Phil Nelson may have a parts chassis
http://antiqueradio.org/halli07.htm

Hey, small world. Rich already contacted me, and I did have one other bit
that he's looking for. But my junker is missing the things he mentions in
this thread, so I suggested he post here. Surely I can't be the only one on
Planet Earth with a junker SX-42 :-)

Knob style binding posts
http://www.abbatron.com/products/part/get/ppj_ibn_knob

At a glance, the type A knurled binding post from Abbatron looks closest to
the SX-42 part. The others would work if that one's too fat. It would have
to be insulated from the chassis, of course, but if I'm not mistaken, the
original antenna connectors are mounted on a little phenolic board. I should
order a couple myself. Two of the connectors on my set are half-stripped and
wobbly.

Regards,

Phil Nelson
Phil's Old Radios
http://antiqueradio.org/index.html