cotter pins

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hubgearfreak
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Re: cotter pins

Postby hubgearfreak » 2 Apr 2010, 11:47am

Mick F wrote:1. file the flat a little to make the threads poke out far enough - too thin and the threads came out too far. Either way, there must be a specific/definite/correct size for them
2. Also:
What material would be best?
SS would be too hard?
Brass would be nice, but not tough enough?


i don't have a definitive answer, but here's my thoughts. 8)
1. i'd imagine that some are too fat, and some too thin because the size required depends on your combination of cranks & axles. so, err on the side of the too fat with the option of filing.
2. something softer than the crank & axles, that can be filed reasonably easily and if they don't come out later can be drilled. so, stainless and brass are both out

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Mick F
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Re: cotter pins

Postby Mick F » 2 Apr 2010, 12:01pm

Thanks for that Hubbers.
Plain steel will rust. Chroming is what costs the dosh. Surely, SS or brass won't jam tight so won't need to be drilled to remove?
I dunno, but I bow to anyone's knowledge on this.

I just remembered, after my last post, that I have the RSW16 sat sitting in the summerhouse. I wandered out with the required spanner and big hammer, to take out a cotter pin. To my absolute amazement, the LH pin came out VERY easily with only a single blow of the hammer. So now I have a pin in mint condition complete with its Raleigh Nut, I also have the cranks and BB spindle from Chopper.

All these bits I will take down the pub this evening to see what Paul may say. (after a beer or two!)
Mick F. Cornwall

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hubgearfreak
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Re: cotter pins

Postby hubgearfreak » 2 Apr 2010, 12:37pm

Mick F wrote:Surely, SS or brass won't jam tight so won't need to be drilled to remove?
I dunno, but I bow to anyone's knowledge on this.


that's the problem i reckon. if SS doesn't deform slightly to the shape of the axle and crank, it'll never be tight enough to not rattle/click in use. i'd much sooner use a brass one than a SS one for this reason.
having said that, brass would too easily lose it's thread when someone tightens it up, and very easily mushroom over when trying to remove.
some grade of the softest steel and plated is the only way, as far as i can see.

it's not knowledge, but just ideas. :wink:

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hubgearfreak
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Re: cotter pins

Postby hubgearfreak » 2 Apr 2010, 12:44pm

Mick F wrote:All these bits I will take down the pub this evening to see what Paul may say. (after a beer or two!)


when you see paul, ask him what woodruff and similar keys are made of. AFAIK, they're deliberately made of softer metal, for two reasons
1. to not damage the parts they hold together
2. to deform slightly for a good fit

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Greybeard
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Re: cotter pins

Postby Greybeard » 2 Apr 2010, 1:05pm

Mick F wrote:
GrahamNR17 wrote:Is there a "Standard Size" or "Standard Design"??

Also:
What material would be best?
SS would be too hard?
Brass would be nice, but not tough enough?


Generally 3/8th for Imperial and 9 mm for metric (not a vast difference but can sometimes be more than enough).
They are not totally straightforward to make as the threaded portion does not come out of the middle of the pin - it is offset. That makes it a bit more inconvenient to make on a lathe as the stock material needs to be set up off-centre. That's one reason why I cheated a bit with the ones I made - which I think are also neater.
The grade of SS can make a difference - simply for the machining. Some grades are incredibly hard to deal with and rapidly jigger cutting tools if not set up correctly. I have some free-cutting stainless that cuts pretty much as easily as standard bar-stock steel.
I can think of no reason why brass wouldn't work equally as well.

If you do get stuck Graham and want a pair making like I did for Christine, I can do that for you. I assume that you'll need them for an English bracket. I have some old Rudge and Raleigh cranks and axles (1950's) - I can machine them to fit those and hopefully the end result will be near enough for your machine. I'll PM you with my phone number if you want to chat.
Steve

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Mick F
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Re: cotter pins

Postby Mick F » 3 Apr 2010, 12:31am

Any road up, me and Paul had a chat.
"304 Stainless Steel" was his suggestion.
He said that he would have a think about CNC, and that he would give me a price for a 100, 500 or even a 1,000 production run.

Stand by for info!
Mick F. Cornwall

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robbo
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Re: cotter pins

Postby robbo » 4 Apr 2010, 12:23pm

If I was making cotterpins, price no object, I would use aluminium bronze.

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Mick F
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Re: cotter pins

Postby Mick F » 4 Apr 2010, 1:30pm

Ali bronze?
Why?

Not that I'm criticising or questioning your judgement. Just curious.
Mick F. Cornwall

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hubgearfreak
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Re: cotter pins

Postby hubgearfreak » 4 Apr 2010, 1:37pm

wouldn't that electrolyse itself solid to steel cranks, like seatposts in steel frames do?

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Re: cotter pins

Postby GrahamNR17 » 4 Apr 2010, 1:42pm

hubgearfreak wrote:wouldn't that electrolyse itself solid to steel cranks, like seatposts in steel frames do?

Almost certainly would. At least it would be easier to drill out than a steel pin :roll:

Cotterless, that's the answer 8)

I yate cotterpins :evil:

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hubgearfreak
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Re: cotter pins

Postby hubgearfreak » 4 Apr 2010, 2:03pm

GrahamNR17 wrote:Cotterless, that's the answer 8)


burn the witch :P

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Mick F
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Re: cotter pins

Postby Mick F » 4 Apr 2010, 9:01pm

I spoke to Paul today down at the boozer this lunch time, and asked him about ali bronze. He wrinkled his nose and asked why ali bronze? He said it had good wear properties and is used as bearings.

He has a book, circa 1880, all about the properties and uses of metals and alloys . I asked him to photograph all the pages and produce a .pdf so we could all read it. He told me to push off.
Mick F. Cornwall

GrahamNR17
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Re: cotter pins

Postby GrahamNR17 » 4 Apr 2010, 9:05pm

Mick F wrote:He told me to push off.

:lol: :lol: :lol:

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Mick F
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Re: cotter pins

Postby Mick F » 6 Apr 2010, 10:41pm

whoops wrote:3/8" Cotterpins for Vintage, Classic & Antique Bicycles. Getting increasingly difficult to find and now an endangered componant due the the manufacturer closing down in 2008. Limited stocks. Available in Bright chrome, file them to suite if needed.
Sold as a Pair. Our Price: £8.00

Is it my imagination, but isn't this a tad expensive
or am i living in the past?


I received an email from Paul today:
Paul Pridham wrote:Hi Mick,
Looked at those cotter pins, I don't think I could do much better than this chap on ebay:
http://cgi.ebay.co.uk/Standard-Cotter-P ... 3ee36400ed
Unless we were making thousands!
Paul


and another .......


Perhaps £3.99 a pair is the figure required?
A little better than the OP - hopefully.

It all seems very expensive just for a wedge and a nut.
Mick F. Cornwall

GrahamNR17
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Re: cotter pins

Postby GrahamNR17 » 7 Apr 2010, 8:10am

I'd pay good money for good quality. Would I pay 8 quid a pair? For known good stuff, yes. Would I pay 8 quid to someone on ebay? No way!