bolt nut and washer sizes ?

stryder

stryder

stryder

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greater manchester
hi
i know this is a strange thing to ask about on the forum but does anyone know for sure how bolt,nuts and washer sizes are worked out? eg.M6,M12,M16.etc
does it go by the diameter of the bolt shaft or the size of the head or the length of the bolt? and will an M12 nut and washer fit an M12 bolt?
i know this probably a daft question but its one of those things you either know or you don,t:confused:
 
I'm pretty sure M12 screw is diameter of shaft. M12 nut is inner diameter of nut and M12 washer is M12 clearance hole for inner diameter.

So they should all go together nicely. A quick check down B&Q would confirm.
 
barf0r said:
I'm pretty sure M12 screw is diameter of shaft. M12 nut is inner diameter of nut and M12 washer is M12 clearance hole for inner diameter.

So they should all go together nicely. A quick check down B&Q would confirm.
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you would think so but a couple of weeks ago i went in there for some wing nuts , bolts and washers and they didn`t ! i was in there for about half an hour while the guy opened different packs and tried to match them up cos the ones that were supposed to fit according to the size printed on the pack didn`t.
 
stryder said:
you would think so but a couple of weeks ago i went in there for some wing nuts , bolts and washers and they didn`t ! i was in there for about half an hour while the guy opened different packs and tried to match them up cos the ones that were supposed to fit according to the size printed on the pack didn`t.
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maybe a different thread ?
 
IIRC the M part indicates it's metric, there are also Imperial ones and some with an unusual thread (from memory electrical screws for example are a ******* size/thread on purpose something like M3.5).

Depending on what the screw/nut/bolt was from and how old it is can all affect the thread, not to mention some just have bad tolerances or are plain old junk (Homebase screws tend to be absolutely rubbish*).

What's the bolt from?



*I swear they use the cheapest possible pig iron for them, half the time the longer ones are bent in the pack, or the shorter ones break whilst being done up - the rest of the time their heads get chewed up no matter how careful you are (not due to the wrong bit, just the metal on them being too soft).
 
Metric threads are the diameter of the screw. An M12 is actually roughly 11.6-12mm. However, there is different pitches of threads. M12 standard is M12x1.75mm pitch (Distance between points). Fine is M12x1.
There are loads of different standards. Depending on the use. Such as BSP for pipes (Where the size is actually the bore of the pipe, not the thread size - just to confuse matters).

http://en.wikipedia.org/wiki/ISO_metric_screw_thread

An engineers pocket guide is the Zeus Book. Contains many thread sizes for handy reference. Completely overkill for home use.
Its my job.
 
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Dano said:
Arrr, that be whitworth.

(Darn old fashioned threads on modern equipment)
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Nothing wrong with old fashioned threads and things...it's why you never ever throw out a tool that isn't broken, and if it is broken you try to find another use for it ;) (my dad's got some tools in the garage that go back to the 40's or earlier).
 
Werewolf said:
Nothing wrong with old fashioned threads and things...it's why you never ever throw out a tool that isn't broken, and if it is broken you try to find another use for it ;) (my dad's got some tools in the garage that go back to the 40's or earlier).
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Oh there is when you've just sheared a whitworth threaded screw off and nowhere in town sells the things.
 
Werewolf said:
IIRC the M part indicates it's metric, there are also Imperial ones and some with an unusual thread (from memory electrical screws for example are a ******* size/thread on purpose something like M3.5).

Depending on what the screw/nut/bolt was from and how old it is can all affect the thread, not to mention some just have bad tolerances or are plain old junk (Homebase screws tend to be absolutely rubbish*).

What's the bolt from?



*I swear they use the cheapest possible pig iron for them, half the time the longer ones are bent in the pack, or the shorter ones break whilst being done up - the rest of the time their heads get chewed up no matter how careful you are (not due to the wrong bit, just the metal on them being too soft).
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so true there's nothing like a good quality screw! :o
 
Try your local agricultural store, or specialist small hardware place* ;)
We've got one near us who have a huge range of screws and things (sold individually and in packs), and I think they sell a lot of odd sizes due to things like Farm Machinery/agricultural machinery sometimes harking back decades.
Alternatively somewhere that does restoration work might be able to help ;) (i think whitworth was used in steam engines and cars at one point).
A quick look suggests if it is whitworth thread it'll be either a BSW or FSW thread.


Jas, I tend to buy our screws from Screwfix these days, their Turbogold (or similar) seem to be much better when it comes to general wood screws (sharp, strong, good thread), combined with decent screwdriver bits and it's worth paying a bit extra (I don't think i've had a single one break on me, even when driving 6 inch screws, unlike Homebase where i've had 1" screws snap).


*Unfortunately becoming rare as they can't compete with with the likes of Homebase on general stuff (but often have experience staff and odd stock).
 
Werewolf said:
Try your local agricultural store, or specialist small hardware place* ;)

*Unfortunately becoming rare as they can't compete with with the likes of Homebase on general stuff (but often have experience staff and odd stock).
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Yep, all but one has closed in this town, and the last place was oddly enough somewhere I just didn't think of until last, lol. But they did have a couple :)

We used to have a great agricultural store that did just about everything you could imagine fixings wise :(
 
Dano said:
Arrr, that be whitworth.

(Darn old fashioned threads on modern equipment)
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Plus the fun of sending the apprentice off to the stores for "ten yards of Whitworth thread".


As PhillyDee says, Metric is easy as it's the outer diameter (roughly) of the bolt shaft, and thus the size hole you need to drill.


M
 
you think you have got your head round bolt sizes and threads sizes and then you come across the even more silly types of Nuts/Bolts...such as the ones the Americans liek to throw in there, why do they always have to do things differently :(, been caught out a few times by those annoying types
 
stryder said:
hi
i know this is a strange thing to ask about on the forum but does anyone know for sure how bolt,nuts and washer sizes are worked out? eg.M6,M12,M16.etc
does it go by the diameter of the bolt shaft or the size of the head or the length of the bolt? and will an M12 nut and washer fit an M12 bolt?
i know this probably a daft question but its one of those things you either know or you don,t:confused:
Click to expand...

M6 bolt is about 6mm in diameter, M8 about 8mm etc. M6 nuts fit m6 bolts. M6 washers will fit over an m6 bolt so a bit bigger than 6mm.
 
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