nuts and bolts

For ease of maintenance in the garage and especially 'in the field' I want to have as uniform as possible fasteners. I want where possible to reduce the number of tools required , both in the garage and  in the pocket whilst competing.
I have chosen to go for A2 grade Stainless steel, metric ,button headed bolts, washers and nyloc nuts where ever possible.

Button headed so that I don't need two 12 mm spanners just one and an Allen key, so that the head has the lowest and smoothest profile yet the largest contact area and A2 stainless steel for corrosion resistance ( the more durable in A4 was excessive in spec. ( sea water) and cost!)(+ 30%)  and finally metric as it is the most commonly available size.

Finding all the fasteners required for the frame set proved relatively simple locally at Screwfix.com and even the counter sunk screw for the GasGas chain tensioner proved no problem via ebay.co.uk

As for length of fasteners each has been machined to an optimum length to leave a complete thread outstanding from the nyloc nut when the fastener is secured.

The most complex bolts to source have been the three engine mounts, although drilling out the frame to a metric 10mm was not an issue, I felt that drilling out the cast alloy mounts on the engine  cases was perhaps taking a risk and one that carried little or no value so I stuck with the ioriginal sized fasteners.
After several days looking i found Namrick.co.uk in the UK who specialise in imperial sizes for classic cars, they have something of most threads although some  are now in limited supply as traditional automotive threads are been discontinued even in the US.  There are in fact many stockists in the USA but import duties and fees proved prohibitive.

So 3/8 inch bolts and nuts were obtained eventually but unfortunately were not /are not available in Stainless steel in the correct lengths of circa 90 -100 mm so zinc plate and traditional hex heads  it is.