Board logo

Seatbelt / harness mounts thread spec
jimgiblett - 25/3/08 at 10:58 AM

Anyone know the thread spec on seatbelt / harness mounts. Is it 7/16 fine?

My rollbar is going for powder coating and I will need to retap the harness mounts and thus need to buy the correct relevant size.

Thanks in advance

- Jim

mike smith1 - 25/3/08 at 11:04 AM

It's 7/16 UNF

Mike

[Edited on 25/3/08 by mike smith1]

bigrich - 25/3/08 at 11:07 AM

Yep 7/16 unf

jimgiblett - 25/3/08 at 11:20 AM

Thanks guys. I'll go buy a tap.

- Jim

BenB - 25/3/08 at 11:23 AM

It is very likely to be 7/16 UNF

but.......

some harnesses are now M8 12.9

Guess how I know this

It's normally quite easy to tell the difference between the two though as 7/16 UNF is significantly bigger than M8...

02GF74 - 26/3/08 at 08:00 AM

7/16 UNF (just a smidge over 11 mm)

now 8 mm?!?!?! that is 52 % of area of 7/16, no wonder the specify a stronger bolt!!!

Is opening out the harness holes to 12 mm and using 12 mm bolts a terrible suggestion?

jimgiblett - 26/3/08 at 09:13 PM

Yep 7/16th but the local factors want £20+VAT for the tap so I might just drop it off at the machine shop after it has been powdercoated to clean the threads out.

- Jim

iank - 26/3/08 at 09:55 PM

quote:
Originally posted by BenB
It is very likely to be 7/16 UNF

but.......

some harnesses are now M8 12.9

Guess how I know this

It's normally quite easy to tell the difference between the two though as 7/16 UNF is significantly bigger than M8...


How would that play at SVA? It specifies 11mm 7/16 or larger 8.8 grade as the minimum adequate spec. Even upping the grade to 12.9 isn't likely to compensate for that great a reduction in diameter [he says without running off and doing the maths ]

vinnievector - 27/3/08 at 07:27 PM

Some quick info on UNF 7/16 according to my trusted Zeus book.
if you want to tap a new hole you require a 9.9 mm drill if you , want to drill a clearance hole then you will need a 11.2 mm hope this helps .