10 replies to this topic

[conzertino]

I need to re-cut some threads for Wheatstone endbolts ( Aeola ). Anybody knows what exact thread they are and where to get a tap?

[Theo]

If original they are a non-standard thread and taps are not made. Your choices are: replace the bolt(s) with modern ones where taps are available, or look for a secondhand replacement nut plate.

[JimLucas]

I need to re-cut some threads for Wheatstone endbolts ( Aeola ). Anybody knows what exact thread they are and where to get a tap?

If original they are a non-standard thread and taps are not made. Your choices are: replace the bolt(s) with modern ones where taps are available, or look for a secondhand replacement nut plate.

As Theo says, they are a non-standard thread. I used to know the specs, but it should be possible to measure them... diameter, threads per inch (or per cm), thread depth. Dies can be made, but it would be a custom job and probably expensive.

BUT... I have such a die, made for me years ago by Steve Dickinson. I'm pretty sure I know where it is, though I'm not there at the moment. If I can find it and if you're not in a great rush and if I can make it to your concertina weekend later this month (my schedule is still in flux), I'll be happy to bring it with me so that you can tap a few "nuts". (For what I hope are obvious reasons, I don't want to sell it or even ship it.)

[conzertino]

I need to re-cut some threads for Wheatstone endbolts ( Aeola ). Anybody knows what exact thread they are and where to get a tap?

If original they are a non-standard thread and taps are not made. Your choices are: replace the bolt(s) with modern ones where taps are available, or look for a secondhand replacement nut plate.

As Theo says, they are a non-standard thread. I used to know the specs, but it should be possible to measure them... diameter, threads per inch (or per cm), thread depth. Dies can be made, but it would be a custom job and probably expensive.

BUT... I have such a die, made for me years ago by Steve Dickinson. I'm pretty sure I know where it is, though I'm not there at the moment. If I can find it and if you're not in a great rush and if I can make it to your concertina weekend later this month (my schedule is still in flux), I'll be happy to bring it with me so that you can tap a few "nuts". (For what I hope are obvious reasons, I don't want to sell it or even ship it.)

I sure hope that you can make it ;-) I have a set of Lachenal nut-plates, but they seem to have a different thread!?

[Geoff Wooff]

I will have a look closely at my Wheatstone screws and measure them up, as I recall that they are not that different from something that was standard during the earlier part of last century. In the Vintage Car and Motorcycle restoration magazines there are people who specialise in selling small tools and it just might be possible to purchase the Taps and Dies for that thread form, or something that is so close as to make virtually no difference.
I remember once or twice repairing( by hard soldering) a broken end bolt and recutting the thread so I feel sure it is possible.

Geoff.

[Chris Ghent]

7 or 8 years ago I broke a bolt in my Jeffries G/D being heavyhanded with a screwdriver. I went to Richard Evans in a panic. But to a toolmaker of a certain age such things are relatively simple. Richard, who started work in a factory which made complete locomotives, has regularly made new non standard (as in, predating standard) bolts, and I watched him replace mine.

His technique is as follows...

Look at the bolt under a microscope and count the tpi (threads per inch).

Examine the profile of the thread.

Grind a tool to the same profile and check it matches under the microscope.

Make a new bolt.

Set the a thread cutting lathe to the same tpi.

Cut the thread.

[Chris Ghent]

Re-reading the OP I realise it is possible you wanted to clean up the threads on an existing bolt that might have been damaged. The only alternative to a die for this might be careful work with a thread file but it is tiny, rather you than me.

[Graham Collicutt]

I need to re-cut some threads for Wheatstone endbolts ( Aeola ). Anybody knows what exact thread they are and where to get a tap?

Some time ago I took the threaded plate, which is screwed to the bellows frame, out and then squeezed the plated on to the end bolt in a vice. Result good threads on 2 sides which gave me no further trouble for rest of time I had concertina ( G/D C Jeffries )

Graham ( advice warning trade Farmer )

[Chris Ghent]

Brilliant Graham, reminds me of the retired farmer called Geordie Sim, who lived across the road from me in the early 60s (I was in my teens) and who occasionally let me help him with his Wolseley 6/80 . One day he said to me, I'll show you the proper way to cross thread a nut. His careful process was extremely practical and made it possible to use a nut with the wrong thread, very handy 13,000 miles away from British tractor factories and a ready supply of spare parts.

Edited by Chris Ghent, 04 March 2012 - 07:45 AM.

[Geoff Wooff]

Brilliant Graham, reminds me of the retired farmer called Geordie Sim, who lived across the road from me in the early 60s (I was in my teens) and who occasionally let me help him with his Wolseley 6/80 . One day he said to me, I'll show you the proper way to cross thread a nut. His careful process was extremely practical and made it possible to use a nut with the wrong thread, very handy 13,000 miles away from British tractor factories and a ready supply of spare parts.

I had three Wolseley 6/80's once, to try to make one good car from the three... I was about half way through this task when an old friend suggested that I should not bother with the project because even when the 6/80's were new they were such bad cars that people used to set fire to them so as to collect the insurance money!

[Geoff Wooff]

Well,
I have measured my Wheatstone end bolt threads and I get the following results;

Sizes in Inches;

1898 bolt; diametre over threads 0.079" x 44 teeth per inch.

1916 bolt; 0.085" x 44 TPI.

1927 bolt; 0.083" x 44 TPI

1975 bolt (Dickenson) 0.084" x 44 TPI.

With the limited microscopic vision (of three pairs of reading glases stacked on my nose) and the short length of the threaded section of each bolt I estimated the 44 teeth per inch but it could be in the range of 43-45 tpi.

Unfortunately this thread does not relate to any standard size that I can find in books, charts, and on the web.
However it does suggest that Wheatstone had a standard and they stuck to it so at least we know that a Wheatstone bolt will fit, if the length is within a range that will fasten down the ends.

Geoff.