We've been tasked with considering an existing design for coaxial bulkhead connector (breaching a pressure vessel).

One end of the bulkhead has a relatively common 'Microdot' / 'S-50 series' coaxial interface.

The other end has a threaded #2-64 (ANSI American thread) for the shield connection.

I'm looking for what type of threaded coaxial connector (like the S-50 or SSMA - but even smaller) that this smaller-end was designed to connect to.

Some likely misleading dimensions that pertain to the center conductor:

  • #25 AWG or smaller (0.02" diameter)
  • 0.037" (1 mm) or smaller center conductor insulator (core) outside-diameter

Yikes, that seems small...

It is also entirely possible that there is no standard-type connector, and that this was an entirely custom contraption (whose history and all relevant documentation was tossed-out with the fax machine).

Sorry, no pictures are available.

Anyone have any good suggestions?

Thank you and best regards,


  • \$\begingroup\$ What signal/spectrum/power is being passed? \$\endgroup\$
    – Andy aka
    Commented Mar 1, 2023 at 20:12
  • \$\begingroup\$ @Andyaka Nothing challenging. DC to ~2 MHz, low-voltage. Acoustic/Ultrasonic apps. 1:100 duty cycle (low power). \$\endgroup\$ Commented Mar 1, 2023 at 20:37
  • \$\begingroup\$ What kind of pressure, is there an IP rating? \$\endgroup\$
    – Voltage Spike
    Commented Mar 1, 2023 at 21:04
  • \$\begingroup\$ @VoltageSpike That's a property of the bulkhead design. My concern is the connection to it (which is at ambient). But if you're curious, let's say 10,000 psi /700 bar, up to 30,000 psi @ 150 C to maybe 300 C. \$\endgroup\$ Commented Mar 1, 2023 at 21:12
  • \$\begingroup\$ That is a lot, more than anything I've worked with! \$\endgroup\$
    – Voltage Spike
    Commented Mar 1, 2023 at 21:15

1 Answer 1


I compile lists of connectors. These are the smallest coax connectors I list:

None of them use a ANSI thread. Are you sure your connector has a #2 thread? If it's metric, it could be one of them.

  • 1
    \$\begingroup\$ Absolutely, 100% #2-64 threads. \$\endgroup\$ Commented Mar 1, 2023 at 21:15
  • 1
    \$\begingroup\$ By the way, thanks for the list. I really appreciate it. \$\endgroup\$ Commented Mar 1, 2023 at 21:26
  • \$\begingroup\$ The list is from my connector identifier utility. \$\endgroup\$ Commented Mar 1, 2023 at 21:54

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