bulgie 

French is larger, at 16 mm nominal, usually about 15.96 - 15.98 actual
English at 5/8" is 15.88 mm nominal, usually about 15.6 - 15.8 actual

I just measured a dozen cottered spindles, and I think I found that I have only two French 16 mm diameter, the rest being English 5/8". Some of my Stronglight spindles, despite being made in France, measured in the English 5/8" range. Those 5/8" Stronglights are stamped with an A next to the overall length, and my one 16 mm Stronglight doesn't have the A stamping, so I think the A might mean Anglais. I took pictures of all those spindles with their sizes written in sharpie, stuck them here if anyone is interested.

The squirm from your French crank on an undersized English spindle can definitely cause problems with the cotter.

Care to clear up the apparent discrepancy between "has never filed" and "when he does file"?

Hmm, somehow I never once saw a mechanic use a grinding wheel on a cotter. Any wheel tends to make a hollow-ground shape, not a flat plane. I consider using a file a no-brainer since it's plenty fast and makes the desired shape "naturally".

Ha! If you define "ace" as someone who "could make cotters fit smooth", then we had more than a handful just at the shop I worked at in the early '70s. Because all of us could make cotters fit smooth (and work flawlessly even for strong riders). It was a large shop with a half-dozen mechanics, sometimes more. In order to not have to lay people off in the winter, they offered cut-rate complete overhauls, and we all did tons of them. Cottered bikes were still very much a thing then, so even new or 1-year-old bikes coming in for o'hauls had cotters, not all of course but probably a majority. (Not much Ashatabula/OPC IIRC, probably because those people didn't believe in paying a mechanic to service their cheap-ass bikes.)

You'd probably disagree that your definition of "ace" includes me and mechanics my age, but I would say the secrets are still very much with us. I was a teenager working after school and weekends at first, not one of the senior full-timers there until later, but I and other 'kids' there learned cotters well and quickly. By the time I was out of high school in '75, I felt I was an ace. I worked there full-time for a year as "assistant service manager" before going off to college, and did more cotters in that year than most currently active bike mechanics do in their entire career. I taught the tricks to new hires and supervised their work, but honestly just about any teenager can learn this quickly and not need any more coaching. It's just not that difficult.

Mark B

63rickert

OK, French is 16mm. The 15.5mm number comes from the Bikesmith/Stonich webpage. Silly me, I believed that. The guy is a toolmaker, he would own good measuring tools, would know how to use them. And he is working with just these parts. Helpfully, his copy includes a conversion, 15.5>0.610”. It is so rare to see an accurate metric to English conversion I fell for the whole thing.

Lesson#1. Believe nothing anyone says about bikes. Nothing, ever.

Lesson#2. Never ask a question. Figure out everything from scratch all by yourself.

It would be possible to go through all your other points but why. Will just repeat something said above. I asked a bike shop owner of 53 years, who I have known for 52 years, if he could do this. He said he had no one he would trust with a cotter. So I asked for a referral. He said there was no one. All dead. Around these forums everyone drank this knowledge with their mother’s milk. Same people who can’t fathom how to operate toe clips.

3alarmer 

...if you look at the sides of the grinding wheel, I'm certain you will see a flat plane. This is what you use to grind them to full cut before a light filing for finish. Without a bench grinder, I don't think I would ever work on another Peugeot with cotters.

bulgie 

I think the 15.5 mm thing must be real, since it's also on Sheldon Brown's pages. I just didn't have any of those to measure, among the 12 spindles in my pile.

But I asked on CR and got some pretty authoritative confirmation that Stronglight at least (maybe not all French) was 16 mm. I mean they made both sizes, 5/8" and 16 mm. And the "A" stamping on the spindle does mean English (5/8"). Magistroni also was 16 mm, but maybe not all Italian cranks.

I checked in Sutherland's 3rd edition (1980), it says French and Italian are 16 mm, no mention of 15.5 mm. Still that's just one source. I think we need more data to say anything definitive, but I can't believe that Mark Stonich or Sheldon Brown would get this wrong. There must be a 15.5 mm standard also.

- Mark B

BFisher

You know, you could have measured the damn spindle yourself. That's what most here who have offered you excellent guidance would have done, you know, folks with many decades of actual wrenching experience and not just some guy with plenty of vicarious experience through his mechanics.
Bulgie is right. It's not that hard if you have at least a bit of mechanical aptitude. You admitted that you don't. Please save the "never ask a question... " drama. It is frankly childish.
Hope you enjoy your newly installed cranks.

bulgie 

Ha ha, but is that OSHA approved? <jk>
I question whether it's really much faster than me with my 14" bastard file, considering that after grinding, you still need to walk over to the vise and clamp the pin for the finish filing.

Yeah those Peugeots took a really deep "facet" didn't they? We used to buy cotters from Peugeot with that shape in them already, but those'll be long gone now. Other than the hassle of more grinding/filing to get there, I liked the Peugeot shape because the deeper cut made a wider interface, less likely for the spindle to make those notches that you get when the pin isn't in tight enough. All pretty theoretical though since with good quality cotters, just about any angle or depth of cut can be durable enough if installed correctly.

-Mark B

bulgie 

This thread wouldn't be complete without the Helms cartoon:

Note cartoon guy isn't employing Best Practice, bracing the crank to the floor as shown here:

Of course that drawing is wrong too -- wrong hammer (use a nailing hammer over a ball-peen) and most importantly, wrong hammer angle. Why did the idiot draw the hammer at that wacky angle? Or in this case I should say whacky. Plus I use a drift punch with a concave end that holds itself centered on the pin, but most people don't have one of those. And they show the bracing block being made of wood — not the best material though it's mos def better than nothing.

When I was in Beijing in the early '80s I rented a Chinese singlespeed (for something like 5 cents a day) and immediately brought it back because of the clunk-clunk every pedal stroke from a loose cotter. The guy just hammered on it like crazy with a BFH, which didn't do much, all the impact being absorbed by the too-soft tires. And as we all know, once those notches have been made in the cotter from riding loose, you can't fix that just by tightening. Oh well I just rode it around with the slightly-diminished clunk-clunk, and had a great time getting lost anyway. I rode through Tienanmen Square at rush hour, back when there were almost no cars and hardly any motorcycles. Just a million black bicycles, every single one with cottered cranks and roller-lever "stirrup" brakes. Fun! Will we ever see that many bikes in one place ever again? Their streets are all clogged with cars now, so sad.

But I digress.

I have a British-made crankset from the mid-60s called Wedge-Lock*, that used unique cotters that they claimed needed no press and no hammering, just tighten the nut. And just loosen the nut and wiggle the cranks a bit to loosen the cotter, no hammering on that end either. They called it "Blitz" mounting. (I like that just 20 years after the war they could already use the word blitz jokingly.)

I've been afraid to try them, not because of the cotters but because they're hollow (tubular), with pedal and BB ends brass-brazed (sometimes called bronze-welded) to a tubular center section. They may not have tested them with someone as big as me, and at my age I'm not as unbreakable as I once was — I really hate falling off. I've broken two cranks and one pedal axle. Thrice bitten, four times shy.

The wedge-lock cotters appear to really work though, maybe from being high-strength. Heat-treated? I'm taking this from the condition of mine — old enough that the toestrap has worn through the chrome plating, and the cotters are unmarked by the spindle. I seriously doubt they've been replaced — because of their unique shape, spares must be rare as rocking-horse manure.

*The name Wedge-lock was also used for a cotterless crank. Confusing? Probably they weren't both on the market at the same time. I've never seen one of the cotterless ones; I'm guessing they didn't catch on.

​​​​​​​

- Mark B

3alarmer 

...if it needs to be done quickly, you need to take it to someone else.

Reynolds 

​​​​​​​Another interesting design is T A Criterium crankset.

Johno59

You can file Chicom to absolute perfection but they will soon start creaking. Like most things made in China the metal is complete junk.
Reuse original pins. Even if the threaded end is damaged a M6 die goes straight down the original thread, enabling a new nut and washer to secure the pin.
New good quality cotter pins are available but expect to pay at least 5 x the money as the Chicom junk.

Mad Honk 

So in reading all of this thread, I am struck by the fact that no one has not explained how to use a C-clamp and a socket to use as a cotter press. We used that set up until I could buy the Var tool. However the filing as described is fairly well described and does indeed make sense from a mechanic's point of view. Cottered cranks are not really difficult to repair / replace. I find that getting the right size cotters is the more difficult part of the repairs, rather than getting the cotter cut correct. just an observation, Smiles, MH

Reynolds 

I can't believe so much hype about something as simple as filing a flat surface to match another. If only a few ace mechanics could do it in their day, and none today, what about wheelbuilding? I have seen teens learning to hand file a perfect cube in a few months of shop class.

rhm

I don't like the C-clamp method. It's easy and reliable, if done right, but also easy to screw up, especially if you omit a key step that is, sadly, usually missing from the instructions.

Reynolds 

Not any C-clamp will work, needs to be a very strong one.

branko_76 

If you own or work on bikes with cottered cranks, then you owe it to yourself, or the person who owns the bike to use the proper tools for removing and installing crank cotters.

Hammers, wood blocks, c-clamps, etc are not proper tools for the job. If a so-called mechanic ever took a hammer to my bike, I'd feel compelled to do the same to his cranium....

Mad Honk 

Branko,
As a professional mechanic I use a Var Cotter press. However it can be done with a less expensive C-clamp than the Var version of a C-clamp. I am not saying a hammer is the option best offered, but the expensive tools are actually versions of old tools. A good machinist can use a drill press to do the work that most use a milling machine for. The best cotter presses are just versions of C-clamps designed for specific pressure points. Just my experience. Smiles, MH

3alarmer 

...before I bought a dedicated tool for pressing cotters, I used a drill press vise and a socket. The drill press vise is as maneuverable as a c-clamp, but sturdier than the C clamps I own here.

bulgie 

Duly noted — I won't work on your bike! (I gotta ask though, how do you install or remove a crown race? Loosen a quill stem expander?)

I wouldn't like that to avoid assault with a deadly weapon, I have to use an inferior tool. Yeah I said it — the best press IMHO is inferior to a hammer, expertly wielded. I have a Var 07 but it's pretty much shop decor. After you tighten your cotters with whatever "proper" tool you like, I can get it in tighter with Mjolnir, and no damage done. I have done this test — use the Var and tighten the nut, then use the hammer and the nut is now slack, tightens a little more. You don't get that looseness in the nut if you reverse the order.

The super-brief peak force from a well-done hammer blow is higher than the static force you can get with a press.

I'm not trying to get anyone to switch to using a hammer. I agree that a good press is plenty good enough, and safer for most people who will never get enough hammer practice to get really good at it. That makes the press the best tool — for most people, tho not for me.

Mark B

Reynolds 

Sometimes I've used a combination of the 2 - the big C-clamp wouldn't be enough to loosen a stubborn cotter and a sharp hammer blow on it did the trick.

branko_76 

Mark B,

As someone who has been using a hammer daily for the past 40 years or so, I can appreciate a well placed hammer blow. Once, at the end of a work-week and after a couple of beers, we all took turns and I could drive a 16D coated nail into a Hem-Fir stud in 1-1/4 blows with a 22 oz framing hammer......so maybe I'm the wrong guy to be using a hammer anywhere near a Reynolds frame...

bulgie 

The human nail gun! Yeah, I've seen it done, very impressive. Before the invention of nailguns, I bet framers and roofers swung the hammer more times in a day than I did in a year. Talk about mastery.

rhm

Yup. And...

When removing a cotter, my favorite tool is a small vise made for use with a drill press. I put a socket (or some similar object) over the end of the cotter, tighten down on the vise until there's a fair amount of pressure pushing the cotter out. Then I bang on the vise with a hammer. One solid hit with the hammer, in the right direction, and the cotter pops right out. The hammer never touches the bike.

francophile 

I'll happily take it off your hands for $50!

I'm sure one of our two nearby co-ops would love to have one so they can stop calling me every time a cottered bike comes in the door. Hell, I'd love that too, save me some gas, although I'd miss the free parts-bin digging I enjoy every time help them out.

bulgie 

I know it's illogical for me to have this gigantic tool taking up space and not getting used, but I just like it. It's iconic. And effective for defending against home invasions. And I wouldn't want to deprive you of your the free parts-bin digs.

- Mark B