Help identifying pipe fittings

[dom]

I want to use a stainless steel heat exchanger (intended for a Vaillant boiler) as a pre-heater as part of converting a diesel vehicle to svo (straight vegetable oil).

So I need hose tails to couple between the threaded flanges on the heat-exch and the fuel and coolant hoses on the vehicle.

I've been through my box of plumbing bits, and found the following matches:

2 (male) threads on the heat-exch match the nut used on 15mm compression fittings 2 (male) threads on the heat-exch match washing machine hose couplings

Now I need to look these up in a catalogue to buy hose tails - what are these 2 sizes called please?

[Lurch]

On Sat, 04 Aug 2007 11:51:25 -0000, " [e-mail]" mused:

1/2" and 3/4" BSP.

[dom]

Cool - thanks!

I kind of vaguely recalled they were - but doubted myself.

Are they defined by the OD size of the pipe they're usually used with

- as 1/2" and 3/4" doesn't seem to relate to any dimension on the threads themselves?

[John Rumm]

Defined by the inside diameter of the pipe they were traditionally used with IIRC.

[Roger]

The message from John Rumm contains these words:

I think that was thick walled iron pipe.

1/2" and 3/4" BSP both have 1.814mm pitch (14 threads per inch) and major diameters of 20.445mm and 26.441mm respectively.