why the crown race is 26.4 and not 26.5.
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Old 05-20-24, 12:26 PM
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Originally Posted by icemilkcoffee
Unless you do this for a living, you are not going to measure the internal diameter correctly using a micrometer. You'd be lucky to measure the external diameter correctly as well.
Hey, thanks for the vote of confidence!

Originally Posted by icemilkcoffee
I would trust the 26.4 marking on the crown race. Ask VO why the crown race is 26.4 and not 26.5.
I kept getting readings of 26.36 or 26.37 on the crown race. The fork crown varied too (or at least my measurements did); let's call it 26.55; I'm concluding they want an interference fit. So, I ground a little, and measured -- rinse and repeat.

So, I've brought it up to VO a couple of times now. The response: "you did it the correct way". Using an actual machinist to "do it right" would be been a superior alternative. But the last time (non-bike) I looked around for one for a small job, apparently they are all contractors for NASA here... or price their work as if they did. More likely, just not interested.

Well, maybe this time I just got lucky.
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Larry:1958 Drysdale, 1961 Gitane Gran Sport, 1974 Zeus track, 1988 Masi Gran Corsa, 1974 Falcon, 1980 Palo Alto, 1973 Raleigh Gran Sport, 1974 Legnano. Susan: 1976 Windsor Profesional.



Last edited by tiger1964; 05-20-24 at 12:55 PM. Reason: .
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