Taper port question
Taper port question
(OP)
I know that it is common to use a taper external (male) thread with a parallel internal (female) thread for a hydraulic joint.
Is it possible to use the reverse, a parallel external (male) thread with a taper internal (female) thread.
More specific, would it be possible to create special taper tap so I can use a small standard 4mm metric set screw as a plug.
Thanks in advance
Nickjk





RE: Taper port question
Ted
RE: Taper port question
From: http://
<<<<Jointing threads: These are pipe threads where pressure-tightness is made through the mating of two threads together. They always use a taper male thread, but can have either parallel or taper female threads. (In Europe, taper female pipe threads are not commonly used.)>>>>
From: http:
<<<<Now we are back to the use of the male external Rp parallel British Standard Pipe "Taper" (BSPT) screw thread with the female internal R tapered British Standard Pipe Taper (BSPT) screw thread to concentrate the pressure at one point and create a mashed together thread and a dry seal.>>>>
This is what I want to do but I have not found the parrallel male and taper female anywhere else during my research and not sure if it was an error.
Thanks
Nickjk
RE: Taper port question
Ted
RE: Taper port question
Parallel male into taper female has less chance of working.
Use parallel/parallel and PST.
Mike Halloran
Pembroke Pines, FL, USA
RE: Taper port question
I need to come up with a miniature way to plug an hydraulic passage.
The plug needs to be easily removable and fit inside a port.
The smallest 1/16 R is too large, need something around 4.5mm.
Mike I am quite surprised by your response. Just because you do not agree with something does not make it stupid. This is not a method I have ever used but I am trying to keep an open mind to research found.
Nickjk
RE: Taper port question
Offended by 'stupid'?
Okay, it's lazy; saves a trip to the local Swagelok dealer to get a proper adapter.
The only US application of tapered male into straight female of which I'm aware is grease fittings with 1/4-28 threads. Small hex plugs and grease nipples are available.
Not quite common in the US, but available and just a little bigger than 4.5mm, is 10-32 straight threads. They're traditionally sealed with a flat gasket, but PST works better. The common plug for this series looks like a cheese head screw, and is usually the diameter of a pan head.
As to your original idea of using a straight thread setscrew into a tapered thread hole, I wouldn't do that, because you're basically trying to make a seal against the end of a thread, where the shape is not specifically controlled. I might be tempted to use a cone tip setscrew run into a straight thread hole with a countersink at the bottom, or maybe a flat bottom. ... but I'd be more comfortable using a headed screw and sealing on the flat face under that.
Above a couple hundred PSI, I wouldn't do any of the above. I'd probably use a Lee Plug in a reamed hole.
But you haven't specified a working pressure, or a fluid, or a body material so far...
Mike Halloran
Pembroke Pines, FL, USA