A blade may be stainless, but in a folding knife, there's still the frame and springs, bolsters or other parts that are not likely to be stainless. Got anything similar in your collection to try a magnet on, wrapped in leather or electrical tape to avoid marking the knife?
I agree on the hard drive maggies. I pried a pair loose from a trashed drive and attach one to the belt clip of my Falcon so it's always there. The other clings to a spare digging trowel, so it stays with our detecting flat that's always in the truck even if no detectors came along.
Nothing intrinsically wrong with extending the cable from coil to machine, may even work at beyond 10 feet! Plastic pipe is quite flexible though. Wooden dowels inserted in the pipe may help, or you could use metal electrical conduit for most of the length with the stock plastic stem down near the coil. Tie and/or wrap a thin poly rope to the coil, so in the event you lose grip or the pole fails, the whole arrangement with coil attached doesn't join your knife down there swimming with the fishes!
I thought about attaching a magnet to the elongated stem somehow, thus that it could be suspended above the coil high enough to be out of detecting range, but easy to drop down to coil depth to "snag" whatever iron you may have located. That avoids a separate recovery effort once the detector locates a magnetic object.
I don't hold out much hope for a detector retrieval, but it's an interesting idea to ponder.
-Ed
