Rivnut sizes

DavidH · #1 15th February 2008, 20:17

OK so this is gonna be a real newbie question.

Just getting some bits together before the kit, alot of the rivnut tools I have seen only do up to 6mm I seem to remember a post suggesting that 8mm was needed for something. is this the case and what are they for? Oh am assuming I need steel rivnuts not Ali.

David.

limpabit · #2 16th February 2008, 05:08

Hi David.

These rivnuts can be funny little buggers. If you can, I would drill and tap if possible. I think silver ones are for ali and bronze coloured ones for steel.

I've only used the M6 ones.

eaa53 · #3 16th February 2008, 08:51

I know Mark likes to use this little blighters and is quoted for the reasons why in public.
From an engineering perspective I believe that the amount of metal removed from a small cross section tube weakens the structure, and add that many time along its length you will understand my concerns.
Like the spline issue this is a recommendation and Marlin preferred method.
However, I side with Limpabit on this. Personally I use hardened self tappers, non-rusting, chromed flanged headed where I can to spread the load. The panels can be glued in to place as well so the self tappers can be very secure, your build your choice.
Remember the structure you are placing the rivnuts into is generally the structure that surrounds the driver!

craig · #4 16th February 2008, 08:52

I only used m6 and m5 and also only used ali nuts! It was suggested that steel be used in the floor but it wont make any differance if you use plenty, as mine was always going to be over the top on power I used them every 40mm or so instead of the rec 100mm to help with rigidity

Craig

alackofspeed · #5 16th February 2008, 10:22

I used m5 rivnuts, and not a great number of them - basically the top and bottom covers for the centre tunnel. Most other areas I bonded and riveted.

I perhaps went a bit OTT, but to try and help with stiffness to complement future power upgrades, I have 2 no 1.5" CDS cross braced tubes running between the GRP body side panels and aluminium skin.

craig · #6 16th February 2008, 12:15

Just realised we are talking rivnuts! I was thinking rivets! Well I used only m5 and a few m6 rivnuts and as John bonded and riveted the rest every 40mm

Craig

John, what are you doing posting when it's weather like today and your off work?? I presume its the same down there as up north not a single cloud to be seen?

alackofspeed · #7 16th February 2008, 17:31

Craig, fear not I've been to Devon and Somerset today, visiting uni mates. Car has 600 miles on it already!

I posted earlier, just after quick early morning repair - I've cut a section out of my diffuser, and repalced it with mesh (not sure it'll stay like this, but it looks okay), having scorched it (it was smoking, and probably on its way to catching fire....) to oblivion with the hot exhaust.

DavidH · #8 16th February 2008, 23:28

Thanks all,

I guess that everyones done it slightly differently then.

I think then I will plan to use rivets for all the main panels and start off by trying to drill and tap the chassis to allow for bolts for the centre tunnel panels. If that doesnt work I can always drill larger for rivnuts afterwards.

Glad to hear that things are going well (600 miles is pretty good going) with the car now its licensed. Guess you have been able to banish fears of a recurrence of the cv joint having gone alot further now.