The female brass nut on the 1/2' pipe exiting the air conditioning condenser has a partially stripped thread so the male connector will not engage correctly (it starts then jams at a slight angle after half a turn).
Removing the condenser (done twice already for other work) is a swine of a job and rather than dismantle everything again I should prefer to attempt chasing (correcting) the damaged internal thread, which I can almost certainly do without removing the main radiator as well as the condenser. (Just the battery and one radiator bracket).
Professional thread chasing tools are expensive and I would first need to know whether the thread type is BSP, NPT or whatever. If I know that, I can make a chasing tool by cutting a (male) thread with a die on a short length of steel pipe. The vehicle is a 1991 Classic Range Rover so my guess is that the thread is BSP.
I have found a spare female nut that exactly fits the male connector and might be able to get one of the hydraulic services to identify it and supply the correct die but it would save a lot of hassles if I know the thread type in advance
Does anyone know for sure please? If convenient, maybe call me on 0248 433073
Both 1/2" BSP & NP are 14 threads per inch. The taper is near enough identical. In fact when drilling and reaming a hole to be tapped for a taper pipe thread the same reamer is used for both systems. Just get a cheap tap and run it down the damaged thread. Carbon steel pipe taps are cheap. high speed steel pipe taps are not.
Thanks for your advice. I should have mentioned that the threads are parallel - not tapered.
I actually did not want to use a tap because they remove metal, whereas a thread chaser only scrapes and reforms, but if I can't find or make one, yes a 1/2" standard BSP pipe tap will have to do. Due to the damage being so close to the entry, it will have to be a plug tap - not a taper or intermediate - that might be harder but Reese or another plumbing supplier might have one.
Took the beast to Lee & Thomas in Goulburn. The thread IS BSP and it took them all of ten minutes with a double-ended thread chaser to clean up the threads and reassemble the union. The picture shows the type used
I have ordered a 150 mm length of threaded 1/2" 304 stainless pipe and will cut 2 longitudinal slots at the end of the thread - this gives me the tool to fix any mid-threads in the future.
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