Evening all, I'm looking to fit a tap on my oil feed pipe, just below the oil tank. The tap has a female thread at each end. The thread is BSP, and I think is parallel, rather than taper (but I don't think that matters, as I'll explain.)
At the lower (engine) end I plan to use a fitting to which I can attach the oil feed tube with a jubilee clip. That fitting has a 1/4 bsp taper male thread which screws up into the female in the tap.
At the top (oil tank) female at end of the tap will screw onto the filter, which has a 1/4 bsp taper male thread.
The photo demonstrates.
My understanding is that it's okay to screw a male taper thread into either a female taper or a female parallel. I believe either arrangement should give a leakproof seal, provided ptfe tape is put on the thread. Obviously no sealing washers will be involved, as there will be a gap between the shoulders of the threads. The seal is provided by the threads tightening onto each other (assisted by the ptfe tape.)
My question is this: as I'm rattling along on my old B40, would the vibration be likely to result in the threads loosening? Any thoughts would be appreciated. Thanks very much.
Phil
Phil
in our use of BSP (or WST, our own standard), the British standard is a greater tolerance than our fit, so for train brakes we use a WST tolerance.
normally the parallel threads seal at the ends of the pipe and into the tap body via a fitting. the taper seals on the thread. We use Loctite red 542 to seal taper plugs into parallel holes likewise taper fittings into parallel holes . reason being, its easier to machine parallel threads on machines and to maintain depths and tolerances, not critical with plugs but is when you want the fittings to point in the same direction.
these fittings are for vacuum and or air connection.
we ordered taper plugs from a supplier plain brass, they supplied chrome plated plumbing fittings, made undersize to allow for plate, they stripped the plating and sent to us. British Standard greater tolerance meant these were like the proverbial ***** in a shirt sleeve.
ln olden days it would have been Hermatite and hemp, aslong as the orientation is ok , you use enough tape to position.
with the loctite it is a semi permanent seal so can be undine if needed. best thing to do is try ptfe tape or Loctite may break down with petrol so be warned.
I tend to use liquid ptfe from screwfix nowdays.
I tend to have the same sort of issues on my air compressor and air tool connections but PTFE tape always works reliably preventing any leaks even at 100 psi. Sealing in oil is much less demanding. The PTFE tape on the threads should definitely stop the connectors from coming loose!