Youdelr

I broke the thumb screw on my VAR third hand and I am having difficulty identifying the 5mm thread pitch and a source to purchase. It appears finer than .8 but does not match a pitch on my gauge

francophile 

Being VAR, I'd assume metric, but may not be true if it's a newer piece.

Usually what I do in this case (assuming my bucket 'o bolts has nothing) is go to my local Ace Hardware and hit the wall of hardware bins to find something that fits and jot down the details on the pitch. Then go to Amazon.com and order a thumb screw with the same.

Had to do that with a Park FT-4 recently. Managed to get a back of replacement winged fasteners that work perfectly on the sliding apparatus.

JohnDThompson 

My VAR #2 3rd hand tool uses standard 6mm x 1mm thread for the thumbscrew. My is relatively new (from the early 80s) and has a knurled, black-oxide thumbscrew. Older versions of the tool used a brass wingnut. I don't know if those might be a different thread spec.

clubman 

And I have the same problem. Nothing I have will fit so let's let each other know when we find it!

JohnDThompson 

If your tool has a 5mm bolt (mine, purchased new in the early 80s, has M6 thread), you may be able to re-tap it to take an M6 bolt instead of whatever the original was.

scarlson 

HA, my VAR pin tool pins are something weird too, but they're coarser than 0.8 and might be bigger than 5mm but smaller than 6mm! Still figuring out what in the world they are.

T-Mar

I just checked mine with my thread dies. It's also M6 x 1.0. Black oxide finish with cross-hatch knurl per JDT's description.

madpogue 

In order to save, what, a dollar or two? Yeah, I've done the retail visit -> order online trick on items where I might save a significant chunk of money online. But a single thumbscrew like this will cost at most $2-3 retail. Hardly worth going back to order it, and having to wait for it, and wonder about the quality.

In my particular case, for something of that scale, I'm happy to patronize my local Ace. It's the definition of a neighborhood hardware store. Been around for close to 100 years, 75,000 items crammed into a space two neighborhood-style storefronts wide, aisles way too narrow for ADA, creaky uneven wood floor. Guys (not all guys) working there who acutally know where things are, and know what you might need. The old black dog sleeping at the end of the counter died a few years ago. I'm happy to spend money there now and then, just to help keep them viable. Bonus -- they participate in Bicycle Benefits, 5% discount on just about anything I buy there. That often makes their prices competitive with (and sometimes better than) online.

Another on-topic case in point - Testors paints for frame touch-up. The local ACE has a modest selection, but they can get anything you want. If we find a color we _think_ is a match for a particular job, and order online, and it's doesn't look right when it gets here, returning it is a PITA. If we order through ACE, stop by the store when it arrives, and we decide it's not a go, it's just a no-sale.

Ooops, way TMI. Short version - just match it up at the local hardware.

francophile 

Before going off on rants, I always try to understand why someone is giving the suggestion, and asking a couple of simple questions normally goes a long way towards that.

Two answers I would've given to help you understand why I said what I said, as someone with a close friend who co-owns the two Ace stores closest to me and goes out of his way to buy everything there for decades:

1) You should know, Ace hardware doesn't own the hardware bins. It's owned and managed by a 3rd party that services and refills it. According to my buddy, It's a loss-leader for them when you factor in floor space used, staff help required, etc.

2) The 3rd party managing the hardware bins doesn't carry thumbscrews, nor the winged screws I needed, so I and the OP would still need to purchase the item elsewhere, but going with the knowledge of exact threads required.

I've been shopping at Ace (and the occasional Scotty's before it went tits-up) because smaller hardware stores always have more knowledgeable staff and far better service than big-blue and big-orange stores. I'll continue supporting them as I always have.

obrentharris 

Mine also has the brass screw. The thread pitch matches up with my 28tpi gauge very nicely. Diameter appears to be 5mm. 5mmx28tpi? Crazy, yes?
But I found this French site which sells a 5mm x 28tpi tap.
But good luck finding a thumbscrew in this size!
The suggestion to tap it out to 6mm is perhaps your best bet. Looks like there is plenty of material to accommodate the larger hole.
Brent

madpogue 

Good advice, and fortunately there are no rants in this thread (except, perhaps, in the eye of the beholder....).

repechage

We need Milo to chime in, I have a number of times encountered French made parts, tools, where the screw was "metric" but not the common thread form or pitch that is the typical today.
Did seem reasonable but atypical.

JohnDThompson 

I have a VAR #13 pin spanner with a brass wingnut threaded 5mm x 1.0mm; perhaps that's the same as the old-style #2 3rd hand tool?

obrentharris 

Here is thumbscrew from my VAR 3rd hand. It is between 1.00mm and .80mm. The OP seems to state that his is the same.



Brent

obrentharris 

Mine mates up very nicely, however, with a 28tpi gauge.



Brent

scarlson 

Therefore probably 0.9. 1/28 * 25.4 = 0.907

I don't think a French company would use any thread pitch defined in inches (Metric home-field pride is definitely a thing), and m5x0.9 is also definitely a thing.

But be careful of the diameter! m5.5 is also a thing.

HeikoS69

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.

madpogue 

^^^^^ Gotta love how they had the gall (or Gaul?) to call their own standard, which no one else used and which eventually (present "company" excepted) disappeared, "Internationale".

Then again, we in the US have the "World Series" (which, yes, was called that long before the Toronto and Montreal expansion teams existed).

[Dangit, the left parenthesis key on my keyboard just wore out....]

HeikoS69

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".

CAK 

Looks like the same screw for my VAR truing stand

Mel Pinto imports had everything and I think there is a guy in Maryland or Washington that has some of his old stock.

Charlie @ Kopp’s