How do i know how big my nuts are ?

[big soft moose]

(yeah yeah we've done all the jokes already thanks)

Is there a set relationship between the outside dimension of a standard nut and what M thread it takes ?

I need to buy some replacement nuts on a machine and the only info ive been given (this is at work not on my own machines) is that they take a 22mm spanner, so can i work out the M thread from that , or do i need to send a minion back to measure the thread ?

 

[gerrybhoy70]

Hi BSM,

There can be a huge variation in the external nut size depending on the manufacturer, so I'd advise getting the thread checked.

Gerry

 

[Boatfixer]

Should be M14 thread if the table I found via google is to be believed....

Graham

 

[WoodAddict]

M4 = 7mm
M5 = 8mm
M6 = 10mm
M8 = 13mm
M10 = 17mm
M12 = 19mm
M14 = 22mm

I've never seen anything other than these dimensions on all nuts/bolts. Be careful if it's a foreign size thread though. The spanner sizes are very close but not quite the same and it's easy to round them off. :roll:

HTH

 

[Racers]

Hi,

I have M8 nuts that are 12mm AF not 13mm, on the exhaust clamps of my motor bike, but thats because its tight in there.


Pete

 

[jasonB]

Quite a few Japanese cars will have smaller AF size nuts than the list posted above and they are also often Metric fine pitch not metric coarse.

Always best to try and get a measurement of the major dia and pitch if you can.

Jason

 

[big soft moose]

this is on a BCS tracmaster 630WS commander scythe mower , which is made in the uk so it "ought" to be standard metric.

anoyingly the nuts arent listed in the exploded parts diagram so i cant check from that.

i'll try some M14 and see

nother question , these have gone missing because they vibrated off ( I beleive they were standard nuts), am i better off replacing them with nylocs or should i just put standards on and use threadlocker ?

(before anyone says eliminate the cause of vibration , on a reciprocating blade mower that isnt possible - they always vibrate like buggery)

 

[WoodAddict]

How close are they to the engine/motor/exhaust etc...... any area that gets too hot is no good for nylocks. The rubber part goes soft and doesn't hold liek it should. You're probably best to put a split washer in between the nut and a flat washer.

If it's not urgent then I can have a scrounge around at work tomorrow to see if we have any M14 stuff lying around. We've got a couple of trays full of big stuff that will never get used. We may even have a spare jiffy bag lying around :wink:

 

[Digit]

ISO metric dimensions are standard, but regrettably Japan for starters, seem not to know that
I have never found a difference from ISO with any other country.

Roy.

 

[big soft moose]

How close are they to the engine/motor/exhaust etc...... any area that gets too hot is no good for nylocks. The rubber part goes soft and doesn't hold liek it should. You're probably best to put a split washer in between the nut and a flat washer.

If it's not urgent then I can have a scrounge around at work tomorrow to see if we have any M14 stuff lying around. We've got a couple of trays full of big stuff that will never get used. We may even have a spare jiffy bag lying around :wink:

cheers mate but dont worry i'll buy some tommorow as we really want this back in battery asap as the grass is growing like nobodies buisness thanks to recent weather

the blade is about as far from the motor as you can get , but it gets quite hot from friction so maybe nylocs arent a good plan - i think we'l go with standards and thread lock - and maybe a dollop of superglue to be on the safe side

 

[dickm]

Dunno what they are called, but you can get nuts that have what looks like a cut in the side, which is then slightly closed up to distort the thread to lock in place. Guess you could do something similar on a nut that size with an ordinary hacksaw.

 

[MikeH]

You could try here:
http://www.numberfactory.com/nf_metric.html
Select the Nuts, Screws, Bolts option.

I take no credit, someone else posted it on this forum (can't remember who) in response to a similar question and I was so impressed I bookmarked it.

 

[OldWood]

Thanks Mike - the baton gets passed on

Rob

 

[Shrubby]

Hi BSM
The nut **** M recommended are called Aerotight. The bolt needs to be good quality though. Nylocs or a splodge of medium loctite would probably be OK
Matt

 

[bugbear]

(yeah yeah we've done all the jokes already thanks)

Is there a set relationship between the outside dimension of a standard nut and what M thread it takes ?

I need to buy some replacement nuts on a machine and the only info ive been given (this is at work not on my own machines) is that they take a 22mm spanner, so can i work out the M thread from that , or do i need to send a minion back to measure the thread ?

There are standard nuts, which have a standard relationship between AF and thread.

But there are also (quite commonly) non standard nuts.

So I think you're down to measuring, if you want to be sure.

BugBear

 

[andycktm]

Spring washers!

 

[Racers]

Castellated Nuts! :lol:

 

[big soft moose]

Castellated Nuts! :lol:

sounds like something you'd take penecilin for

spring washers didnt work - they were on before the nuts vibrated loose. You may be under estimating the degree of vibration these mowers output - think of a washing machine with all the load on one side