M10 bolts getting smaller?

[mgarym]

Hi all,
I bought some m10 x40 bolts today
and to fit them witm my 17mm spanner
and ratchet only to find tye heads were
15mm. I thought m10 bolt head sizes were
always 17mm or have they been changerd?

 

[SteSteSte]

6mm = 10mm
8mm = 13mm
10mm = 17mm
12mm = 19mm

(sorry, had to write it down to think about it).... Not that I know of, last lot I got were all 17mm, though its a few months back!

 

[mgarym]

yeah they have always been 17mm
when i found out ,i had to trek back across a ploughed field
and drive home for a different spanner and socket

 

[stew]

yeah you get (as far as ive seen), M8 and M10 with different size heads on them. Ive seen 16mm and 15mm M10's as well as the usual 17mm. same for the M8's.

im afraid i cant elabore any more than that!

 

[madkayaker]

i know that you can get reduced head size bolts. very common on cars especily the french

 

[mgarym]

I though maybe with high steel prices
the manufacturers were ruducing head size
to save metal

 

[madkayaker]

bit like they did with wit durning the war? prehaps there is starting to be a cost saveing

 

[Pete.]

Jap motorbikes have reduced-head sizes very often. M10 with 14mm hex, M8 with 12mm hex, M6 with 8mm hex.

A normal off-the-shelf M10 I would expect to have a 17mm hex.

 

[chunkolini]

This sort of thing drives me mad.
Standardise everything and be done with it.
Standards that aren't standardised? we may as well as go back to the imperialist system.
If we lived in a Marxist Leninist state there would be one size for everything.
ok it might never be in stock but we would know where we stand.
Chunko'.

 

[Sean]

which standard jap industry standard is M8=12MM etc, anyway all you need is a shifter or moleys

 

[welshpug]

French stuff have 16mm heads on M10 due to the smaller pitch threads, 18mm on M12.

 

[brightspark]

This sort of thing drives me mad.
Standardise everything and be done with it.
Standards that aren't standardised? we may as well as go back to the imperialist system.
If we lived in a Marxist Leninist state there would be one size for everything.
ok it might never be in stock but we would know where we stand.
Chunko'.

joseph whitworth standardised threads .they were imperial i must admit though metric is easier to measure than fractions

 

[Hitch]

Are they just bog standard 8.8 hex heads then?
Flanged head bolts are normally smaller.

 

[pedrobedro]

Jap motorbikes have reduced-head sizes very often. M10 with 14mm hex, M8 with 12mm hex, M6 with 8mm hex.

A normal off-the-shelf M10 I would expect to have a 17mm hex.

They are usually called flange bolts if they have a reduced size head. It's not only Japanese bikes, KTM use them as well.

 

[julianthegypsy]

We do have standards, it's just that they aren't always used because there are always situations where you need an odd sized bolt for odd sorts of reasons, and you can't regulate invention. Ferguson tractors had two head sizes for everything for the simple reason that Harry Ferguson wanted the operator to be able to do any job with the one open ended spanner supplied with the tractor. It only stopped when GKN started demanding huge premiums to make all these tiny bolts with huge heads! I'm sure any modern car mechanic would agree that life would be a lot easier if engineers were so considerate these days!

 

[mgarym]

Hitch I just asked for m10 bolts,and assumed they would be standard size
I tried m10 normal sized nuts and they went on without any problem so
the thread pitch is normal.
They weren't cheap either £4 for 10

 

[GrahamGKD]

We do have standards, it's just that they aren't always used because there are always situations where you need an odd sized bolt for odd sorts of reasons, and you can't regulate invention. Ferguson tractors had two head sizes for everything for the simple reason that Harry Ferguson wanted the operator to be able to do any job with the one open ended spanner supplied with the tractor. It only stopped when GKN started demanding huge premiums to make all these tiny bolts with huge heads! I'm sure any modern car mechanic would agree that life would be a lot easier if engineers were so considerate these days!

Interesting bit of history there.... Mr Ferguson could have just supplied an adjustable in the toolkit! Having said that, I was taught not to use adjustables because using the correct size of spanner gives you (very roughly) the appropriate amount of leverage for the size of bolt. I guess the same would apply to bolts with oversize heads.

 

[R Kraft]

Old Volkswagons used to come with a little tool kit with a couple of wrenches in it.
The nuts on the bolts were a different size from the bolt head,so that you didn't need two wrenches of the same size.

 

[Lawnmowerboy]

bring back whit!!! thankfully i have a filing cabinet full of all the washers nuts bolts pins studs all from my grandad from 50 years of ag engineering!!!

 

[rikrobson]

Went to my local ironmongers/hardware store/stockholders in town and got a 60mm M12 bolt for 70p. Even asked if i needed a nut. that was standard 19mm head on it