Weird threads used by Volvo in 1950/60’s
 

I was wondering if anyone knows if the Philips head screws used to hold the door catch mechanism into the door are available anywhere? The car is a 1960 Volvo PV 544. The screws in question measure 2.4mm dia x 1mm pitch x 12 mm long.
I can find no information on this size.

Correction sorry : 5.4mm dia x 1mm pitch x 12 mm long

Hi
I think you will find the thread form is unc
having a amazon 144 and 240 and 940
it looks like the change over was on the 240 look at the PCD on the wheels
140 inch 240 metric
hopes that helps

Not only Volvo, 'Salop Farmer'. Like us, Sweden used a mix of systems until quite recently. In fact, it is still possible to buy a pound of 4" nails from many a lanthandel (country general store) in the remoter parts of the country!

Regards, John.

I wonder if it might be a BA thread?

First off, a Volvo of that vintage would not be Metric so best to provide dimensions in decimal inches. A 5.5 mm major diameter is 0.2126 inches which is just short of the diameter of an #12 screw (0.216"). A 1 mm pitch is 25.4 threads per in; but, I bet it might be 24 TPI which would make it a #12 UNF screw. At 24 TPI you really need a pitch gauge to get an accurate measurement.

There is a British Standard Whitworth thread that is 7/32" (0.219") with 24 TPI that is very close. The 1800 used a BSW fitting on the oil line for the oil pressure gauge; but, that is the only BSW thread that I am aware of on Volvos.

Thanks 142 guy and everyone who contributed. I have imperial and metric thread gauges so will recheck sizes tomorrow. My car definitely uses a combination of metric,UNF and whatever this latest screw size turns out to be!!

I have remeasured the thread in imperial 7/32(0.218) inches diameter x 24 TPI x1/2” long. Does anyone know if I will be able to buy screws of this size ?

PVs were metric, Amazons imperial.

Sorted Screws ..... They are 12 - 24 UNC which I must admit I have never come across before! You learn something every day! 🤨 Thank the Lord for the internet!