I need about 50mm of coax hardline. I don't have any at home, but I do have a lathe, some copper, and some teflon stock.

Can I make my own coax hardline on the lathe? According to my calculations, for a 1mm center conductor, and a dielectric constant of 2.02 (PTFE), the outer conductor should be about 3.27mm for 50 ohms impedance.

I have a 3.25mm drill which should be close enough.

Would this work?


It's for building this antenna:

enter image description here

The antenna is simply a turnstile antenna, for 1.7ghz. hardline is used for support.

  • \$\begingroup\$ Try it. (Copper machines oddly. I have heard that the best lubricant/coolant for it is, oddly, milk). \$\endgroup\$ Feb 26, 2020 at 18:49
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    \$\begingroup\$ @BrianDrummond I found a reference: The Machinist's Bedside Reader by Guy Lautard is mentioned in Machining copper on PracticalMachinist.com as containing the suggestion to use milk. \$\endgroup\$ Feb 26, 2020 at 19:10
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    \$\begingroup\$ See also groups.google.com/forum/#!topic/rec.crafts.metalworking/… (about 8 messages down) ... another reference to Lautard. \$\endgroup\$ Feb 26, 2020 at 19:14
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    \$\begingroup\$ I am sure there are coaxial cables w/ PTFE insulation. Just check tne disassembled stuff around you. \$\endgroup\$
    – fraxinus
    Feb 26, 2020 at 19:26
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    \$\begingroup\$ Id' honestly just go with coaxial cable as waveguide, and for mechanical support, use styrofoam, or some other foam that isn't especially conductive. \$\endgroup\$ Feb 26, 2020 at 22:33


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