smontanaro 

Warning: I have really never messed with cottered cranks before.

I have a Stronglight 52 cottered crank for my Automoto. It didn't come with a spindle, so that held me up for a bit. I think I have that problem solved now (some Raleighs which might be too long, but fit the holes in the crank). Onto the cotters...

I bought a bunch of cotters from eBay a few months ago, anticipating this step, because the cotters which came with the crank were really messed up. I have a selection of 9mm and 9.5mm cotters. The 9mm items are a very sloppy fit. The 9.5mm items are just a bit too snug. Looking around the net I didn't see any "specification" for cotter sizes. The 9.5's would probably make for a never-to-be-removed interference fit if I pressed them in (I do have a nice cotter press though...) Am I supposed to keep hunting for higher quality cotters or should I just sand/file down a pair of 9.5's until they are a slip fit?

juvela

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wedgebolt diameters depend upon national origin of machine

italy: 9.0mm

france: 9.0mm

britain: 9.5mm

nippon: 9.5mm

if your verot model 52's originally came on a brit machine the wedgebolt bores should be for 9.5mm

if originally came on a frankish product bores should be for a 9.0mm pin


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smontanaro 

Thanks. I will bookmark this post for future reference.

I don't know what sort of bike the crank was originally installed on. I will throw you a curve. The bores certainly seem closer to 9.5 than 9.0 (British?), but it seems the pedal threads are French.

Are sloppy cotters okay, or should i reduce the diameter of the 9.5's? Alternatively, are cotters normally a loose fit or a slip fit?

63rickert

Skip

Measure your eBay cotters. They will be undersized. If you want full sized cotters go to Mark Stonich who sold you the press. Or go back to eBay and try to be certain you are buying vintage. There also exist oddball random sized cotters for mopeds and proprietary uses. Conceivably you might have some those.

From here don't know if your Stronglight 52 is English or French. If you try to put a French crank on an English spindle that is a 0.005" sloppy fit. It can work. The way to make it work is to mash and deform the cotter with a press. The cotter is much softer metal and the press is stout enough to deform metal and plug the hole. A full sized 9.0 cotter is plenty to make French/English work the way it is supposed to. Automotos from Sears - which yours is - were thrown into the wild back in the 1950s with zero parts support. Replacement spindles were usually English and no one had problems.

Cotter should be used as a wedge clamp. It is not a plug. Deformed metal might work for a few years, eventually it fails and undersized cotters make that happen quicker. File the cotters a lot. Get a flat going from end to end. If you overdo it the cotter will go too deep. You can washer up the threaded post, maybe, or you can keep the overfiled cotter as a sample.

When you have a filed cotter that fits you will feel the wedge clamping with just your hands. Couple taps with hammer and a drift pin will set the cotter. Same couple taps will remove the cotter. After a lot of experimenting with this and finally getting good information from mechanics in their 80s and 90s who remember life before the Var #7, I rode my cotters for over a year with just a couple hammer taps and no nut on the threaded side. It works. Get a good drift pin, do not omit.

The chances you have a crank with a bad pair of cotter holes is really remote. Even running loose mismatched cranks and sacrificing cotters while trying to figure this out it is the cotters that wear. Old Stronglight is good forgings and they were accurate. Your eBay pins are undersized.

noobinsf 

Cotters are not supposed to wiggle around, so it sounds like greasing the 9.5’s should let them fit in as they need to. Unless you have the old cotters for reference, you may need to fiddle with file a bit to make sure your pins will sit right when pressed in. I only filed cotters once, and I had the old ones to guide the angle, so I’m not sure how to make it right with trial and error, but someone else will surely chime in.

63rickert

I type slow and missed your #3. Everyone is familiar with French cranks that have been tapped to 9/16". Retapping the cotter bore hole is an odd one but could have happened. Will a 3/8 drill bit go through? 9.5mm is 0.374". Drilled accurately it should work.

63rickert

Cotters are an easy slide fit until the wedge connects to the flat on the spindle. Keep grease away from the filed flat and the spindle flat. Everything else should be greased but err on side of dry if you think anything is going to the business flats.

Crank on spindle is the one where a significant error on loose side could occur and would not so much matter.

Cheap Chinese cotters are 0.1mm and even more undersized and they do work for a while if you seriously mash them with a press. You could reduce the size of your cotter and get away with it. Better to get it right and have the easy maintenance of a well working cotter.

63rickert

Your Raleigh spindle is 5/8" or 0.625". If the Stronglight is French it is a 16mm spindle hole, which is 0.630". It is a loose fit and you can't miss it. It will be OK. If you have a French crank the cotter hole should be right on 9.0mm. If it is bigger than 9.0 someone messed with it. 3/8" is 0.375", 9.5mm is 0.374. Use a 3/8 drill bit to measure what you have.

9.0mm = 0.354"
9.5mm = 0.374"
23/64 = 0.359"

Few of us have a 23/64 drill bit but someone might. Once upon a time Raleigh sold a 16mm drill bit for converting English cranks to French. Old parts and weird stuff happens.

juvela

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binding of 9.5mm pin

there can somtimes be a burr at the inner end of the hole for the wedgebolt where it meets the hole for the spindle

this can be due to manufacturing tolerance/error but is more commonly due to someone pedaling the chainset with a loosened wedgebolt

a tapered hand reamer or half-round or round file can be employed to deburr that area

suggest to run one in and then check again...


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Mad Honk 

You won't need a violin to install to cotters. A couple of good files will be your friends for the job. Smiles, MH

Moe Zhoost

1) As others have said, cheap cotters are crap. Most of them I've seen are not even round, They are slightly oval because the flats are deformed mechanically rather than machined. Buy proper ones from Mark Stonich.
2) I've never used a new cotter that did not need a bit of filing first. You can do this freehand with a file, or use a jig. The goal is to keep the taper flat.

smontanaro 

Thanks for the suggestions folks. I still don't know exactly what I have, and it seems clear the Raleigh spindle has the wrong offsets left and right, but the bottom bracket and crank are installed. I hit the inside of the bores on the crank arms with a small sanding drum attached to my Dremel. Took maybe 30 seconds per arm, and left a couple little piles of schmutz on the workbench, so I guess that was the barrier. The Raleigh spindle is wrong for the application (too much offset right, not enough left), but it will be good enough for a spin around the block once I get it rolling.

juvela

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the Sir Wally model 16GC spindle is an odd duck

the factory employed it for both single and for dual plateau drive trains


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smontanaro 

Yes, that's what I've got. Now that it's in use though, it will give my source (Billy) an idea of what to look for in his stash. My guess would be 4-ish less offset on there right, 2-ish more on the left. I'll measure the space between the inner chainring and the chainstay to get a more precise idea of what i have to play with.

Mad Honk 

As always my co-op may have something that will work for you. But the dimensions need to be around for me to do a search. Smiles, MH

iab

What's the BB width? I have spindles for 70mm. From your description, sounds like you have a 68 spindle in a 70 BB shell. I could be very very wrong.

smontanaro 

Thanks. It's a 68mm shell. My understanding is the Raleigh spindle is for a wider shell. Billy Ketchum should be able to fix me up with something more suitable.

iab

Well that's weird. A wider spindle should have plenty of clearance on the non-drive.

smontanaro 

Correct, though as juvela noted, the Raleigh 16GC spindle (what i have, how'd he know that?) is weird.

I've got two more on the workbench. I'll measure them today.

63rickert

As long as you are not hitting the chain stay with the left crank you're fine. Not like it will settle in and get closer. Looks like chainguard clearance on right.

Also looks like old brilliant French purple under the BB. Doesn't get a lot of sun underneath.

juvela

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the 16GC Raleigh spindle is made for use in the Raleigh 71mm shell

"most" spindles for 70mm shell have bearing centres of 57mm

"most" spindles for 68mm shell exhibit bearing centres of 55mm

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if you would like to be kitted for future cottered chainset work strongly recommend acquisition of a cotter vise for filing the flats

allows one to clamp the fitting securely while leaving both hands free for tool use

several makers have produced them

here is the VAR Nr. 371 for example -

​​​​​​

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it can happen that when one gets everything together a slight mis-registration of the arms is perceived in the range of one to three degrees

this is a difference in the effective "cut" of the cotter pin flat

it is necessary to disassemble things to examine the "cuts" (flats) on both pins

one will be slightly lighter than the other

a few strokes of a file on the pin with the lighter cut will put things right

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in cases where a large mis-alignment can be seen in the range of ten to fifteen degrees it is the case that one pin has been mounted with the head leading in the crank rotation while the other has been mounted with the tail leading in the crank rotation

this is frequently seen in the case of used machines

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smontanaro 

Sorry for the radio silence. It took me a while to get back to this. I tore down the bottom bracket to check a couple things. One, it is British threaded (not what I would have expected) and the shell measures 68.1mm.

I measured the Raleigh 16GC spindle as well. It measured 132mm tip-to-tip. the distance between the bearing races is 55mm, with 45mm sticking out to the drive side and 33mm to the non-drive side. I measured a gap of about 10mm between the inner chainring and the chainstay. Ideally, I think something like a 130mm spindle with 40-41mm on the right and 35-36mm on the left would work much better than the Raleigh-specific spindle.

juvela thanks for the recommendation of a cotter vise. I don't really intend to get neck deep in alligators cottered cranks, so I will take a pass on this (unless simply falls into my lap). Building the Automoto is more an exercise in baroque components than a new career. Mad Honk if you've got something, let me know off-list. (I will also check the local co-ops in Chicago, though I really doubt they will have anything this esoteric.)

Mad Honk 

Skip,
I'm guessing you want to borrow this for all of the fitting and retro-fitting of the spindles you are going to try:

Not anything special but pretty darned good at installing the cotters in a solid fashion.
I guess if you need this I can try to do a road trip from Bloomington to either Niles, or maybe Chi-town to lend it to ya and bring along a frame for you to play with. Smiles, MH

smontanaro 

Thanks Mad Honk. I've got the Bikesmith Design item, a slightly older version of the one they sell now (no rounded corners).

Road Fan

Skip, you may have this info by now, but check out the website of Mark Stonich, bikesmithdesign.