How about this?

So one of those reasonably regular father son chats:
explains situation then asks do you have a *?
I've got *, will that do?
Text picture to help decide (one of the great things these modern phones were made for).
Agree the handover.
Hang up.
Remember that marvellous battery powered thing under the workbench.
More phone calls.
Now just have to do the handover then wait and see what works.
I like to think these types of phone calls are happening all over the world 24 hours a day.

Oh for the day it's a case of 'sorry once the laser is set to 2.4mm it could take all of three seconds to do it.'