Wheel bolt / stud thread identification

[Hesstondriver]

ive been given an axle assembly of an old car trailer, no identifiable features that i can see,

an M12 bolt goes in 1 1/2 turns , so i have deduced it is not M12 / metric.

what would it most likely be ?

cheers

 

[milkloss]

1/2" whitworth? Maybe locate a pitch gauge and work from that.

 

[C.J]

M12 is 1.75 mm thread pitch.

Freelander nuts are 12mm with 1.5mm pitch so it might be a popular stud / nut / bolt size.

 

[Hesstondriver]

M12 is 1.75 mm thread pitch.

Freelander nuts are 12mm with 1.5mm pitch so it might be a popular stud / nut / bolt size.

good point thank you

a bit of googeing suggests that m12 x 1.5 is common on trailers, coincidentally the same as used on some ifor Williams. i'll borrow one and try that first

 

[Kidds]

The alternative would be 1/2" UNF

 

[milkloss]

M12 is 1.75 mm thread pitch.

Freelander nuts are 12mm with 1.5mm pitch so it might be a popular stud / nut / bolt size.

never realised that three pitches are in use for m12: coarse, fine and extra fine.

 

[spanners and hammers]

think from memory some one will put me right the differenent pitches give different strenghts

 

[Sausage]

The finer pitch means it is not as deep radially. This means that the root of the thread has larger diameter and hence circumference. This combined with less metal loss in the troughs of the thread gives a larger shear area and hence a stronger thread for the same size bolt

 

[Ley253]

The finer pitch means it is not as deep radially. This means that the root of the thread has larger diameter and hence circumference. This combined with less metal loss in the troughs of the thread gives a larger shear area and hence a stronger thread for the same size bolt

Which ,gentlemen, is the reason your nice new machine built with the " one size fits all " iso metric threads, falls apart! Its too coarse for hard materials, and too fine for soft, really is the worst of two worlds! Even the Chinese are using metric fine now on stressed components, such as wheel bolts.