Hope people don't mind me coming with yet another question - I really appreciate the guidance that this forum has given me over the past couple of years.

I'm building a fuel tank, using 10mm compression fittings onto a mix of copper and stainless pipes. Naturally I need to connect this tank to the engine somehow! What would people recommend for fuel lines? I believe the normal 10mm nylon rigid lines are 10mm OD, not ID. Has anyone any pearls of wisdom to offer, or should I just fit an olive to the end of the metal pipe out of the tank and jubilee clip some 10mm bore nitrile hose over it? Obviously the latter would need adapting down to a standard fitting somewhere along the way.

10mm nylon will fit and work in a 10mm compression fitting.

Ah OK - with a sleeve inside to stop it collapsing? Much appreciated; I'll do that. Thankyou once again

I didn't use inserts and 16 years on, no leaks.
Depends on the quality of the nylon I guess .

you can use five piece compression fittings to join nylon to metal pipes. The most common error is not using the correct olives. Use stepped olive for nylon and barrel olives for the metal. Sorry if I am stating the obvious.