Odd screw size on Amoeba Stem

[Russell]

No 1 son has decided he would like to ride around his local woods so 'please Dad can I have my mountain bike?'  It's been partially dismantled in the shed for the best part of a decade so needed some work. 

2 of the 5 screws (3 for bar cap and 2 for steerer) for the lurid green Amoeba stem were camming out (5mm hex) and were very difficult to tighten.  But they measured 6.8mm diameter, far bigger than the 5mm I would have expected and bigger than the 6mm I then assumed.  Therefore i couldn't replace them so mixed them up so there was at least one good screw for each function.

What thread would they be?  Any thoughts for a solution?

Thanks

[Feanor]

6.8mm Major Diameter is consistent with an M7 screw according to the tables I just looked up online.
Comes in different thread pitches, so you'd need to use a thread gauge (or mesh it against known screws ).
Might it be that?

[Brucey]

M7x1mm screw threads are used on quite a few stems, and these bolts are commonly ones that go rusty and really let the bike down, amongst other things.  I recently discovered that SJS sell M7 x 1 screws in stainless steel, so these bolts can be replaced with something better if necessary.

cheers

[Russell]

Thanks, I didn't realise that M7 was a standard size.  You live and learn!

[Jurek]

Laverda Iota inlet manifold.
The only place I've ever encountered M7.

[Brucey]

https://www.sjscycles.co.uk/nuts-bolts/jtek-stainless-steel-stem-bolt-m7-x-20-mm-pack-of-4/

M7x1 is also found in split-rim alloys , and head studs in some obscure Italian car engines, amongst other things.

cheers

[Nightmare-1]

https://www.sjscycles.co.uk/nuts-bolts/jtek-stainless-steel-stem-bolt-m7-x-20-mm-pack-of-4/

M7x1 is also found in split-rim alloys , and head studs in some obscure Italian car engines, amongst other things.

cheers

Split rim compomotives.
And some older Citroens, as I found out.
CX, BX, Xantia, XM to name a few.

They also used odd sized heads on the M6 bolts, some 9mm others 11mm.
On larger bolts they used 16mm instead of the more common 17mm & what size socket is missing from nearly all socket sets?

Yep! You guessed it 16mm.
£150 on a nice socket set (1/4", 3/8" & 1/2") and I still had to buy TWO 16mm sockets as one fitting needed a deep socket.

[Brucey]

Tool sets are a law unto themselves.  I bought a couple of sets which are small enough to keep in the car, handy enough to be useful; a lot of 3/8" drive sockets (long series, spark plug and short series sizes), ratchet, extension bars etc, screwdriver bits, allen keys and combination spanners, all in a blow moulded case at a reasonable cost.   I intended to try and squeeze any omitted tools into the same case so the whole was a useful collection.  Some parts of the kit were good; for example every mm size from 6 to 19 in short series 3/8" drive sockets, full hex. Other parts of the kit were bizarre; so combination spanners in 11,12,13,14,15,16mm sizes were present, which meant I had to add 8,10, 17mm sizes.  8,10, 17mm sized combination spanners wouldn't have been the ones I'd have left out!

cheers