You will have to eliminate your detectors ability to "telescope" and make "length adjustments" (I don't see this as a problem).
1. Measure your current detector's shaft length first. It is assumed the present adjustment is what you like. Measure from any location at the handle end to the center of the bolt hole at the coil. Write it down.

2. Cut your upper shaft with a hack saw to the length you like and deburr the end.

3. Slide your Coupler into place (with the holes horizontal).

4. Square your coil with the main handle and mark the two shafts with a marker where the 4 side holes are to be drilled (1/4" diameter).

5. Remover the Coupler.

6. Drill your upper and lower shaft with a 1/4" diameter drill

7. Bolt the Coupler in place with the supplied plastic 1/4-20 bolts.

The price for the unit with extra wing-nuts is $25 plus $3 shipping in the Continental USA

Not only will the freezing problem be solved, but you will now have a coupling that does not wobble. If you need to separate your lower shaft often for transport, wing nuts are supplied as an option to the hex nuts.

Regards,
Chuck