13mm nut - what size screw?

[Richard10002]

I've mentioned it before - I need to replace some of my deck/hull fastenings, which are S/S slotted machine screw Csk slotted.

If the nuts are 13mm, (i.e. a 13mm spanner fits them, what size is the screw/bolt?) - or doesnt it work like that?

 

[Bajansailor]

Just looked up in my nuts 'n bolts chart, and it says M8 for 13 mm across the flats on the nut.

 

[Richard10002]

Many Thanks - couldnt sleep /forums/images/graemlins/smile.gif

 

[leomagill]

But if it's only 12.7mm(1/2") it will be 5/16" then could be unf or unc thread.

 

[nimbusgb]

Confirm - Metric 13mm is an 8mm shank.

 

[LadyInBed]

More than you want to know !

 

[Richard10002]

[ QUOTE ]
More than you want to know !

[/ QUOTE ]

Correct!!

I'll probably have to draw one and deal with the hole it leaves whilst I'm sorting this out.

Thanks to all

Richard

 

[LittleSister]

[ QUOTE ]
More than you want to know !

[/ QUOTE ]

Not quite! Fine as far as it goes - that funny foreign stuff - but wouldn't mind something similar which includes proper, British, threads. (If it was good enough to build an empire, I'm sure it'll suffice to hold up my gimballed brass effect anchor and seagull decorated nautical cuff-link holder.)

 

[Richard10002]

Machine Screw Specification - M8 x 25mm ??

Having drawn a couple of my deck/hull fasteners, how do I establish their exact specification:

so that I order the correct replacements from Sea-screw or whoever.

They would have been fitted to the boat when built in 1994.

The nut takes a 13mm spanner, (which suggests M8), the length of the whole thing is approx. 25mm, and the threaded bit is approx. 21mm. The outside diameter of the threads is approx. 8mm, and they take nicely an M8 nut from a Rolson Nut/bolt assortment I got from maplins, (trouble is, the maplin M8 nut is slightly bigger than 13mm, and wont take the 13mm spanner?)

On the basis that "if it walks like a duck..... " and all that, they look like

"M8 x 25mm Machine Screw Csk Slotted A4 Din 963"

Just making sure I'm reading this right as I dont want to come back to Malta with the wrong stuff.

Many Thanks

Richard

 

[duncanmack]

Re: Machine Screw Specification - M8 x 25mm ??

Richard

Pretty positive then that it's 8mm!

The other factor is is the thread 1mm, 1.25 mm (most likely) or 1.5mm.

Measure 10 threads. Do they cover 10mm, 12.5mm or 15 mm?

There you go!! /forums/images/graemlins/grin.gif

 

[sailorman]

Re: Machine Screw Specification - M8 x 25mm ??

Whitworth thread 1/4 or 5/16 /forums/images/graemlins/wink.gif

 

[AIDY]

Re: Machine Screw Specification - M8 x 25mm ??

Are you sure it's not UNF /forums/images/graemlins/grin.gif

 

[sailorman]

Re: Machine Screw Specification - M8 x 25mm ??

could be NFG /forums/images/graemlins/laugh.gif

 

[bendyone]

Re: Machine Screw Specification - M8 x 25mm ??

Go and buy a M8 nut and see if it fits.

 

[AIDY]

Re: Machine Screw Specification - M8 x 25mm ??

then pick some M8 machine countersink's up /forums/images/graemlins/grin.gif