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Thread of Cyclo Benelux shifter braze-on

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Thread of Cyclo Benelux shifter braze-on

Old 06-11-17, 07:57 PM
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Charles Wahl
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Thread of Cyclo Benelux shifter braze-on

Does anybody know what the thread spec is for the fixing screw of a 1940s-50s Cyclo Benelux shifter? As with many vintage shifters, these were provided for an adjustable band installation, and also there was a braze-on version.

I recently purchased a frame that has one of these braze-on fittings. I'll post more photos as soon as I've had time to take some, with description, but this one from the eBay auction will do for the time being.



A similar question was posed here by SailorBenjamin back in 2013; but it didn't result in a definitive answer.
https://www.bikeforums.net/classic-vi...threading.html

Since it's almost certainly a non-metric thread (i.e. not 5 mm x 0.8) I'm guessing that it's about a #10 or 3/16", but it might be 24, 26 or 32 tpi.

I have no intention of mounting/using a Benelux shifter. What I'd like to do is build the bike with a rear derailleur only (in the spirit of its original configuration), using a Simplex retrofriction. If I can substitute the fixing screw with a properly-threaded one, that would be OK. Otherwise, I'm thinking of removing the braze-on entirely. I'm planning to refinish the frame -- the paint is in good condition on much of the bike, but unfortunately there's corrosion on areas of the downtube, chain stays and seat tube extending from the BB, that needs to be taken care of, in order to preserve the frame.

EDIT: Cut to the chase: it has turned out to be an M5 x 1.0 screw, a coarser thread than the now-standard metric coarse M5 x 0.8 -- so it's "extra-coarse".

Last edited by Charles Wahl; 09-21-20 at 08:10 PM.
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Old 09-12-20, 07:43 AM
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I'm following up to my own post here. I did a bit more investigation, and found that the internal thread diameter of the above braze-on is about 3.8 mm; also, a #10-32 screw (4.6 mm major thread dimension) will not thread in at all (too large in diameter, by just a bit). By doing some reading on the UK Classic Lightweights site, I came up with this, in their Hints and Tips article #1:

"2BA bolts - Looking for replacement bolts for the drilled and threaded mudguard eyes found on most 50s frames? I had the threads checked and was told that they are 2BA which seems right and I have been able to get some from a local tool shop in polished zinc finish with cheese heads at about £1.50 for ten with nuts. The shortest I can get are 1” so some sawing is necessary. It seems that they had some brass ones until recently but the stock will not be replaced - they say they cannot get them. I guess many owners take the easy way to tap out and fit 5mm bolts."

Well, it turns out that this (to us, obscure) thread standard is also used most commonly on the threads holding the metal pointy part onto dart (pub game) shafts, and on British carburetors, but the reference to mudguard eyes (nowadays 5 mm x 0.8, which is also used for shifter screws) got me looking in that direction. I find on this site that the 2BA thread spec has an internal thread diameter that fits with my measurement:




Accordingly, I've found some stainless round-head slotted screws on BritishFasteners.com and ordered 4 of them -- at $5 a pop with postage and taxes. I will report back here when I've had a chance to try them out.

Yes, I could just retap the braze-ons to 5 x 0.8 mm, since I will never install Cyclo shifters, and probably nobody else will either. But I don't have a "bottoming tap" for that, and am loath to drill through the downtube just to retap. I have two different frames that have these braze-ons, so if I've found a workaround, that's good.

By the way, my original post above does not make the point that, while these braze-ons will take the square backing/stop plate for modern shifters (12 mm nominal square hole/boss) and they have a round boss exactly 9 mm in diameter that projects 6 mm exactly from the square, they do not have the "Campy-standard" flats ground onto part of the round boss. A shifter like the Simplex Retrofriction doesn't care about that, but others use the flats to key parts of the shifter that should not rotate in use.

And, in case you're wondering what I'm blathering about, here's a grainy image of the type of shifter that these braze-ons were intended to mount, along with the braze-on in question itself:


The braze-on is L.25A (1 shilling, 1 pence) and the friction screw is SP.58 (only 2 p!).

Last edited by Charles Wahl; 09-12-20 at 07:55 AM.
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Old 09-12-20, 08:06 AM
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Ah well done. Thanks for sharing your experience.

I ran into the same issue with a build of my 50's Sun Manxman.
......that project is sitting on the sidelines for now.
I tried several screws and had absolutely no success in finding a replacement.
Since the shifter, is friction I was contemplating running a Benelux shifter to a Campy Gran Sport rear derailleur since some BF user experience suggests that the
Cyclo Benelux derailleur can be a bit temperamental.
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Old 09-12-20, 08:48 AM
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I have just mounted a Simplex shifter on my Carlton Super Python frame and the threading was fine, and most of the frames from that period were meant to take either one or the other, as both Simplex and Cyclo products were popular.

That's a stunning R.O. Harrison frame. I've always admired the parchment background for that logo!

-Gregory
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Old 09-12-20, 09:39 AM
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Believe me, I have tried the screws from some Simplex retrofriction (both band-on and braze-on) shifters that I have, and they don't fit in this case.

R.O. Harrison frame (thank you); I consider myself quite fortunate to have it as a project, though a complicated one: while it was obviously well-used, the flamboyant paint is, on 85% of the frame, in remarkably good condition; however blue enamel has been daubed on in lots of places to cover rust spots or scratches at the base of the seat tube, on chain stays, seat stays and fork too. I've been looking for years to find an automotive finish that more or less matches, and decals that are good enough replacements (Lloyds' product sent to me by the successor to Nick is sub-par, IMO). I've seen BMWs and Minis that have something that might work. As for the decals,will need to design these myself, I think, which is a daunting documentation/graphics task.

The Harrison is box-lined, too, which is another challenge I am cogitating about: trying to think of a good "ruler" that will go around the tube circumference(s). Tape and a straightedge would work well enough for the longitudinal lines.

I have the same issues with a 1950s F.W. Evans frame: same braze-ons, horribly weathered (or sweated-on) paint on the top tube, though its graphics might be a bit easier to replicate.

The hat-trick of my English '50s frames collection is a JRJ (later Bob Jackson). I need to get working on these, and at least make them rideable, but other worldly tasks always seem to interfere.

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Old 09-12-20, 02:12 PM
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Well Charlie,
You just might be in luck here. Back in the mid 1970's I inherited a Benelux spare parts box. It was a cardboard thing with a bunch of parts in it. Not enough to build a derailleur, but a lot of bits and bobs. Nor a complete shift kit either, but I put all of those bits into a sandwich box that has graced to top of my tool box for close to 35 years. There are two super lever screws, and two 60 lever screws in the box. One right side shift lever, two conical shift washers, one tabbed shift backing plate but no frame stops.There is one of each side rear wheel clamping nuts and a few lock nuts for the axles. And a few odd Items I tossed in the box for myself like a steel chromed Campy pedal dust cap. If you promise to used these parts on a proper build, I will send then to you for cost of shipping and ask for pics of them in use.
Smiles MH It seems I have become a repository for obscure parts, these days.
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Old 09-12-20, 02:21 PM
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OTS,
I suppose I should give you a chance at some of these parts as well if you and Charlie can get an agreement on what should go to whom. Smiles, MH
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Old 09-12-20, 04:31 PM
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a less grainy image is found on page 3 of https://www.peterbrueggeman.com/cr/ca...x_sport_p2.pdf
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Old 09-12-20, 04:37 PM
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Originally Posted by Charles Wahl View Post
Believe me, I have tried the screws from some Simplex retrofriction (both band-on and braze-on) shifters that I have, and they don't fit in this case.
Oh, well I'm talking about the screws from one of the 1950s Simplex shifters that came with Juy 51 derailleurs and the like. Sorry to be confusing!

I happen to know that my Carlton frame was equipped with a first-generation Cyclo Benelux shifter right before I purchased it using the same mount, hence my confidence that back in the 1950s both companies actually used the same threading - at least based on that much evidence. Of course there's a chance one or even both screws on the shifters recently used with the frame was not original/correct, but I know for certain both were popular and also that the early Cyclo Benelux shifters were essentially copies of the successful Simplex components anyway, and attempting to take market share in England share away from Simplex was a major part of Cyclo business model in that era.

-Gregory



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Old 09-12-20, 04:46 PM
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Lots of good information in this thread.
Much appreciated.
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Old 09-12-20, 04:53 PM
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Well don't toss out the simplex parts as they will fit behind the Benelux just fine. The conical washers are different in logos and the threads are different but the rest will interchange. Smiles, MH
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Old 09-12-20, 05:00 PM
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Originally Posted by Mad Honk View Post
Well don't toss out the simplex parts as they will fit behind the Benelux just fine. The conical washers are different in logos and the threads are different but the rest will interchange. Smiles, MH
I'm pretty sure he wants to use the more modern Simplex Retrofriction shifter instead of the Benelux, and is wondering about the threading since the newer Simplex screw doesn't fit. If he wanted to use the Benelux lever with some other bits I think your solution would work just fine - squeeze together the parts that fit with whatever screw. The actual benefit gained by the Retrofriction shifter will require essentially the entire Simplex assembly to be mounted.
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Old 09-12-20, 10:13 PM
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Originally Posted by Mad Honk View Post
Well Charlie,
If you promise to used these parts on a proper build, I will send then to you for cost of shipping and ask for pics of them in use.
Smiles MH It seems I have become a repository for obscure parts, these days.
Thank you for the kind offer Mad Honk , but as I said in the 2nd post, I just ordered a few of the 2BA screws. Kilroy1988 is right that I want to mount a modern shifter, a Simplex Retrofriction, without modifying the braze-on if I can help it. So I'll see what happens when I get the screws. If that doesn't seem to be the answer, then maybe I'll get back in touch, so that I can determine what thread those darned things have!
In my research, I ran across the Wikipedia article ( https://en.wikipedia.org/wiki/Britis..._screw_threads ) that claims that the British Association thread standard was developed to be a metric-based one, in the 1880s. Strangely, the base size (0BA) started with a 6mm x 1.0, and then successive specs happen to be 0.9 x the previous. Pretty weird, compared to what we know today as the metric thread system where whole and half mm measurements are used.
BTW: I'm only "Charlie" to my spouse and others I have known for at least 30 years -- a personal/private rule.
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Old 09-12-20, 11:18 PM
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I hope the $5 screws you purchased work out. If not, I would expect BSC 3/16-26 is a strong possibility. BSC (aka CEI) threads are not uncommon on vintage British cycles (pedal or motor).
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Old 09-12-20, 11:47 PM
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Yes, I could just retap the braze-ons to 5 x 0.8 mm, since I will never install Cyclo shifters, and probably nobody else will either. But I don't have a "bottoming tap" for that, and am loath to drill through the downtube just to retap....
...these small 5 x 0.8 taps are cheaply and readily available at places like Home Depot (at least my HD), and on Amazon.
It's not a big deal to buy an extra one and use a grinder to take down the tapered end. ( Actually, they are so hardened and brittle that it's often not hard to just snap off the tapered end.)

What you get as a result is a passable bottoming tap. You start the re-thread with a plug tap (slight taper), and when you run out of room you switch to the modified one.

In case all your workarounds end up going astray, this is probably a better alternative than removing the braze on. (I think....maybe not.)
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Old 09-13-20, 02:23 AM
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Originally Posted by Charles Wahl View Post
Since it's almost certainly a non-metric thread (i.e. not 5 mm x 0.8)
I did not read the whole thread. May be following informations are unsuitable:

Originally Posted by HeikoS69 View Post
You're right!
France used their own standards for threads. "Systeme Internationale". In 1959 the standards were harmonized to ISO, manufacturers worked with the old standards throughout the 60s.
They were metric yes. The pitch was different to ISO for small diameters: M5 => 0.9mm i.o. 0.8mm, M5.5 also had 0.9mm pitch
If you google for images "Filetage SI" site:fr
you will find some tables with data (Pas = pitch)
Tools for making M5 x 0.9 threads are available, thumbscrews not.
Originally Posted by HeikoS69 View Post
A little history of metric thread standards (cited from Screw thread standards for federal services 1957, National Bureau of Standards H28, 1957):
( Slightly of topic)
"Metric-thread systems have been used in European Continental countries since 1848, particularly in France, Germany, and Switzerland. Efforts toward international unification of these systems led in 1898 to a conference in Zurich, Switzerland, which was attended by representatives from engineering societies and other technical organizations in France, Germany, Italy, the Netherlands, and Switzerland. Organizations in other countries such as the United States and Great Britain, were also invited but did not send delegates.
The Zurich Conference of 1898 adopted a system of metric threads which was practically the same as that previously developed in France by the Société d'Encouragement pour l'Industrie Nationale in 1894. This system became known as the "International System" and is usually designated as the SI System" (from the French name, "Système Internationale"). This system was recommended for adoption by all countries where metric threads were used and covered a range of nominal diameters from 6 to 80 mm, inclusive, with associated (coarse) pitches. The threads were intended for use as fastening threads in machine construction and hence for application to the general types of screws, bolts, and nuts.
The need for metric coarse threads in sizes smaller than 6 mm and Iarger than 80 mm, and of metric fine threads, led a number of Continental European countries to extend the original SI series. However, these additional series showed differences in respect to nominal diameters, pitches, and diameter-pitch combinations. Nationai standardizing bodies, organized in Europe during and after the first World War, made an effort to bring some order in these additional series. In 1926 the International Standards Association (ISA) was founded and one of its first technical committees dealt with metric threads. At a conference held in Copenhagen in 1931, this committee succeeded in getting agreement in principle on five recommended series of metric threads, designated by the letters A to E. It took several more years to put the final touches on this unification plan, and ISA Bulletin 26, in which the recommended ISA series are listed, was not published until September, 1940. The original series of SI coarse threads was extended to diameters as large as 600 mm (about 24 in.), the pitch being 6 mm for all sizes above 80 mm. Therefore, the term "coarse" threads was avoided and the original SI series, with its upward downward extensions, was designated as "ISA Series A." However, ISA Bulletin 26 and the national standards set up in accordance with it, explicitly refer to the ISA Series B to E, inclusive, as "fine threads." The ISA became inactive in 1942 as a result of the second world war. Following the war the International Organization for Standardization (ISO) was established, and ISO/TC1, Screw Threads, held its first meeting at Paris in 1949. This technical committee subsequently developed recommendations for basic and design thread profiles, and standard series for metric and inch screw threads."

The French National Standard metric threads below 6 mm diameter always were called "S.I.", though they were not covered by those standards and differed from the later 1940 ISA Series A (0.8 mm pitch for 5 mm, 0.9 mm pitch for 5.5 mm). In Germany the standards (from 1918) were called "DIN" which means "German Industry Standards".
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Old 09-13-20, 09:13 PM
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Originally Posted by HeikoS69 View Post
I did not read the whole thread. May be following informations are unsuitable:
Well, I have read the whole thread, as tedious as that may be -- maybe that's an advantage or a disadvantage, I dunno. Anyway, thank you for the disquisition on metric standards, but my money is still on 2BA, the dart-head threading.

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Old 09-13-20, 09:37 PM
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Oops. Edited my above post. Not what I meant to say.
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Old 09-13-20, 09:49 PM
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I'm betting it's 3/16-26 British cycle thread, but it seems sizes smaller than 5/16 are unobtainium. This supplier suggests 2BA or 3/16 UNF as a close substitute.
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Old 09-14-20, 01:32 AM
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Originally Posted by Insidious C. View Post
I'm betting it's 3/16-26 British cycle thread, but it seems sizes smaller than 5/16 are unobtainium. This supplier suggests 2BA or 3/16 UNF as a close substitute.
Did you mean 3/16-32? I can't find a thread standard for 3/16-26, which would be very coarse for such a small screw, and I've already tried 3/16 UNF, which is 32 TPI, and was clearly too large. I seriously doubt that it would be a 3/16-nominal thread, on that basis -- but we'll see soon enough. The 2BA spec has a major external thread diameter (see above) such that the halfway point between max. and min. is 0.174" (though expressed/specified in mm), significantly smaller than 3/16". All I know, having only a minor diameter of internal thread to work with now (3.8 mm), which is smaller than the 3/16-32 tap drill size of #23 , or 3.97 mm. My source for that is here.



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Old 09-14-20, 02:33 AM
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I meant 3/16-26, which apparently does not exist. I incorrectly thought that all sizes of BSC/CEI were 26 TPI (which the larger sizes all are).

I just noticed the BA threads have a 47.5 degree thread form vs. 60 degrees for CEI. That is a big enough difference to visually discern- if it was the male thread you had in hand. I am curious to know how the BA screws fit when they arrive.
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Old 09-17-20, 12:25 PM
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Well, I received the 2BA screws yesterday, and they're no-go, just like the #10-32 screws I've also tried -- they'll both look like they'll go in, but they stop after about 3/4 turn. Because it seemed to me, on closer inspection, that the internal thread pitch of the braze-ons is larger than that of the screws, I sanded down a bamboo chopstick so it was just a bit larger than the major diameter of the screw, and force-threaded it into the braze-on. Imagine my surprise when I found that the internal thread has about a 1 mm pitch! I can't seem to find any sort of screw having that major diameter (about 4.7) and that coarse a pitch, unless it's a UNC 10-24, or a Whitworth BSW (coarse) 3/16-24, but I'm not inclined to believe, unless the bamboo stick slipped under threading (doesn't look like it), that the threads could be 24 TPI. Still, I will find a 10-24 screw and see if that fits any better.

The British Cycling standard (BSC or CEI) is a good guess, but I can't find any evidence that 3/16-26 was ever "a thing", which would be the only "fit" for this thread.

The bad news is that rethreading to the standard used by Campagnolo-style braze-ons (5 x 0.8 mm) probably won't work, since the thread pitch of the Cyclo is not close enough, and the 5 mm (nominal, most that I've measured are actually smaller) screw diameter is too close for any thread without a similar pitch. The only "retap" that I can see working is 6 x 1.0 mm, which would mean drilling out any shifter I wanted to use on it.
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Old 09-17-20, 07:33 PM
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This is the bolt from a plastic Simplex shifter off an early 70s UO-8.

It is M5x1.0mm.

The pitch is an exact match for the M6x1.0 tap in the first photo. The diameter is 0.191in ~= 4.85mm.




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Old 09-17-20, 07:45 PM
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If you want I can drop it in the mail for you along with the matching plastic wingnut. Let me know.
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Old 09-17-20, 08:34 PM
  #25  
Insidious C. 
Crash Test Dummy
 
Join Date: Jan 2014
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Bikes: Dawes, Williams, Raleigh, Daccordi, Scott, Univega, Mercier, Vitus, J. Anquetil, Specialized

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For grins I measured this thumbsrew from a Resilion DT shifter. From measurements it looks to be 3/16-32. I wouldn't be surprised if Cyclo Gear used the same screw thread, as both are British and similar vintage.

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