End Bolt 43tpi die

[4to5to6]

I found Geoff’s post:

 

 

On 3/6/2012 at 12:43 AM, Geoff Wooff said:

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.

 

Interesting stuff.

[Don Taylor]

Heretical suggestion, but would it not be easier to simply replace the little plates that the end bolts screw into with new ones that have been tapped to fit bolts that are currently available?

[Stephen Chambers]

On 9/11/2024 at 3:59 PM, Don Taylor said:

Heretical suggestion, but would it not be easier to simply replace the little plates that the end bolts screw into with new ones that have been tapped to fit bolts that are currently available?

 

It's certainly what I do with cheap models of concertina, especially when the bolts are very rust-prone mild-steel ones with cheese heads, or woodscrews.

 

Years ago it used to be 7BA that I'd use (and I think Crabb's had gone over to using them on their new instruments, if I remember rightly), but then the odd-numbered BA threads were done away with and only even-numbered ones are available now. So more-recently I went Metric and started using M2.5 x 30mm, first (a bag of 500!) in stainless steel, and this year I managed to get some in brass as well.

 

But, never mind the thread for a minute, the heads on the bolts have never been (flat-topped) cheese head on better models of concertina, they've always had "fillister head" ones (with a domed crown), and they can only be got (with difficulty), in stainless steel, in the United States, where the equivalent (Whitworth-related) thread is 3-48.

 

But, in this particular case (a bass), extra-long 2" bolts are needed, and you won't find ready-made ones that are as thin - in fact 1 1/4" (for normal concertinas) are hard enough to find as it is!

 

 

 

Edited September 12 by Stephen Chambers
Edited to add "or woodscrews"

[Tiposx]

Spot on. If I can’t find good old bolts then I convert to 8BA. If the existing bolt holes are wide enough then I convert to M2.5. Ideally I convert a whole end, ( 6 in my world) but it depends on what the owner wants.

I have turned bolts from solid round bar, but now I prefer to use brass wire, with new heads silver soldered on. I have also replaced worn out heads with new ones where possible.

I only use brass.

[Stephen Chambers]

2 hours ago, Tiposx said:

Ideally I convert a whole end, ( 6 in my world)

 

I'd always change all 12 while I'm at it, it's no big deal and much less confusing (and asking for trouble) to have more than one thread on one instrument.

[4to5to6]

A source for new bolts would be appreciated.  Preferable a North American source but anywhere is fine.

 

C. 1900 bass - 0.0855, 44tpi, 2.218“

1926 Amboyna TT - 0.0850 5BA, 1.240”

1927 ME TT - 0.0860 5BA, 1.162“

 

Thanks.

[adrian brown]

On 9/11/2024 at 7:27 AM, alex_holden said:

As I understand it the BA standard was based on the Swiss Thury standard, which was in turn based on a study of various non-standardised threads in use at the time by Swiss watch makers. Louis Lachenal was a Swiss watch maker before he came to England. An important feature of this family of thread forms is the rounded crest and root, which reduces stress risers.

 

I think it is fair to describe the 'concertina thread' as having a form like BA, approximately the same major diameter as 8BA, and approximately the same pitch as 5BA. That doesn't mean it is a BA thread. A complicating factor is that there are slight differences between the various manufacturers which make them incompatible with each other. e.g. a die for Jeffries end bolts probably won't make bolts suitable for Wheatstone nut plates.

 

A few years ago I tried to commission a specialist firm to make a tap and die set to replicate Wheatstone threads. They were quite difficult to deal with and quoted me an astonishing price (I suspect they simply didn't want to take the job). I also briefly experimented with making my own tap but was much less successful than Adrian.

 

@4to5to6: you don't need/want an acetylene torch to harden tool steel. A propane torch and a few fire bricks arranged around the part gets plenty hot enough for hardening. You want to heat it gently and sustain the temperature for a while so it has time for the molecules to rearrange all the way through, but don't overheat it because that causes large crystals to form. You can temper it either with a low flame and watching the colours, or you can do it in a conventional kitchen oven if you trust the thermostat (I've also used a deep fat fryer!). I also have a proper temperature-controlled electric heat-treating oven but rarely use it because it's a bit of a faff to set up and takes a while to get up to temperature.

 

Actually Alex, I only got the idea to make my own end bolts after being inspired by your post in 2017:

In particular, I wanted to try the hollow cutter that Theo mentioned and said was an idea that came from the Crabb workshop. (It works brilliantly!) From there, things got a bit out of hand and I spent several days tinkering away at them.

 

What part of the die making process went wrong for you? I'd be happy to share my experience, but I fear I might have just had a lot of luck to get it to work so well first time! As I said, I was terrified the tap would snap when I was cutting the thread in a piece of 1/8" gauge plate, but luckily, it held...

 

Anyway, a belated thanks to you for the idea 🙂

 

Adrian

 

 

[alex_holden]

19 minutes ago, adrian brown said:

Actually Alex, I only got the idea to make my own end bolts after being inspired by your post in 2017:

 

I'd forgotten about that post. Last year I turned a set in stainless steel, which was much harder to work with than free-turning brass (my client wanted silver-coloured traditional slotted heads, but didn't want nickel due to an allergy). Coincidentally I will need to turn up a fresh batch of brass bolts soon. Maybe I will try making one of Theo's hollow cutters first.

 

35 minutes ago, adrian brown said:

What part of the die making process went wrong for you? I'd be happy to share my experience, but I fear I might have just had a lot of luck to get it to work so well first time! As I said, I was terrified the tap would snap when I was cutting the thread in a piece of 1/8" gauge plate, but luckily, it held...

 

I ran into several problems making the tap, mainly due to limitations of my lathe, and after some unsuccessful attempts I put the idea on the back burner thinking I might try again if I ever upgrade to a better lathe. To be honest I'm happy enough with 8BA, and you can still buy taps and dies for it. The closest metric thread is M2.2x0.45. The only reason you might want to use the traditional 'concertina thread' on a new instrument is that it is a very coarse pitch so you don't need to turn the screwdriver as many times to remove the ends.

[Tiposx]

I concur with Adrian in that it was Alex's old post that inspired me to make my own bolts. I learned from the last post that M2.2 coarse standard existed. This is most useful, thanks again Alex.

 

[Stephen Chambers]

11 hours ago, 4to5to6 said:

A source for new bolts would be appreciated.  Preferable a North American source but anywhere is fine.

 

Concertina Connection in the United States offer a custom end-bolt making service: https://www.concertinaconnection.com/end_bolts.htm

 

                                  Concertina Connection Inc.
                                  9811 South Big Rock Lane 
                                  P.O.Box 211
                                  Valleyford, WA 99036
                                  USA

                                                      

                               phone: 509-922-1626
                                     fax: 509-922-1626
                                 email: info@concertinaconnection.com

[adrian brown]

5 hours ago, alex_holden said:

 

I'd forgotten about that post. Last year I turned a set in stainless steel, which was much harder to work with than free-turning brass (my client wanted silver-coloured traditional slotted heads, but didn't want nickel due to an allergy). Coincidentally I will need to turn up a fresh batch of brass bolts soon. Maybe I will try making one of Theo's hollow cutters first.

 

Theo probably has more experience with those hollow cutters than me, but I found I needed to back bore the cutter to a larger diameter to provide some clearance to the shaft you've just cut. I think only about 3mm of the bore is at the finished diameter, the rest is about 0.25mm larger to stop the shaft from simply snapping off due to the friction. I hope this might save you a bit of time 🙂

 

5 hours ago, alex_holden said:

 

I ran into several problems making the tap, mainly due to limitations of my lathe, and after some unsuccessful attempts I put the idea on the back burner thinking I might try again if I ever upgrade to a better lathe. To be honest I'm happy enough with 8BA, and you can still buy taps and dies for it. The closest metric thread is M2.2x0.45. The only reason you might want to use the traditional 'concertina thread' on a new instrument is that it is a very coarse pitch so you don't need to turn the screwdriver as many times to remove the ends.

 

Yes, you're right about the coarse thread - modern instruments seem to need ages to get all the screws undone, in comparison to old ones! And perhaps having a non-V profile gives the old screws a bit more resistance to stripping?

 

Adrian

 

 

[Tiposx]

Back to 4to5to6 original posting. You could ask Steve Dickinson? He has helped me out in the past with the correct woodscrews for an old Wheatstone.

[4to5to6]

I have yet to find a source for 3-48 bolts and M2.5 x 30, etc. bolts over 1” (25mm) preferably in North America as alternate end bolts.

 

Cheese,  fillister or binder head with a slot drive preferred.  I am open to Whitworth and BA as well even in a finer thread than 43tpi.  

 

Custom made bolts are very expensive so would then have to make my own if not available.  It would be awesome to get these off the shelf to save time and money.

 

On this topic…

 

I also have a need for the small 3/8” screws that hold rolled metal end plates on from the inside.  I’ll attach a photo.

 

And of course the long thin English thumb strap and pinky rest screws… these also are also impossible to find new.

 

Does anyone know of a source for brand new bolts and screws like these?

 

 

Edited September 12 by 4to5to6

[Clive Thorne]

Making your own bolts seems (to me) to be a lot of effort for very little (if any) tangible gain. If it were me I would convert everything to M2.5, probably stainless steel, even if it meant going to allen heads or cheese heads.

 

As for the screws in the above above spost, should be easy enough to get from a serious ironmonger, or on line.

[4to5to6]

I just found these:

 

Uxcell M2.5 X 40mm 304 Stainless Steel Crosshead Phillips Round Head Screws Bolt - 60pcs - $10.91 USD

 

https://www.harfington.com/products/p-1102106

 

Is 60mm long possible? Almost there 😊 

 

Reference:

C. 1900 hex bass - 0.0855, 44tpi, 2.218“ (56.4mm)

 

1926 Amboyna TT Aeola - 0.0850 5BA thread, 1.240” (31.5mm)

 

1927 ME TT Aeola - 0.0860 5BA thread, 1.162“ (29.5mm)

.

Edited September 12 by 4to5to6

[RogerT]

16 hours ago, Clive Thorne said:

Making your own bolts seems (to me) to be a lot of effort for very little (if any) tangible gain. If it were me I would convert everything to M2.5, probably stainless steel, even if it meant going to allen heads or cheese heads.

 

As for the screws in the above above spost, should be easy enough to get from a serious ironmonger, or on line.

Yes, this has been my approach. It's also possible to get m2.5 bolt/wood inserts.

Edited September 13 by RogerT

[Stephen Chambers]

3 hours ago, RogerT said:

It's also possible to get m2.5 bolt/wood inserts.

 

I'd use the screw-in inserts as necessary, but I'd usually re-tap the existing receivers to M2.5, or 3-48, depending on which I find more expedient.

Edited September 13 by Stephen Chambers

[Don Taylor]

5 hours ago, RogerT said:

even if it meant going to allen heads or cheese heads.

Slotted head screws, like cheese heads or fillister heads, are the work of the devil!

 

How many concertina ends have been gouged when a slotted screwdriver slips when removing the screw? 

 

A better question might be, how many have not been gouged over the course of a lifetime.

Edited September 13 by Don Taylor
typo