Where Can I Get These In Metal?

[ToraToraTora]

http://www.ebay.co.uk/itm/16-PCS-NUMBER-PLATE-BOLTS-NUTS-YELLOW-BLACK-SCREWS-FITTING-KIT-MOTORCYCLE-CAR-/291919794108?epid=2057251660&hash=item43f7c68fbc:g:BWMAAOSwHMJYI5-p
I keep breaking them off, often unscrewing them causing hassle. I can't seem to find them. The thread diameter is apparently 5.6mm, not bothered about the head or the length really. I suppose they must be non metric or they'd be M5/6 etc.. Any ideas anyone?

[Quoi]

http://www.ebay.co.uk/itm/NUMBER-PLATE-SELF-TAPPING-SCREWS-AND-YELLOW-CAPS-FITTING-FIXING-KIT-FOR-ALL-CARS-/332277628020?epid=624724931&hash=item4d5d4a3c74:g:9p8AAOSwXYtYw9xW

The right size self tapping screw might help

[Hymie]

Why not use M5 bolts (machine screws) of the appropriate length.
With a round head screw there will be little visible difference.
You could paint the screw heads if required.

[ToraToraTora]

quoi: they are for proper threaded holes, I don;t want to make new holes in metal.

Hymie: I would but they are not M5 or indeed M6, they are 5.6 mm so probably an imperial size.

[Hymie]

Having looked on-line, these screws are either M5 or M6 screws.

I suggest you offer the plastic screws up to a 5mm and 6mm nut to determine its correct size and buy the machine screws of the required length.

My bet would be that they are nominally M6 – it would be difficult to insert a screw with an OD of 5.6mm into a 5mm threaded hole.

[ToraToraTora]

I tried that hymie, M5/6 neither will screw into the holes.

[Hymie]

Well in that case it must be a ¼ inch imperial thread – you should be able to confirm this by measuring the thread pitch at 20 per inch, whereas the equivalent metric thread would have a 1mm pitch (25.4 per inch).

[ToraToraTora]

it's 5.78 wide and 24 Threads per inch as good as I can measure.

[Hymie]

Compare your measurements to those on an M6 machine screw, and there should be no noticeable difference.

Place the M6 screw thread against the unkown screw thread to check for a matching pitch.

[ToraToraTora]

I did that, it wont go into the threaded hole. It starts and then tightens up, I think the thread pitch is wrong.

[Hymie]

It could be a 7/32” British Standard Whitworth thread – see the table in this Wiki link.

The dimensions match your measurements – but finding such a screw might prove difficult.

https://en.wikipedia.org/wiki/British_Standard_Whitworth

[ToraToraTora]

thanks for your help, who'd have thought something so common in plastic is so hard to find in metal.

[douglas9401]

Would it not be easier to tap a new thread to suit a common modern screw?

[ToraToraTora]

no I don't want to make a mess of the car. These are very common in all sorts of cars, inexplicably, in plastic but I cannot find them in metal. They also fit on my motorbike.