The Rev counter is held in with 2 bolts.

I need two slightly longer than stock bolts for a gauge cluster I'm installing. I contacted mini who told me they're m4 bolts.

I bought some m4 but they're nothing like these. So. Anyone any idea which one the bolt on the left is? The one on the right is the m4......

 

Any well stocked hardware store has those most likely. They surely have the gauge for telling you thread count and size.

 

At the hardware store test fit a couple of nuts to determine which threads are correct, then buy bolts for that size nut.

 

I took it to a bolt specialist near me and they said they can't identify what it is as the thread isn't like anything they've seen before...

 

Maybe it's an SAE(U.S.) bolt? In the U.S. we commonly have SAE and metric readily available in hardware stores. Is it the same in the UK?

 

I'm honestly not sure, I don't know a lot about types of bolts.

I would have thought that a shop that specialises in bolts would have been able to identify it, but they said the thread pitch isn't like anything they've seen before :/

 

I would think so, but I don't know how common SAE bolts are over there. Maybe rare enough that they overlooked it? Any pic of where the bolts go?

 

It sits in to hold the Rev counter in place.

It's longer bolts for this...

http://www.realoem.com/bmw/enUS/show...diagId=03_3003


And this bolt... (Number 4)

http://www.realoem.com/bmw/enUS/show...diagId=62_0394

 

Most "true-value" stores have lots of bolts...and nuts....usually in cases that pull out...
You sometimes need to change the head style...but can usually get most any length you need with threads as needed.

 

There are two metric thread pitches, coarse and fine. The one on the right looks fine, so the left should be coarse. That still doesn't explain why a bolt specialist in the UK couldn't identify the thread, or have a longer version.

 

I believe the one on the right is a standard m4 bolt.

The one on the left is the original bolt from the car. I ordered another standard set to confirm and they are the same.

I'll have to try somewhere else but the guy did explain to me why he hadn't seen anything like it before, he measured it, described the problem but it was about a month ago and I've just got back round to looking for bolts again and can't remember why he said he'd never seen them.

This place can actually make any bolt but obviously would cost a lot. The head I'm not too concerned about its just getting the thread right.

I've got a micrometer so I'll take some measurements and post them up, see if anyone can advise!

 

Then they're not much of a specialist

I'd bet money that's a thread-forming screw for plastic. Does it thread into plastic on the dash? Measure the diameter and pitch (between 10 threads and divide by 10). Looking at the pic I'd guess at 1.2 mm.

 

https://www.boltdepot.com/fastener-i...fasteners.aspx

 

Goes into a metal plate that sits under the plastic cover on top of the dash.....

 

Length..



Thread width



And width

 

The one on the right is a bolt. The one on the left is a screw. A sheet metal screw. All though what it threads into may look threaded it's not really only probably a thread in a half and that is formed when the screw is first installed. I don't think you will ever find a nut to thread onto that screw.

 

If it is an inch size from the U.K., it could be either British Standard Whitworth (BSW), or British Standard Fine (BSF). BSW is a coarse thread (less threads per inch), and BSF is a fine thread (more threads per inch). Also the thread form (angle) is different, @ 55 degrees included angle for BSW/BSF, as opposed to 60 degrees for SAE or metric threads.
"/\" is the thread form.

I would have thought that it would be a metric thread, tho, on a MINI.

 

This is where it goes into....

 

Think somebody grabbed a replacement bolt from their tool box in at some point in a prior job.....found something that "kinda fit"? Maybe the threads were bad, or who knows....
To have two bolts right next to each other on a car, produced on a modern production line that are dramatically different, and one of them "unique"....hmm...sounds like the simplest explanation is right...
The fine threads might have been stripped....so somebody grabbed a course threaded screw of the right length...screwed it in,letting it make new threads....hence it looks a bit like a self tapping thread...
Bet they said/thought... doesn't matter...this bolt is usually never touched in the life if a car, bet it will never be touched again...
My take...
You are WAY over thinking this find the right bolt/screw thing...it's not the space shuttle or a car that will be put into a museum...find a bolt/screw that kinda works...and reassemble it...
A mechanic trick is to dab so RTV silicone on the threads as you screw it in...it will act as kinda a lube and dry as kinda of a lock tight ...preventing it from backing out unless you take it out...learned that trick from an aviation mechanic.....often gets used in general aviation planes that are decades old that get many parts removed, and put back on EVERY year for inspection....do that for 40+ years...and everything gets loose.

 

I think people are misunderstanding.

The bolt on the left is the correct bolt. Their was two of them in the car. I ordered another pair from mini and the bolt on the left is what I received another two of.

What I needed was the same bolt but about 10mm longer to install the genuine gauge pod from mini.

Mini themselves recommended a m4 bolt. When I ordered it it was completely different and that's what's shown in the picture. The m4 bolt won't come anywhere near.

I understand that this isn't a space shuttle. I understand that in reality it doesn't make any difference what bolt is used providing it holds. BUT. I'm one of these people that likes to use as many original parts as possible, and have things fit and work propper melt, rather than just "chuck anything together that might just hold it".

I really didn't think it would be this much of an issue to try and figure out what it is that's holding this in

 

http://www.realoem.com/bmw/enUS/show...diagId=62_0394

Is it bolt/screw #4 in the diagram?

 

Yeah, see the reply number 8 above haha

But I need them about 10mm longer for fitting the gauge cluster (which is also shown in number 8 above but unfortunately just lists the parts as a "fitting kit" instead of individual items).

 

I couldn't resist and pulled mine out to measure. It's an M5x1.23mm or 1.25mm thread forming screw. Extremely odd size, although it is a known size for thread-forming screws.

If you absolutely can't use the originals (mine had over 10mm of thread engagement so you might be fine using them even with fewer threads) I'd try a #10-24 and see how far it'll go without binding.

 

100% can't use the originals. I'll take this information to my local bolt/screw specialist and see if they can help from this though! Thanks!!

And just to show you how much room I have once the bolt is in....

 

You're right, not much left there...

Every car has to have some sort of custom made Frankenscrews, looks like you found one! Why they couldn't have just used a regular M5 is beyond me...