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End Bolt Plates


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Just wanted to ask the good people here if anyone knows of commercially available end bolt plates for concertinas? I mean the brass fitting in the bellows frame which the end bolt screws into. I've obtained a few pairs of old bellows one of which lacks all its plates, another has a couple damaged by overscrewing (?) and the third has the cheaper kind of fitting which is recessed into the bellows frame about halfway down the frame wall.

 

I'm sure David Leese sells old spares but I'm wondering has anyone found new commercially available alternatives which fit?

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Wim Wakker of Concertina Connection makes and sells them. You would need to check with him what the threads are - you may need to buy his endbolts too.

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and the third has the cheaper kind of fitting which is recessed into the bellows frame about halfway down the frame wall.

 

I'm sure David Leese sells old spares but I'm wondering has anyone found new commercially available alternatives which fit?

 

Oddly enough I've just received a full set of brand new endbolts and plates of the cheaper type Lachenal fittings you mention. The bolts are slightly larger in diameter than the original so a bit of drilling is required. A set of 12 bolts and 12 threaded plates from David Leese is £15 + p&p, no doubt he also has the screw on plates too but they would be more expensive for obvious reasons. It's always worth asking David about parts he doesn't list on the website as he often has just what you're looking for.

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Thanks Theo and Tallship....... I'm aware that David and Wim would have old plates / newly made bolts and plates, but I was trying to find out if there was any commercially available small fitting which people have found to work. It would be great to be able to walk into a local hardware store and buy a bunch of these rather than ordering them from abroad or being at the mercies of availability....

 

I know the endbolts are a problem insofar as I read somewhere recently there's no commercially available modern equivalent. To be honest I was a little surprised about this. I appreciate that the bolt has a kind of two stage set up - a threaded section commencing slightly below the head then a thinner bottom section which is threaded for the endplate. That being said I would have thought there must be some kind of modern instrument, fitting etc which called for a similar type of bolt, and therefore a corresponding plate??

 

The good thing is I have some spare old endbolts but it's the bolt plates which I'm looking for....

 

I have some nice pieces of brass and have half a mind to try and make a simple plate as an experiment. Has anyone had a go at making their own and if so how did they bore the threaded insert?

 

Michael.

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The problem with making your own is the thread. Many 19th century instruments predate the adoption (though not the invention) of standardised threads, that is, you could not walk in anywhere and ask for a x" nut and have it fit a bolt. Manufacturers made their own dies to their own pattern. It is possible to remanufacture bolts in old unique thread patterns if you find a competent toolmaker who can match the thread shape, pitch and tpi. Richard Evans can do this. Manufacturing captive nuts in similar patterns is only slightly more difficult.

 

Since Joseph Whitworth created the first standardised thread in 1841 (he also created the "thou" and worked on the Difference Engine amongs other things)the concept of a standard thread pattern has become universal, and there are many of them. Most more recent concertinas made in the UK probably use a thread called BA (British Association. I use 7BA myself.

 

If your concertina is old it is very unlikely you will find a tap for the size and any replacement will involve a lot of luck and someone like David Leese. Alternatively you will need to replace the bolt and the captive nut. The bolt may be able to be bought in a modern thread though it will not look "right" and the nut will have to be hand made by someone with the skills. These are not rocket science and I would say, have a go. Mark out your new nut carefully, centre punch the hole points for the screws, drill and countersink them, fit the nut to the bellows, reassemble the end and drill the exact tapping size for the thread you have selected through the existing hole in the end to line it up in the right place. Buy a tap of the right size, experiment until you can use it precisely, thread the hole.

 

Chris

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