Yes they have , but the confusion is still there , I left out 'BSW' for this reason ( 1/2 BSW and 1/2 UNC are the only size under 1 inch that match , the rest have a different included pitch angle ) , or Japanese 'Metric' and German 'metric' as well ,,, ooops
All for the good old war machines of old ( and today ) , but we wont go there
.
The good old USA will stay staunch on their beloved SAE , yes TPI's of most might be the same as UNF , but thread angles differ , sometimes but only 1 degree ( included ) so yes it will start but after 2 or 3 turns bind ,,, that's where a quality 'Thread Gauge' is essential , you have to be so careful here as a wrong bolt can get really expensive real fast ( especially in stainless steel that binds and friction welds and that's IT !!! no chance of un-doing ) .
How do I know about the German/Japan metric system being different ???
, owning both a Takahashi and Zeiss at the same time , both as good as ( engineering wise ) as the FT focusers and the tools will fit ,,, but >>> threads
are the catch .
Thanks for your explanation Andrew by the way . There has been volumes printed on this subject but as I am only at 40 years of being a fitter /machinist/welder have seen this problem many a time as you seem to as well .
pss. , if it has this ,,, Made in the USA like this photo it will be SAE just like Asro physics , Feather Touch , and a few more , but NOT ! , like they say ' Designed in the USA ",,
,,,like many ( Japanese metric on a good day Chinglese metric made from plastic steel on a bad day ) ) , sorry to say sad but true
.
Brian.
Quote:
Originally Posted by AndrewJ
If they are US made, they will more likely be UNC/UNF.
( IIRC, SAE is effectively replaced by UNF for "general purpose" bolts like this )
The English ( and us ) use mainly true Whitworth thread for these smaller dia general purpose bolts, and in that case, Whitworth and UNC are "effectively" interchangeable for dia/pitch, but have a different thread angles.
As such, the test board at Bunnings should be able to confirm the thread pitch and dia.
If they are true UNC, then as noted above, they may have a different thread angle to whitworth, and the numbering system for anything less than 1/4" also changes to a "gauge" based nomenclature.
Ref https://en.wikipedia.org/wiki/Unified_Thread_Standard
ie Below 1/4" the UNC bolt dia is defined by a gauge, not a fractional dia ( like you would see on a Bunnings Blister pack )
So for UNC fasteners, we get 1/4-20, then 12-24, then 10-24, then 8-32.
vs say 1/4, 3/16, 1/8 etc
The specialist suppliers do stock these true UNC sizes, whereas Bunnings etc dont.
( CostLess Bolts in Moorabbin has pretty much all of these sizes in SS, and is where i get most of mine from )
Andrew |