I have been designing a prototype for a keychain that sprays perfume. I have a metal keychain piece which has a female thread and the plastic sprayer screws right into it and has a male thread.

I want to get these manufacturers ASAP but I need to be ensured it wont leak. I think I will switch my straight thread to a tapered thread, will that help?

What can I do to ensure that it will not leak?


  • $\begingroup$ wrap teflon thread sealing tape around the male part of the thread, screw the other part right over it $\endgroup$ – OpticalResonator Jun 1 '18 at 23:12

tapered threads are intended to be leakproof, but the degree to which they resist leaks depends on how tightly they are screwed together. This generally requires the use of a tool of some sort, as it is usually not possible to tighten a tapered-thread joint enough by hand to make it stop leaking.

For this reason you should instead use straight threads and a gasket like a soft O-ring which is trapped between the two pieces when they are screwed together. Unlike the tapered thread joint, these can be tightened enough by hand to be leak-proof.


Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.