Any bush mechanics out there? I need to expand the end of a pin.

[slowmotion]

Personally I would just spend the £20 on a replacement FD. I would be worried that whatever I bodged would not last. Either that or go to a 1 x 10 setup. I am amazed that you have lasted like this for 7 months.

The mech was only six months old and had been clamped at the correct torque. I'm not going to bin it when it can be fixed for pennies.

 

[Milkfloat]

The mech was only six months old and had been clamped at the correct torque. I'm not going to bin it when it can be fixed for pennies.

Warranty job then?

 

[slowmotion]

How long does it need to be ? You can buy the spring pins in various lengths and have a few spare.

http://www.ebay.co.uk/itm/SPRING-RO...hash=item2a13d78687:m:m1vohBrxOVtvHqTj_Daju3g

The pin is about 15mm long and had two or three turns. If the old pin sheared, I'm not entirely confident that a new pin of the same type will hack it either. If I can keep a stainless pin in place, I'm reasonably confident that it'll be a better solution.
Ah, the arrogance born of ignorance!

 

[screenman]

Just peen it over as mentioned earlier, not that hard to do and should work. Nothing ventured and all that stuff.

 

[slowmotion]

Just thoughts on the previous suggestions....
Marine grade SS, I suspect you will find it quite difficult to dot / pin punch the ends to bell it out...stainless is very very hard.
Spring pins...do the two parts the pin is going through pivot or move individually from each other (does that make sense)..a spring pin is an interference fot that would lock the two parts together. I suspect it wouldnt work.

The hole in the hinged section of the clamp is a slightly larger diameter than the two holes in the fixed part, hence it can pivot freely. I take the point about working with stainless. I had to hand tap some holes in some stainless parts once. Utter misery. With a sharp punch and a big lump hammer, I reckon I should be able to spread the ends a bit if I come up with some fixture to clamp the workpiece.

 

[slowmotion]

Thank you everybody for you advice. I'm very grateful. The mech is over a year old now. I did look at the warranty option a few months back but it was a bit of a faff returning it to the Campagnolo agents. Besides, I like fixing things! I should have the stainless rod by post next week. I'll let you know how it turns out shortly thereafter.

 

[Venod]

The pin is about 15mm long and had two or three turns.

The spring pin/roll pins a quite tough & can be cut to length with a cutting disc.

If you want to peen the stainless, cut a piece so it rest on the bottom of the vice jaw when it is clamped in the vice with just enough protrouding to work with, peen the end to a nice mushroom shape, cut the pin to length allowing just enough to peen other end, insert pin, support already peened on something solid (vice) peen other end.

I would just stick a screw in.

 

[Levo-Lon]

How about fit the SS pin so its 3mm short and resin bond the ends?
The 1.5mm recess on each end should be plenty to hold the pin in place..



no need for a hammer or drilling SS which is Kin hard

 

[slowmotion]

How about fit the SS pin so its 3mm short and resin bond the ends?
The 1.5mm recess on each end should be plenty to hold the pin in place..



no need for a hammer or drilling SS which is Kin hard

That's a neat idea. I did consider using some kind of slip-fitting Loctite engineering adhesive but was concerned it might wick into the pivoting part. Using some kind of epoxy just as an axial end retainer is a possibility.

Actually, I could cut the pin 3mm short and ding the aluminium casting instead of the stainless!

 

[Levo-Lon]

Yes thats another good fix idea @slowmotion

 

[Absinthe Minded]

...stainless is very very hard.

Stainless steel isn't very, very hard. It work hardens, but it's not hard until you work it. Centre punching it will be easy.

 

[Profpointy]

Stainless steel isn't very, very hard. It work hardens, but it's not hard until you work it. Centre punching it will be easy.

nevertheless you'll concede it is fairly hard, and I suggest stainless-ness is not important on a oily derailleur so mild steel would be a better choice here

 

[Absinthe Minded]

I agree, mild steel would be a much better choice, but I still disagree that stainless steel is "very, very hard". Certainly not hard enough to resist centre punching, or a bit of deformation.

 

[Ian H]

Looking at the photo in the OP, I think it the parts spend all of their life stationary with respect to each other, moving only when the mech is first fitted or taken off, so a roll pin should be fine.

Further to this, I think that, as the clamp is tightened, the pin should be locked in place. A small amount of Locktite would ensure that. No need to do anything else.

 

[Venod]

I agree, mild steel would be a much better choice, but I still disagree that stainless steel is "very, very hard". Certainly not hard enough to resist centre punching, or a bit of deformation.

Purple text WTF