Depends on the material used in the bolt, the loading it will be subject to and the environment it will be used in.
6mm bolt with 1.0 thread pitch
m6 is bigger
M6 - 81 = M6 - 92 = (M3 - 9)(M3 + 9) [difference of two squares]
190 miles taking this route:Take A556 (SOUTH) from Bowdon to M6 SOUTH. Follow signs.Take M6 to M6 TOLL in Birmingham, then continue on M6 to either M40 via M42 to London or M6 to M1 to London.
120 miles taking this route:Take M40 to The NORTH towards BIRMINGHAM (to M42, M6), from Stratford (via A46), to M42(N) (to M6) to The NORTH.Take M42 to M6 TOLL to The NORTH WEST, and then take M6 TOLL, around Birmingham, to M6(N).Take M6 to MANCHESTER, via either M56 (via A556 @ J19 on M6) to MANCHESTER and MANCHESTER AIRPORT, or via M62 (@ J21A on M6) to MANCHESTER (NORTH).
Coventry, West Midlands to Dumfries, Dumfries And Galloway is 248.3 miles taking this route:Start out by either going up to M6 to The NORTH WEST to BIRMINGHAM, or start out by taking A45 BIRMINGHAM.If you are taking M6, take M6 to M6 TOLL to The NORTH WEST. If you are taking A45, take A45 to M42 to The NORTH (to M6), and then take M42 to M6 TOLL to The NORTH WEST.Once you are on M6 TOLL, take M6 TOLL, around BIRMINGHAM, back to M6 NORTH to STAFFORD.Take M6 up to SCOTLAND, where you will take the first exit (J22) onto A75 DUMFRIES.Take A75 to Dumfries.
These are standard metric screw/bolt sizes. You should be able to find them at a local Hardware Store. Such hardware is also available online.
135 miles taking this route:Take A595 CARLISLE, from Whitehaven, to M6 in Carlisle. Follow signs to M6, and then follow signs to M6 to The NORTH.Take M6 to The NORTH to SCOTLAND, where M6 becomes A74(M).Continue on A74(M) and M74 to Glasgow.
410 miles taking this route:Start off on either M1 to The NORTH or M40, from London.If you start off on M1, take M1 to M6 BIRMINGHAM at J19. Then you will take M6 to M6 TOLL to The NORTH WEST. If you start off on M40, take M40 to M42(N), and then take M42(N) (briefly) to M6 TOLL to The NORTH WEST.Once you are on M6 TOLL, take M6 TOLL, around BIRMINGHAM, back to M6(N).Continue on M6 up to A75 STRANRAER, in SCOTLAND.Take A75 to Stranraer.
M6 destroys CLK in 1/4 mile
The 2010 BMW M6 has 40 valves.