Another stuck cotter pin. Keep hammering or drill it out?
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That would have been more convincing if the guy had rotated the crank 90 degrees to allow the penetrating oil to get into the pins surface.
And the vice set so the crank is at its centre.
Yellow Saddle
Guru
- Location
- Loch side.
[QUOTE 4516337, member: 9609"]Good way to break a vice, I certainly wouldn't be doing that with mine - he had it in the end of the jaw as well - I was cringing watching that[/QUOTE]
I had exactly the same tingling feeling down my spine when I saw that. I think it was a proper garage hacker who made that video.
[QUOTE 4516337, member: 9609"]
If you could get it supported on the end of a RSJ or a blacksmiths anvil then thump it with the head of a 10 lb sledge it would have probably popped out first go. Getting it onto a solid base is all important.
And I don't mean swinging a sledge at full length, I just mean holding it close to the head and thumping it - One thing that I have never quite understood when doing a job like that is; why would a 10 lb lump swung at a speed of 5 be more effective than swinging a 2 lb lump at a speed of 25 - they would both deliver the same energy but I could almost be certain the heavier lump would do the job.
[/QUOTE]
I agree with this observation as well. As to the question of the heavy vs light hammer. It has to do with the rebound. A lighter hammer rebounds and thus takes back energy to bounce back after the collision. The heavy hammer makes the cotter move.
As for penetrating oil. I am yet to see an application where it actually penetrates and loosens a tight anything. It works as a bit of a lubricant if there is a capillary in there (read: gap) for it to travel along. But for frozen bolts, seatposts etc where there is no gap between the items it is completely useless. I would like to see someone do a proper experiment - maybe Mythbusters - to finally prove that it doesn't work.
I had exactly the same tingling feeling down my spine when I saw that. I think it was a proper garage hacker who made that video.
[QUOTE 4516337, member: 9609"]
If you could get it supported on the end of a RSJ or a blacksmiths anvil then thump it with the head of a 10 lb sledge it would have probably popped out first go. Getting it onto a solid base is all important.
And I don't mean swinging a sledge at full length, I just mean holding it close to the head and thumping it - One thing that I have never quite understood when doing a job like that is; why would a 10 lb lump swung at a speed of 5 be more effective than swinging a 2 lb lump at a speed of 25 - they would both deliver the same energy but I could almost be certain the heavier lump would do the job.
[/QUOTE]
I agree with this observation as well. As to the question of the heavy vs light hammer. It has to do with the rebound. A lighter hammer rebounds and thus takes back energy to bounce back after the collision. The heavy hammer makes the cotter move.
As for penetrating oil. I am yet to see an application where it actually penetrates and loosens a tight anything. It works as a bit of a lubricant if there is a capillary in there (read: gap) for it to travel along. But for frozen bolts, seatposts etc where there is no gap between the items it is completely useless. I would like to see someone do a proper experiment - maybe Mythbusters - to finally prove that it doesn't work.
[QUOTE 4516331, member: 9609"]And I don't mean swinging a sledge at full length, I just mean holding it close to the head and thumping it - One thing that I have never quite understood when doing a job like that is; why would a 10 lb lump swung at a speed of 5 be more effective than swinging a 2 lb lump at a speed of 25 - they would both deliver the same energy but I could almost be certain the heavier lump would do the job.[/QUOTE]
Your assumption about the kinetic energy is wrong, in fact the kinetic energy of a mass m moving at velocity v is
which means that the lighter, faster moving hammer has much more energy.
Having said that, I've no idea which would be more effective in removing a cotter pin. I don't think I've removed a cotter pin since I was a schoolboy and that was a long time ago. I don't remember what I hit the pin with but I do remember my physics.
Your assumption about the kinetic energy is wrong, in fact the kinetic energy of a mass m moving at velocity v is
which means that the lighter, faster moving hammer has much more energy.
Having said that, I've no idea which would be more effective in removing a cotter pin. I don't think I've removed a cotter pin since I was a schoolboy and that was a long time ago. I don't remember what I hit the pin with but I do remember my physics.
Drago
Legendary Member
- Location
- Suburban Poshshire
You want to try Rost Off Ice Mr Saddle. It isn't universally successful, but when it does work you can head the 'crack' as bits contract and start to let go of one another.
ChrisEyles
Guru
- Location
- Devon
I've never been able to remove a cotter pin with a hammer, despite working with hand tools a lot in my job and giving it some serious welly. Every single one's needed the vice and socket treatment, and I've not yet had one I couldn't get out this way (touch wood!). It's one of the many excellent tips I'm grateful to this forum for.
skudupnorth
Cycling Skoda lover
- Location
- Astley,Manchester
Just seen this thread and it brought back so many "good" memories of stuck cotter pins 
Glad you sorted it in the end
Glad you sorted it in the end
Had a seized cotter pin for my current project bike. I decided that although keeping the cotter pin in would keep it "vintage", I'd rather use a square taper crankset. Angle grinder through the crankarm got it off, and I just replaced the axle, using the existing cups, it being french thread this was the easiest option.
You will have a Raleigh bottom bracket in that so that means not only 26TPI threads but I believe (I never actually measured one) they are a wider shell as well - 71 or 73mm IIRC.
You will struggle to get a replacement axle that wide as most are for 68mm shells. One possible solution I have considered but never had any reason to try is to find a bit of steel pipe of the right diameter and cut the axle in the middle and push one end up the pipe, cut pipe to correct length and push the other end of the axle up the pipe and weld it all together. I would use a traditional arc welder with a proper "steel" rod for welding this type of thing. Obviously you need to cut it very accurately, make sure the ends are cut square and make sure it is in alignment.
Personally, I'd just keep the cottered crank. It's original, Raleigh chainwheels were good quality and wear very well and properly installed cotter pins should give no trouble.
The trick with these is to realise the nut is only to hold it in place and the thread is not strong enough to pull the cotter into place. They need to be pressed or hammered in and then tighten the nut. The reason yours was so difficult to get out was probably because the bike was ridden with it loose and the pin bent.
You will struggle to get a replacement axle that wide as most are for 68mm shells. One possible solution I have considered but never had any reason to try is to find a bit of steel pipe of the right diameter and cut the axle in the middle and push one end up the pipe, cut pipe to correct length and push the other end of the axle up the pipe and weld it all together. I would use a traditional arc welder with a proper "steel" rod for welding this type of thing. Obviously you need to cut it very accurately, make sure the ends are cut square and make sure it is in alignment.
Personally, I'd just keep the cottered crank. It's original, Raleigh chainwheels were good quality and wear very well and properly installed cotter pins should give no trouble.
The trick with these is to realise the nut is only to hold it in place and the thread is not strong enough to pull the cotter into place. They need to be pressed or hammered in and then tighten the nut. The reason yours was so difficult to get out was probably because the bike was ridden with it loose and the pin bent.
According to Sheldon the difference is the thread pitch and the axle length varies from 71 to 76mm. It is possible to get replacement axles of the correct width, I had a look on ebay and there appear to be a few available, you'll need to measure the shell width and work out what length axle you would need in combination with your chosen crankset.
http://www.sheldonbrown.com/raleigh26.html
OP
OP
Brand X
Guest
Thanks Tyred and SI_C, I would like to swap the old steel crank for something a bit lighter, those crank arms are heavy old lumps. Also, I discovered I'd made a bit of a boo-boo when I threw the old broken cotter-pins away: New cotter-pins have to be filed-down to the correct thickness and angle to make them fit, for which it's best to have the original ones as a guide. Oops.
ChrisEyles
Guru
- Location
- Devon
If you do decide to re-use the old crank then filing down new cotter pins isn't hard (use that handy vice to clamp them while you file). Dry fit them occasionally while you're filing and you can pretty easily tell when they'll do the job, it doesn't seem to be an exact science.
