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Bolt identification? NOT VW

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donn Wolfsburg Elder

3,515 posts · joined Nov 2005 ·

#994904
I'm trying to identify a bolt size / thread, not out of a VW and unlikely to be metric as it's to fit a tread in an old machine manufactured in Scotland, I have a bolt that fits reasonably well and have measured the pitch with a screw pitch gauge ..(28) and the OD of the thread is 5.4 mm, pretty sure that's exact OR .2126 inches (by my conversion calcs.) Using some identification charts I found (Google is my friend) the nearest I can come up with (though not exact) is an American (?) UNF, although it's unlikely I would think as it's an English or at least Scottish machine, I have a 1/4 Whitworth die (at least it has 1/4 W20 stamped on the body of the die) and that wont fit, too tight and an NF28 die and that's no good either, too loose.
Does anybody out there in help-full land have a clue to help.
The only place I can see where I may be off track is that while the bolt I have, I don't have a nut to fit, does run into the threaded part all the way to the bottom (15 mm) I can't be sure that it is a really good fit, feels OK but I'm not positive
Thanks in advance
Don
I dream of a day when a chicken can cross a road without being asked for it's motive!

mackaymanx Custom Title Time!

1,611 posts · joined Jan 2006 ·

#994906
I would suggest B.S.F British Standard Fine but the pitch would need to be 26 tpi for that O.D.

edit rechecked my tables and it could be 7/32 B.S.F which is 28 tpi with an od of 5.55mm
Quote of the week
"Do I wish to send them to you again, nope, no interest can't be bothered really, to much hassle for little or no return."

[IMG]https://www.vw-mplate.com/mplate2-18600.png[/IMG]

HappyDaze Superannuated

2,887 posts · joined Jun 2009 ·

#994908
Have a look here, donn :-

http://www.tracytools.com/taps-and-dies

I had a similar problem with my Minerva. There was a thread I had not heard of called UNS.....1/4 UNF is 28 TPI, 1/4 UNC is 20 tpi - 1/4 UNS is 24 TPI !

If you need 1/4 UNS taps & die, you can borrow mine. Good luck.👍
I'd rather wear a Beetle out by racing it than by polishing it!

psimitar Son of Jim - Creator of Good

2,506 posts · joined Jan 2009 ·

#994919
HappyDaze wrote:Have a look here, donn :-

http://www.tracytools.com/taps-and-dies

I had a similar problem with my Minerva. There was a thread I had not heard of called UNS.....1/4 UNF is 28 TPI, 1/4 UNC is 20 tpi - 1/4 UNS is 24 TPI !

If you need 1/4 UNS taps & die, you can borrow mine. Good luck.👍
Just out of interest. I know the F=fine and the C=coarse for UN sizes but any idea what the S stands for?
madness is in the eye of the beholder 👍

HappyDaze Superannuated

2,887 posts · joined Jun 2009 ·

#994922
"Special", I think.....it was a new one for me.

I think Harley Davidson used UNS threads.
I'd rather wear a Beetle out by racing it than by polishing it!

donn Wolfsburg Elder

3,515 posts · joined Nov 2005 ·

#994929
Ok, thanks for that fellas, I'll head off to the bolt suppliers armed with that info on Monday, Saturday just before closing I took a punt but came home with the wrong gear. 😠
I dream of a day when a chicken can cross a road without being asked for it's motive!

HappyDaze Superannuated

2,887 posts · joined Jun 2009 ·

#994930
7/32 BSF looks like it.......however [just to confuse the issue], there is a metric 5.5x0.9 thread which is VERY close.🙄

BSF thread angle is 55 degrees, Metric is 60 degrees. 🤪
I'd rather wear a Beetle out by racing it than by polishing it!

donn Wolfsburg Elder

3,515 posts · joined Nov 2005 ·

#994991
We'll the good news is that it sure looks like 7/32 BSF, the bad news that it's no longer made or not available, depending on who you ask, so I've got the job of drilling and tapping a new thread.
Thanks for the help 👍
I dream of a day when a chicken can cross a road without being asked for it's motive!

modnrod Fahrvergnugen

978 posts · joined Mar 2011 ·

#994995
Hhmmmm.
I had our local WA bolt and fastener companies all tell me I couldn't get metric fine M18 (common in Euro). They also told me that you could no longer get SAE 10/32 or 8/32 (I use them here at work on old NASA shite).
What that translates too is they either haven't even heard of them and are too bloody lazy to look, or they haven't got suppliers who stock them.

I found them on Ebay no worries.

donn Wolfsburg Elder

3,515 posts · joined Nov 2005 ·

#995001
Well Modnrod, I'm not even going to look, I've already tapped the new thread and I don't want to find out that I didn't look hard enough. 🙄😂
I dream of a day when a chicken can cross a road without being asked for it's motive!

1500S Custom Title Time!

1,418 posts · joined Mar 2005 ·

#995222
modnrod wrote:Hhmmmm.
I had our local WA bolt and fastener companies all tell me I couldn't get metric fine M18 (common in Euro). They also told me that you could no longer get SAE 10/32 or 8/32 (I use them here at work on old NASA shite).
What that translates too is they either haven't even heard of them and are too bloody lazy to look, or they haven't got suppliers who stock them.

I found them on Ebay no worries.
Maybe we shouldn't use the term S.A.E as it confuses those who don't know that it is replaced by Unified National Fine and has been for a long time. If the counter jockey looked up the SAE chart and couldn't find a #8-32 thread on it he was correct as it is a UNC thread................... but we all know that!

A good reference is http://mdmetric.com/tech/tict.htm as it has all the common threads we need to know, old and new. The old DIN (the Japs used them for their old JIS as well) is useful to know as well for old machinery from Japan and Europe. Some pitches and diameters differ in the small sizes.

modnrod Fahrvergnugen

978 posts · joined Mar 2011 ·

#995228
donn wrote:Well Modnrod, I'm not even going to look, I've already tapped the new thread and I don't want to find out that I didn't look hard enough. 🙄😂
Jobs done then! 😂

Yellowbug65 Casual Dubber

49 posts · joined Feb 2014 ·

#995253
For future reference a copy of machinerys handbook has every thread ever produced and you can pick up a copy off amazon fairly cheap , you don't need the latest so an older version is fairly cheap and it has a lot more useful information than just thread types
Cheers