Anyone recommend a good quality straight edge

[seanr28]

Something like an engineers rule for checking flatness of heads / blcoks etc please?

[Gordo]

Check out your local engineering supplies shop.
There should be several listed in your area - can be quite pricey, though, so make SURE you look after it - it should come in a substantial case!
Check the length of the head diagonal and round it up - I would expect a 450mm to be a bit short but a 600 is going to be a fair bit more expensive, so if the smaller will do the job, get it.

Hmmm. not too bad, maximum deviation 1 thou over 24" - Buy Veritas Steel Straight Edge from Axminster, fast delivery for the UK

In Metrology we used straight edges that were to 0.001mm ove a metre - but they were EXPENSIVE!

[leesturbo]

nice one gordo

[M B Automotive]

glass!

[seanr28]

Got a Veritas one in the end cheers!

[djbrowney]

Just go buy a level from b and q