7/16th vs metric equivalent...?

[jps]

Looking at some of what is specified in The Book it seems, to me as a novice, odd that some things are spec'd in metric: e.g. the M8 bolts to hold the pedal box in place. And some things are spec'd in Imperial:L e.g. the 7/16ths thread for where the top of the safety harnesses fit to the roll bar...

Any logic to this? Is it something to do with IVA?

I could understand if it was in relation to parts that come from specific donors - but these are parts that are not dependent on anything else (I would have thought?)...

[mgglep]

7/16 unf is the standard size for a harness eye bolt if you tap it to 7/16 then this leaves you open to use clip or bolt in harnesses

[ozzy1]

This is a standard used through the whole car industry for harnesses and seatbelt.Just remember that its 7/16 UNF & not UNC. These are easy to obtain from most suppliers.

[SeriesLandy]

Originally Posted by ozzy1

This is a standard used through the whole car industry for harnesses and seatbelt.Just remember that its 7/16 UNF & not UNC. These are easy to obtain from most suppliers.

I would agree, I bought UNC by mistake, welded them in and what a hassle to remove once it was put in.

[jps]

Originally Posted by SeriesLandy

I would agree, I bought UNC by mistake, welded them in and what a hassle to remove once it was put in.

Ah - I was thinking i'd have to buy some 20mm round bar and drill then tap it with a 7/16ths thread. Is it acceptable to weld nuts into the plates on the rollbar cross bar then? I'd assumed that it is specced into the book to a certain length (45mm i think) for an IVA related reason...

[alga]

The IVA manual states something along the lines that the threaded bosses cannot be welded to the side of the tube they're attached to, but rather have to be welded in. I think the plate bits hugging the bosses are there to satisfy this requirement.

[baz-r]

7/16 unf as said is the std mount for pritty much every seat belt out there in the aftermarket and doner world
its been chosen for a pritty good reason as its what is the best for the job in the standerds of bolt sizes, yes you could use a metric equivlent somthing like m11x0.75 but thats going to be even harder to find. the iva manual states what must be used or "greater" (min of 11mm dia iirc)
mr iva tester isnt going to be to happy with you messing around with you drilling out the ends of a seat belts to a bigger size to get a bigger bolt in so your pritty much stuck with 7/16 unf.
also you will get the right fixings with the belt/harness.

if any one gets stuck i may have 6 or so nuts somewhere in the abyss of my workbench pile o sh1te

[baz-r]

7/16 unf (20tpi) = 11.112mm with 1.27mm pitch closest metrics would be m11x1.0 or m11x1.25 both are not widely used as its an odd size
im not sure you are going to find any thing as easy to get as 7/16unf in the way of fixings in metirc