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DarrenSV650S
07-02-22, 08:47 PM
Anyone able to help me ID this bolt thread? It's from an American part.

I don't understand how their measuring system works :p

It nearly threads into an M4 nut then tightens up so it's very close.

https://i.imgur.com/eS5fzE5.jpg

https://i.imgur.com/Bio4i28.jpg
johnnyrod
07-02-22, 10:04 PM
Most likely Whitworth 5/32" 32tpi
GeorgeRYoung
08-02-22, 02:35 AM
I guess we're looking at different rulers. I get 5/16" dia. x 16 threads per inch.
redtrummy
08-02-22, 08:26 AM
5/16 x16tpi seems the American way and the thread pitch is different from metric.
Found this https://wooditfurniture.com/blogs/diy/m8-vs-5-16 but the article mentions M8?
garynortheast
08-02-22, 09:43 AM
That's 5/32 dia, 32 tpi. Count the graduations between the 1 and the 2 inch marks, there are 32 of them.
Bibio
08-02-22, 10:33 AM
yup 5/32 x 32tpi or #8 UNC
redtrummy
08-02-22, 01:06 PM
I am missing the plot here! In the first inch the scale is in 1/16ths, there are 16 thread peaks - Have I unwittingly been under a misapprehension for 55 years. Would someone explain in more detail. Thanks
Seeker
08-02-22, 02:22 PM
I am missing the plot here! In the first inch the scale is in 1/16ths, there are 16 thread peaks - Have I unwittingly been under a misapprehension for 55 years. Would someone explain in more detail. Thanks


The thread that is showing only just goes past the 1/2 inch mark, the small divisions are 1/32 not 1/16. The large "1" on the top of the rule is the 1 inch mark - I suspect you confused the 1/2 inch mark for the 1 inch mark.
GeorgeRYoung
08-02-22, 02:28 PM
. . . I get 5/16" dia. x 16 threads per inch.
Oops, I stand corrected.
redtrummy
08-02-22, 04:55 PM
The thread that is showing only just goes past the 1/2 inch mark, the small divisions are 1/32 not 1/16. The large "1" on the top of the rule is the 1 inch mark - I suspect you confused the 1/2 inch mark for the 1 inch mark.


Cripes senility fast approaches. Thank you Seeker as soon as I had another look it was so obvious. Mind you I had just drank a pint of beer that was pretty good - think I will have another one:smt026 and then take another look.
What a plonker I am
garynortheast
08-02-22, 05:50 PM
Cripes senility fast approaches. Thank you Seeker as soon as I had another look it was so obvious. Mind you I had just drank a pint of beer that was pretty good - think I will have another one:smt026 and then take another look.
What a plonker I am

That's ok, we always need someone to provide the cabaret entertainment for the evening! :smt046
DarrenSV650S
08-02-22, 06:02 PM
Glad it's not just me who finds it confusing :smt040

Thanks guys!