simondance · Oct 7, 2022

I'm looking for some replacement socket button screws (ideally in black oxide stainless steel) to replace the tired looking bolts on the roll cage.

To save me from taking one out, does anyone with a similar cage, know the bolt size? or better still, the part number?

thanks for your help.

Def90man · Oct 7, 2022

simondance said:
I'm looking for some replacement socket button screws (ideally in black oxide stainless steel) to replace the tired looking bolts on the roll cage.

To save me from taking one out, does anyone with a similar cage, know the bolt size? or better still, the part number?

thanks for your help.

Are they M12? Take one out and measure length and thread size then either the well known internet auction site or a few nut and bolt places have every size although not black. But a search tells you how to blacken them too if you fancy an experiment

miktdish · Oct 7, 2022

Stainless steel is 'soft' relative to hardened steel, the softness is because it is an alloy which contains (along with standard steel) Nickle and Chromium.
Looking at the application of these bolts, the main consideration is the 'shear strength' of the bolts. If the tubes (making up the roll cage) are steel (which I would hope they are) then they would act like a guillotine when you roll the car, so it is really important that the bolts you use to hold the cage together are as strong (or are stronger than) the cage itself.

The reason those bolts have oxidised is that they are made from a high tensile grade steel.
The hardest stainless you can get is A4-80 which is almost as hard as 8.8 steel.
I'd not reccommend even 8.8, if I were you I would go for 10.9 or even 12.9 grade HT bolts.

The Domed head set screws in your photos are commonly supplied in 10.9HT steel.
The length of a domed headed set screw is measured incorporating the head.
They come in a variety of sizes and lengths.
You could use a pair of calipers to measure the length and if you tell me what spanner fits the nut I will tell you what size the thread is.
When fitted you need to paint them to stop the oxidisation.

miktdish · Oct 7, 2022

@Def90man reccommending 'soft as brass' (A2) bolts to hold a roll cage tother is not a good idea (IMO) ...

Def90man · Oct 7, 2022

miktdish said:
@Def90man reccommending 'soft as brass' (A2) bolts to hold a roll cage tother is not a good idea (IMO) ...

He asked where to get bolts. I gave him suggestions.

Grebby · Oct 8, 2022

The length of the bolt does not include the head. The length is measured from the underside of the head to the end of the threads. ISO 7380

miktdish · Oct 8, 2022

Grebby said:
The length of the bolt does not include the head. The length is measured from the underside of the head to the end of the threads. ISO 7380

Yes it does, my mistake .... (well spotted @Grebby )

simondance · Oct 9, 2022

Thanks everyone for your helpful replies. Most appreciated

simondance · Oct 9, 2022

Miktdish on your recommendation I’ve just measured and then purchased the following.

High tensile grade 10.9 allen socket button head bolts.
Threads are metric coarse (most common).
M12 (12mm thread diameter) x 1.75mm pitch ~ 10mm allen key.
ISO 7380 Quality.

Will keep you posted with how I get on

simondance · Oct 30, 2022

Well this is depressing.

The new bolts are in, and they are already rusting!

Does this mean I have non-stainless steel bolts?

simondance · Oct 30, 2022

I made the mistake of buying black bolts (what I wanted), but I will have to look at stainless steel ones now.

miktdish · Oct 30, 2022

Stainless steel is soft, if you use stainless bolts they (a) will not rust so will 'look good' but will (b) shear in half when you roll the car so won't do thier job, consequemtly the roll cage with not do it's job and you will get crushed.
What you have fitted is the correct bolts for the job.
Yes, without any protection from water they will corrode.

Take one bolt out, wipe of the rust, coat the bolt witrh copper slip or a waterproof moly grease or Lanoguard grease and reassemble, tighten to the correct torque.
Spray the bolt with brake cleaner, wipe it dry and cover it with paint, hammerite would be good or any other direct to metal paint.

simondance · Oct 30, 2022

@miktdish - incredibly helpful. I’m going to do exactly this.

miktdish · Oct 31, 2022

Landrovers aren't really about looking pretty, they are functional, agriculturalesque vehicles. They look best when they are spattered in mud and have a slight patina that identifies them as a 'bit of rough'.
They are the big quiet lad at school, tough enough to be the bully but who isn't a bully at all. He's the one who plays #8 in the school rugby team and helps the neighbors when the snow comes.
He can't run very fast and he would never be described as 'nimble' but he always gets the job done.

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