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PostPosted: Wed Nov 28, 2012 12:13 am 
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The Raleigh Arena was a dirt magnet :)

Shaun


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PostPosted: Wed Nov 28, 2012 4:58 pm 
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What?... All of them or just one in particular? :)


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PostPosted: Sat Dec 01, 2012 3:24 pm 
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Inspired by this I have just stripped down my Atom freewheel. Recently the pawls haven't been engaging properly so I have been riding another bike. It's off my Raleigh Royal and is the original freewheel but hasn't always been on the bike as I ran a 6 speed for a long while. It is the best part of 30 years old though.
When I stripped it down I found that one of the pawl springs has broken. It's made from like a small strip of brass possibly. I just wondered if anyone has tried making replacements and if so how was it done? Not holding out too much hope but I'd have a go if I thought it was possible.

Cheers,
Ian.


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PostPosted: Sat Dec 01, 2012 5:38 pm 
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I have had to make a new pair of pawls (for another freewheel, not the one shown above) but I confess I've never (yet) tried to make a new spring..

There's a few different methods of springing the pawls depending on manufacturer.. Sounds like you have a freewheel in which each pawl has it's own spring.. replacing it mainly depends on being able to 'unsecure' the remains of the broken spring and 'secure' a new one in it's place. Does that look possible? If it does, it may help to remove the other unbroken spring at the same time and use it as a model for the new one.

To make a replacement you need the right raw material, which is likely to come from... a spring! An old clock mechanism may yield something usable, an old set of engineer's feeler gauges could probably be cannibalised, giving the possibility of matching the new spring quite well with the old remaining one, or make a pair..

As I say, I've never done this, so I'm just brainstorming out loud about how I might go about it... and assuming, perhaps wrongly, that direct replacement springs are not available...

Post some pics. if you can.


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PostPosted: Sat Dec 01, 2012 5:46 pm 
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I've got the old springs out okay. They're like a flat metal strip. Somewhere in the garage I have a short strip of brass. I'll have a go at making a pair from that. The feeler gauge idea also sounds promising. I found a website (about boats I think) where someone is making new pawl springs from piano wire by wrapping it around a slim screwdriver and pinching it together with pliers. The method looks do-able for flat springs too so I might try that. The rest of the freewheel looks surprisingly good considering its age.
Cheers,
Ian.


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PostPosted: Sat Dec 01, 2012 6:06 pm 
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What you describe sounds like somebody making spiral springs?

If you've got the old springs out you are way ahead... IMO you do need to find the right material for the new ones, though... there is a thing called 'spring-steel', not sure if there is a brass equivalent?


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PostPosted: Sat Dec 01, 2012 6:27 pm 
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This is the fella. Probably about 12mm long. I just assumed it was brass because it looked brassy. this is the good one by the way.
Probably more trouble than it's worth. Just that it can't be more than 28 years old and I thought it would have been good for at least another 28!


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PostPosted: Sat Dec 01, 2012 9:06 pm 
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Thanks for the picture... That always makes things clearer!

This is a crazy world. Nobody needs reminding of it's countless frustrations...

I don't know if bicycles feature as part of a sane world, but if they do, then so do manufacturers that provide a spare set of springs and pawls with every freewheel... but if they did do that, how many of us would remember where we had put them 28 years ago?

Chances are that within 5 metres of you and me and everyone else reading this there is some barely used domestic appliance, and somewhere inside it is just the bit of steel you need to make a new pair of freewheel pawl springs, but where exactly is that bit of steel?

This repair is do-able I am sure with piano wire, which is spring-steel, but you would probably need to try a few different gauges of wire to get a satisfactory result. Somewhere near you is a fella who strings pianos. He throws old piano wire away all the time. When he restrings a piano he is left with many offcuts of brand-new piano wire of various gauges which he also throws away. But where exactly is that man?

Perhaps somewhere in those paragraphs is your raw material. While finding it, and working it, of course your mind, just like mine, is constantly saying: "This is more trouble than it is worth, I must be crazy..."

I was reading this last night: http://www.energybulletin.net/stories/2012-11-28/the-endangered-repairman It's not about freewheels, or even about bicycles, but it's kind of related...


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PostPosted: Sat Dec 01, 2012 9:31 pm 
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Believe it or not I have a friend who builds Harpsichords for a living. Next time I see him I will ask!

I have an old Triton Shower in the garage. Well, when I say old I mean about 10 years which is an age nowadays for an electronic item. The reason it is in there is because there are two relays which have failed (apparently a very common failure on that particular shower). I reckon that the springy contacts on those relays might just be the material I need! Might even encourage me to mend the shower while I am at it, lol.

You're right about remembering where things are though. About the time I got my Royal I also aquired my 1936 Hobbs of Barbican. It only had a single speed and I wanted gears!! Nothing too posh though so I bought a Sturmey Archer 4 speed hub. A fellow CTC member who had worked as a cycle mechanic stripped it and rebuilt it for me. He gave me some spare pawl springs for the future should I ever need them. To keep them safe (they are incredibly tiny) I didn't put them into my garage like everything else as I knew they would disappear. Can I remember where those pawl springs are? Can I heck as like. (Not that they would be suitable for this job, I'd just like to know where I put them).

Ian.


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PostPosted: Sat Dec 01, 2012 9:48 pm 
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There you go then...we're building circles.. :)

I save all the little springs out of disposable lighters. :oops:


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