Lotus Elan and Lotus Elan Plus 2 Forums

To fasten the TTR Plus 2 driveshafts to TTR Diff Output shafts, I'm looking for some 7/16" high strength bolts. Caphead bolts give the required strength but access to the heads is extremely awkward. Alternatively hex head bolts would allow better access by a spanner. NAS bolts in theory are available in 1/16" graduations of gripe length, this would ensure that all drive is taken by the plain close fitting bolt shank and not the threaded portion. I think I need NAS 6607-13 bolts. Does anyone know of a reliable UK supplier of such things.
Regards
Gerry

Give "Namrick" a try. They should be able to provide what you need by post.

Cheers
John

Errm,
I just Googled Namrick & noticed that what they call "high tensile" bolts are bright zink plated.
That means that they are at most 8.8 quality.
In any case far better than B&Q bolts
The TTR cap head bolts are stronger being either 9.9 or 9.10 quality.
High tensile bolts are never plated in order to avoid hydrogen embrittlement.
(Sorry if that's a case of Granny's & sucking eggs)
It would pay you to phone first & find out exactly what quality they can supply in Hex.Head.

Cheers
John

Hi Gerry,

I'd be very wary of using 8.8 bolts that aren't plated in any way. They rust massively within 5 minutes of fitting them to anything.

NAS bolts are the way to go, but will be the most expensive bolt you'll ever fit to a car! Also try to fit 'K' nuts to these bolts. When I'm back at work tomorrow, I'll find out which supplier we use and let you know.

Alex

You could try AHC in Camberley:

http://www.ahc-camberley.co.uk/about.html

Paddy

Hi Gerry
In a ?How to build?? book I read recently, the author recommended Trident Racing Supplies.
I haven?t tried them my self but here is the web site.
http://www.tridentracing.co.uk/info/fastas.htm

Regards

Aircraft suppliers such as http://www.lasaero.com/index.php may be worth trying.

Gerry,
I used the TTR bolts but made a special key to do them up with. PM me if you want details.
Cheers
John

Hi all and thanks for your help.

I spoke to Trident Racing and they carry stocks of NAS bolts in sizes up to 3/8"

For larger sizes they can order as specials from the USA. In the event I've ordered their close toleranced, plated MS bolts. These are 120ksi as opposed to 160ksi for the NAS bolts. ?2 each approx.

Against a check calc, my first gear and diff ratio of 3.54 could in theory produce enough torque to shear these bolts. Thinking that racing starts are NOT a good idea.

In reality, if these bolts are torqued up to yield then drive should be by friction between mating flanges rather than just by the bolt shear area. Also, with an open diff there should be substantial torque sharing between both diff outputs.

In any case, I'm not sure what the weakest component is in the drive train. (outer drive shafts or hub to driveshaft key?) Anybody have this covered for a Plus 2?

Regards

Gerry