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Removing Copper key pivots (methods / experience?)

PostPosted: Thu Jan 01, 2015 2:38 pm
by RobSay
Afternoon all - It's New Year's Day ... what better way to start 2015 than taking a look at non-playing Reid chanter and working out what is needed to get it back in playing order.

So the chanter I have is a 9 keyed ivory and silver by James Reid. It has been snapped at some point and long since previously repaired (minimum 40yrs ago); the repair has now failed. In order to get a good look at the problem and the existing repair (across the middle B and down to the G# block at the rear) - I need to get the keys off.

There are eight key blocks - and only one pivot came out with a normal push-pin. The pivot that came out is silver .. the remaining 7 pins all appear to be copper wire. I've removed the layer of green slime from each but a firm push is not producing any movement, waggling the brass push pin is now biting into the copper wire. I used sufficient force on one pivot to bend the brass push pin.

Does anyone have any experience or suggestions on methods for freeing up these ~1mm copper pins?

Amongst the thoughts & advice I have had to date:
- vinegar (soft acid) to dissolve more of the goo (shouldn't touch the ivory)
- steel push pin (harder than brass)
- drill /dig out the copper slowly by hand (0.75mm bit)
- drill out by machine (0.75mm bit at high speed)

And to any aspiring pipe makers out there ... don't use copper for pins; too soft & too reactive :)

thanks

Rob

Re: Removing Copper key pivots (methods / experience?)

PostPosted: Fri Jan 02, 2015 10:27 am
by Julia Say
meths? Standard cleaner for the various sorts of goo that unused pipes develop. And an old toothbrush to scrub it in with.

HTH

Julia

Re: Removing Copper key pivots (methods / experience?)

PostPosted: Fri Jan 02, 2015 11:53 am
by Richard Evans
Yes, meths first... soak the whole thing overnight? A steel pin sounds a good idea, with a flat head- a pointed head would maybe make the soft copper spread. I think drilling out would be an absolute last resort. I'm glad it's not me doing it!

Re: Removing Copper key pivots (methods / experience?)

PostPosted: Sat Jan 03, 2015 7:50 pm
by RobSay
And here's a picture of what I'm dealing with:
JamesReidChanter.png
JamesReidChanter.png (246.43 KiB) Viewed 3114 times

Re: Removing Copper key pivots (methods / experience?)

PostPosted: Thu Jan 08, 2015 10:28 pm
by Francis Wood
An application of alcohol may possibly help in dissolving coagulated matter and in steadying the nerves. But for both those desired outcomes I'd have strong reservations about meths. It contains dye and with any prolonged application it may enter the surface of the chanter. Ivory has been used for millenia as a dye-friendly work material and readily absorbs colour.

The use of vinegar to soften and mould ivory is an ancient technique and for the present purpose, that too should really be avoided.

Removal of a firmly stuck axle is not without risk especially where force and chemistry are involved, and unless there are compelling reasons (preventing adequate key function) it is probably left alone. Further breakage would be an avoidable tragedy.

Francis

Re: Removing Copper key pivots (methods / experience?)

PostPosted: Fri Jan 09, 2015 10:15 am
by Julia Say
Colourless industrial alcohol, however, does not have the dye in. Yes, we have some.

Julia

Re: Removing Copper key pivots (methods / experience?)

PostPosted: Sat Jan 17, 2015 8:34 pm
by Mike Hulme
Just a thought...

Is the pin possibly tapered? I had a Reid Union Pipe chanter in for reeding and the key pins were a taper fit.

Mike

Re: Removing Copper key pivots (methods / experience?)

PostPosted: Fri Jan 30, 2015 4:51 pm
by RobSay
I had considered that tapering might be contributing to the problem and have been wary of this - however I don't think the copper will be a tapered pin (I think it really is just electrical wire).

My thought is that if our historical fettler has gone to the trouble of tapering the copper - they would have gone to the trouble of using brass or silver ... that's a working premise rather than a banker tho!

I did go looking for 'things that dissolve copper' and the answer was basically not very much ... and whatever you do use will take most other things with it. Aqua Regia came up (ha!) and a bunch of electrolysis methods - definitely putting that approach to bed and returning to contemplating mechanical means.

R

Re: Removing Copper key pivots (methods / experience?)

PostPosted: Sat Jan 31, 2015 9:30 am
by pipemakermike
Have you considered spark erosion?
http://en.wikipedia.org/wiki/Electrical_discharge_machining

I have used a spark eroder to remove broken thread taps in sizes down to M1.6 where the electrode is only Ø1.2mm. It isn't a quick process but it is very benign. A good local subcontract engineering company will often have one.