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Hi all,

A few months ago I spent quite some time hunting the internet to find an exact copy of these old screws for the early cars.

I did’nt find a single thing unfortunately but had some great people help me out with some alternatives.

Has anyone found any before?

I’m pretty sure they were available in the old Tamiya maintenance boxes too?

I’m after, we’ll as many as I can get but enough to do 2 chassis restorations.

G1 screw below

They look very similar to old meccano screws. I have to look at work. How many screws you need? If I can find and order.

Hi Stingray,

Let me know how you get on and if you pick any prices up first mate. I'm very interested if you can find some.

Honestly I would take 50-100 if they weren't ridiculously priced.

For the sake of anyone else looking in their stash i'd take what anyone could spare

I will try to find. look on the bay for vintage meccano. they are 4mm to. PM me Monday morning.

A couple of conceptual errors here that I really wouldn't want to see become accepted:

1 - you don't measure machine screws like that, nominal length is from the underside of the head to the end;

2- Meccano screws are absolutely not a direct replacement - they are BSW 5/32 (3.96875mm OD and 32tpi), the G1 screws are M4x0.7mm (36.285etc tpi)... although possibly you've got them confused with the "3mm" fasteners on really early kits (like the Cheetah & original XR311) that are actually UNC 4-40 ... although (again), the "4mm" fasteners on those kits were M4x0.7 so probably not...




I've got just the one screw this size & TBH I don't really want to give it up (not that one would really help you out anyway) ...

The M4x0.7mm bit is easy - so having something that performs the same job mechanically is no problem - but the visuals are a lot more difficult ... "slotted pan" is close to the right sort of head, I say "close" because the dot means the original G1 is JIS (Japan Industry Standard) - presumably the slot profile is subtlely different (like the not-Phillips X-head screws).

Length - you can have too short (10mm) or too long (12mm)

Plating is an issue, yellow Cadmium passivation seems to be a thing of the past, the only option being BZP (bright zinc plated). Different materials (stainless, brass) don't really help.

I did quickly Google home Cad plating - apparently there are "safe" (cyanide free) home plating kits, if I had a need for a lot of close to genuine looking G1 screws that's the path I'd go down - lots of the two closest wrong length (M4x0.7mm x 10mm + x 11mm) BZP slotted pan screws & Cad plate over the existing zinc... though I'd probably live with the plain BZP or brass TBH

Thanks for the info Jonny, I ’ll look at the close matches when I get in front of the computer but when looking around I did see some very similar, even emailed a couple of company’s that specialised in machine heads, but kind of gave up after I’d put many hours in.

Yes, I measured like that for the common Joe to get a perspective of overall size, not particularly for its specification, but maybe both would have helped. I guessed someone would grab a ruler and just sit the whole thing beside it.

On the zinc playing side. Great idea, I have plated before and do have a mini kit tucked away somewhere, not sure how useful that’d be now though, but I did seriously consider refurbishing the small stash I have. It was some years ago and don’t recall the yellow passivation vs bright zinc plated. I definitely know I passivated the zinc plated items though, I can’t recall how long but a quick dip and it worked a treat.

I recall I was restoring a Renault 5 GT Turbo (real one) completely standard spec and rebuilt engine with fresh refurbing bolts and clips. Particularly the carburettor accessories.

The problem being can I refurb the machine slots to look good, but I’ll give it a go if necessary. I guess like all these little projects, a plating kit will cost £60 upward and quite a waste if I go no further than a handful of screws I have.

Great info and great discussion

Thanks Jonny. I thought that meccano screws were metrical size.

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VCR wrote:

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You're going to have to be a bit more specific than that ...

As I do not have the original I did not want to be specifying the replacement (because I may be wrong). ... check these, DIN 84, ISO 7380, ISO 7380 TORX, DIN 7985, DIN 7985 TORX ....

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