Metric fasteners

In 1982 the British Standards Institute (BSI) published PD6507. 'Guidance on metric screw threads and fasteners for use by model engineers'. I acquired a copy (the company I worked for had a BSI account). It specifies a range of metric fasteners etc scaled to represent full size e.g. Whitworth. So bolt head hexagons are not as normal metric.

It appears to have never been adopted.

I intend to use metric fasteners on my latest model but I'm having problems in finding small (2.5mm) hex head bolts. So far all I've found are in stainless. Plenty with socket heads but this is not in keeping with the model.

What do others, who've adopted metric, do ?

If you have a mill maybe you could machine the hex down to a better looking size to suit your model.

regards

I've bought more than once from this German company; example of their stuff;

GHW - Bare Steel Hex Head Screws for Modelling

There's a little 'Flag' icon in the top left corner to change the language. Nice products, with useful descriptions.

Hi Peter,

I tend to make studs and use nuts, and it isn't easy to find M 2.5 hex head bolts where I live.

Thor

Not come across them. There's a lot of useful looking stuff on their website and you can use PayPal. I'll give them a go.

i also use GHW mostly nuts but do have some hex head screws in stock for the odd occasion that they are needed. You may have a job finding 2.5mm dia steel for studs but I've made 20+ engines using 3/32" steel whick takes the M2.5 thread Ok.

If you don't want to but from mainland Europe then Polly Eng keep some of GHW's range.

Not sure what the BSI specifies but generally the GHW ones are one size smaller so M4 is 5.5mm hex etc. They are also fully machined with single chamfer so look a lot better than mass produced standard metric ones.

This shows M4 & M3 standard in the middle, GHW outside

Edited By JasonB on 26/11/2022 13:11:23

Here, in The Netherlands, we have this company: **LINK** (website unfortunately in Dutch only).

For instance, on this page of that site, you find small (starting M1,2 x8) metric steel hex head screws with high heads: **LINK**

Regards from The Neherlands,
Gep

Edited By Gep Engler on 26/11/2022 13:29:35

In case people aren't aware if you are using Chrome (and possibly Firefox?) then right clock in a web page and select translate....

Not sure if the same problem exists bringing stuff in from abroad, but my sister in law has had to give up sending presents to her granddaughters in Germany, the bureaucracy was impenetrable.

m2.5 studding is available at many sources on the internet just google it.

I prefer proper studs with threads just at the ends

Yes. But these are for through bolts with nuts on the other end holding brackets onto the frame. Would look odd having studding with a nut both sides.

Edited By Peter Howell 1 on 26/11/2022 17:32:36

Although quoted in Imperial dimensions BA is a metric system.

Peter, my comment was aimed at Dave Smith who suggested studding, that would look even worse for your use.

If long bolts are needed I make them from round stock and mill the hex with the aid of the spin indexer

Another German supplier that is quite good is Knupfer with a similar range of fixings

Edited By JasonB on 26/11/2022 18:45:19