Reed screw breakage.

[BrokenBox]

I am still trying to restore my poor old Rock Chidley and am stripping the reed pans to replace all the bent and curly valves.  However on the left pan (the only one I've tackled thus far) three of the reed clamping screws have snapped off whilst removing the reed frames. Admittedly I may have caught one screw with a screwdriver, but one screw simply fell off onto the table without being touched and one came away whist pulling the frame out with my fingers.

I wasn't expecting the frame screws to be so fragile, even after 170 years or so.

What do I do? Does anyone have spare Rock Chidley reeds? Are they interchangeable from other concertinas? Can I get replacement screws and keep the frames and tongues?

All advice welcome.

I didn't realise restoring a concertina would be such an emotional roller coaster...

 

[Alex West]

BrokenBox

 

The clamping bolts can often be interchanged from other scrapped frames.  If you don't have any, then what I've done in similar situations is drilled out the old broken bolt and drilled and tapped for a 10BA or 9BA bolt.

 

Whereabouts in Scotland are you?  I'm in North Ayrshire and might be able to assist with advice if nothing else

 

Alex West

[wschruba]

For very old/precious things like this, it's a good idea to 1) grind a screwdriver to fit exactly, and 2) apply heat before trying to remove them.  Touch a soldering iron to the screw for 10 seconds or so, and allow to cool.  This can help break corrosion. 

 

A hypo applicator can be used to touch the threaded bits with a small amount of penetrant. 

 

Obviously, don't use penetrant on wood...

[d.elliott]

I do the same as Alex, drill out and tap oversize with a modern thread. Obviously, getting the companion screw out can be fun, but if you remove the reed tongue it is not too bad.

[Lappy]

This is in North Carolina:

repair@squeezeboxgarage.com
 He might have spare replacements.

[BrokenBox]

@d.elliott, @Alex West I've managed to remove the broken ends of the screws from the frames. Would either of you gentlemen happen to know what size they might be to get replacements? I've measured the outside diameter and thread pitch the best I can and the nearest (but not quite...) standard I can find is 1/16" BSW.  I think also BSW may have been the only standard thread at the time the concertina was made? But I'm not sure the bolts are standard anything.

It's a Rock Chidley, serial 3631 and 3634; I'm guessing 1858-ish.

Edited May 18 by BrokenBox

[alex_holden]

16 hours ago, BrokenBox said:

@d.elliott, @Alex West I've managed to remove the broken ends of the screws from the frames. Would either of you gentlemen happen to know what size they might be to get replacements? I've measured the outside diameter and thread pitch the best I can and the nearest (but not quite...) standard I can find is 1/16" BSW.  I think also BSW may have been the only standard thread at the time the concertina was made? But I'm not sure the bolts are standard anything.

 

I think they are probably not anything recognised as a standard today. If anything it might have been an obscure size used by 19th century Swiss clockmakers; one of the ancestors of the BA standard. As @Alex West said, retapping it 10BA or going up to 9 BA might work.

[Chris Ghent]

Early concertinas predate standard threads and  because you couldn’t buy them manufacturers made their own. When the die wore out or broke they made another but it would not necessarily match the broken one.  
 

A good machinist can measure the old one, or the other one in the frame but if you are not that person or know them, as the others said, drill and tap a slightly larger hole for some buyable standard thread. 

[d.elliott]

I tap out with an appropriate BA tread and fit a standard BA set screw.

 

 

[4to5to6]

I got a small quantity of new BA threaded screws from Steve Dickinson as spares.  They are most likely BA threads…  BAtaps and dies are readily available on Amazon.  As suggested, one can always tap it out slightly oversized and use a small metric or SAE bolt.  Go slowly… backing out every quarter turn then forward again to clean the chips out… these taps easily break.