I have a heating oil tank which is filled up by connecting to a threaded male inlet at the top. I need a new lockable cap for it. The thread is parallel-sided (i.e. not tapered)
I assumed that the thread would be 2" BSP. Having bought an appropriate cap (SpinSecure) on the internet, however, I discovered that it would not screw on. The cap female thread was too small.
So I measured the tank's inlet thread dimensions using some digital calipers. These dimensions are as follows: Outer diameter (thread crest-to-crest) =3D 60.4mm Inner diameter (thread trough-to-trough) =3D 58.0mm
I estimate the measurement error to be =B10.2mm.
I also measured the distance from the 1st crest to the 9th crest to be
19.12mm so there are eight threads in 19.12mm (=3D 10.63 threads in 25.4mm or 1 inch).Anybody any idea what thread size this could be?
When I looked up the 2" BSPP date it said Outer diameter (thread crest-to-crest) =3D 59.6mm Inner diameter (thread trough-to-trough) =3D 58.0mm