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-   -   How to remove lockring on very old (French) chainring (https://www.bikeforums.net/bicycle-mechanics/907639-how-remove-lockring-very-old-french-chainring.html)

mechantbruce 08-15-13 05:14 PM

How to remove lockring on very old (French) chainring
 
1 Attachment(s)
Hi,

I am overhauling a very old french bike, and really want to take absolutely everything apart.

The chainring is attached via a lockring as can be seen in the photo below;

http://bikeforums.net/attachment.php...hmentid=334932

-- Do I remove the lockring anti-clockwise?
-- What is the best tool to try and remove it?

it has too large a circumference for any of my lockring spanners, I am using Hozan C-203 Lockring Pliers but after several days and lots of WD40, I cant get the lockring off (I think it did move it a bit (anti-clockwise), but it seized up tight again (hence the question about clockwise/anti-clockwise).

Any suggestions?

bikeman715 08-15-13 05:26 PM

It should come off counter clockwise . WD-40 not a very good oil for this , try something like PB Blaster in it place and it might take a few days for it to work in . If you have a vise use it to hold the crank arm as you work on the locking ring .

lee kenney 08-15-13 05:29 PM

That is a puzzle, is the chainring threaded on ? Like a track hub, or is the lock ring like a ashtabula crank? Perhaps clamping lockring in a vice using soft jaws, then use a cheater bar over crank arm to loosen lock ring . Cottered cranks are fun !

dsbrantjr 08-15-13 05:42 PM

"try something like PB Blaster" or Kroil.

cny-bikeman 08-15-13 06:06 PM

The French did not even make fixed cups reverse thread, so I'm betting it's normal. Unless you are planning to chrome the chainwheel I don't see any reason to disassemble. Also, even if the right size a lockring tool is generally not appropriate for something that old and frozen on. I suggest you clamp the arm in a vise (horizontally) and take a hammer and flat punch to the lockring notches after treating with PB Blaster.

mechantbruce 08-15-13 06:40 PM

Thanks for the replies, as per normal, the products recommended (PB and Kroil) are not available in France. I can get an 8oz can of Kroil from USA for 11$ plus 55$ postage, and I may just do that, but I have just been reading a bunch of threads saying auto transmission fluid mixed with Acetone is better than all the commercial penetrating oils, so (presuming I can get acetone here) I might try that first;

**Machinist's Workshop magazine tested penetrants for break out torque on**
**rusted nuts with significant results!**

**They arranged a subjective test of all the popular penetrants with the**
**control being the torque required to remove the nut from a**
**"scientifically rusted" environment.**

***Penetrating oil ...... Average load***
**None ....................... 516 pounds**
**WD-40 ................... 238 pounds**
**PB Blaster .............. 214 pounds**
**Liquid Wrench ..... 127 pounds**
**Kano Kroil ............. 106 pounds**
**ATF-Acetone mix....53 pounds**

**The ATF-Acetone mix was a "home brew" mix of 50 - 50 automatic**
**transmission fluid and acetone. Note the "home brew" was better than any**
**commercial product in this one particular test. Our local machinist**
**group mixed up a batch and we all now use it with equally good results. **
**Note also that "Liquid Wrench" is about as good as "Kroil" for about 20%**
**of the price.**

cny-bikeman 08-15-13 06:53 PM

You can also try a propane torch, though preferably after removing most of anything you've used to loosen things up. I still recommend just leaving it.

JohnDThompson 08-15-13 08:01 PM

Geez. I'd just leave it alone. What do you hope to gain by removing it? That's a lovely crank and I'd hate to ruin it with ham-handed attempts to separate the ring from the arm.

mechantbruce 08-16-13 02:24 AM

"Geez. I'd just leave it alone. What do you hope to gain by removing it?"

Thats a very good point, and I agree its not necessary to remove it,,, but...

-- its a learning experience. I would like to know I can remove these if I need to (or not I suppose)
-- I want the satisfaction of knowing I have *completely* stripped the bike and every part is reassembled with grease or oil, and can be serviced if needed.
-- If I can find a smaller chainring, I would love to lower the gearing (its VERY hilly round here (French Pyrenees)
-- The photo is actually of a practice chainring/crank. I bought a whole box of rusty parts on ebay for 20euros and there were a couple of these in there. I am learning on one of these, and if I think I can remove the one mounted on the bike I am restoring without buggering it up, then I will have a go.

Thanks, I appreciate all the help and suggestions. I have benn working on it with the Hozan C-203's while it is in a vice (with soft jaws fitted). I will see if I can fix the chain-ring and rotate the crank, and if not will try to fix the crank and hammer at the lockring with a punch. I will wait until I have acquired and mixed up some ATP/Acetone first though.

Cheers,
Bruce.

mechantbruce 08-22-13 03:39 PM

Just in case this ever helps anyone... I got the lockring off.

I hammered it counter-clockwise a bunch with a punch and it moved an inch or 2 and then stopped.

I then had the good fortune of meeting someone local who really knows vintage french bikes, and he showed me that they are reverse-threaded.

I got home, and was able to remove it clockwise with just the Hozan lockring pliers. (it had been treated for a few days with my homemade penetrating oil (see above), not sure if that helped; but turning it in the correct direction certainly did).

Lesson learned :)

keidal 04-23-15 01:45 PM

In my experience all French chain wheel lock rings are reverse threaded, so punch clockwise to remove.
There are very few [fine] threads on the lock ring and if you wire brush around the seating and the outer surface where the threads are; then liberally apply paraffin, this will do the trick. There is no need to use a vice.
Even better if you use a short length of 6mm hard brass rod as a punch, with a hammer of course !


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