Need ideas for making COIN PROBE

I've made a couple I found that 3/16" brass is more sensitive than 5/16". Not as durable but does seem to work better. I use dead Walnut tree branches about 1" - 1 1/2" in diameter / cut'em to 3" - 4" long. Take off the outer layer of bark leaving in surface rough (over time of use it'll become smooth). I drill the handle to within 3/4" of the top of the handle, same diameter as the probe and then drive the brass shaft of the probe into the handle. The probe lengths range from 6" to 8".

I've tried soft steel stock (same diameter as the brass) and haven't noticed any difference in feel. My next "rainy day project" is to get some copper tubing and make a handle. I don't like the T handle design; a friend of mine does and says he can feel the probe striking the coin better. He made his using copper plumbing fittings soldered together.

I would like to find some 3/16" hardened metal (copper or brass) that would withstand prying in soil but not mar coins, if such a thing exists. So far I haven't found what I'm looking for.

I use a flat blade screwdriver 3/16" x 6 for fishing coins out where I can not dig. The brass probes don't have the strength typically to work well.

Made mine out of 1/4" brass rod, with an inline handle. The handle is one you would use for a file, and I seem to really feel the target pretty good. The tip is bullet shaped, or blunt as to not scrape the coin, but it does happen from time to time. Brass is going to be stronger, or stiffer than copper. Even hard drawn copper will bend easier than the brass rod. Steel is out for me. Too afraid I would damage the coin in the process of removing it. Keep in mind our soil here is soft(sandy) so prying isn't much of an issue.

Don't know if this is helpfull, but may be worth a try. I do not use one of these probes.

I used to build & rebuild fishing rods ( my own). Sensitivity in a rod is one of its key attributes no matter what size or type. A key component is the rod butt or handle. Some of the best rods use a cork grip. Cork will transmit the slightest vibration to the hands. Try modifying an old rod butt, or make a metal shanked handle wrapped in cork or cork diskes glued up to make a handle. There is also a newer material that is a foam called Hypalon, also used for fishing rod handles. This is better for larger saltwater gear where the size of the fish lets you know it's there. Hypalon is not nearly as sensitive.

I went to one of the second hand stores and bought a long fork used for barbequeing. Then cut the fork off and blunted the end. It works fairly well and hangs from my web belt on carribiner clip, always at the ready. The wooden handle is already there and the shaft is long enough that I can hold on to it with one hand for better feel.

Ya coulda gotten a shish kebob skewer and saved some time & money!!! Try turning down the handle and do a cork laminate. You will be surprised at the difference in sensitivity !!!!

No doubt about it. There is more ingenuity among detectorist than in all the rocket scientist in Cape Canaveral!!!! I guess its true that the mother of invention is necessity. After all Alexader Graham Bell had to have a way to let his mistress know he was going to be detained as quick as possible so she wouldn't go looking him!

I like to use drill rod because I can use a smaller diameter rod which is easier to push into the ground. I use the small copper fitting on the end of the rod to make the tip a little wider than the rod. It makes the rod slide easier up and down as I tap and feel the coin. The tips is solder which is soft to keep from scratching the coin. Rob

Thanks  eagle77, hoser, 1privateer and WThesing for the GREAT ideas !   

WThesing........I was an avid fisherman from age 8 to 49, at which time my brother Paul invited me to my
first gun show and I became totally engrossed in target rifles and handloading. Now I've added an equally
exiting hobby (you guessed it !)..........Metal Detecting !!!!!!!!!!!!   In all my years of fishing it never dawned
on me that cork was a factor adding to the sensitivity of the rod (just hadn't read or heard of this.) This is
an amazing piece of information !  Soooooo, think I'll try adding some cork discs/donuts to the metal rod for
an extra-sensitive handle on my homemade coin probe  :!: !!!

I've been wondering whether it would increase sensitivity to use a rod made of a high conductivity metal.
Looking at conductivity charts, silver is the bench mark with a rating of 100, followed on a declining scale
by coppers, aluminum, brass and carbon steel. This is just a basic arrangement and different alloy percentages might cause an alteration in this line-up, but I would think close enough for our purposes.

Another thought (haven't tried yet) would be to use soft copper tubing, which should be highly conductive,
and stiffen it by inserting a brass rod, keeping the inner rod back from the business end of the probe
so that the copper tubing could be formed over the end, sort of bullet-shaped. This could be done
by drilling a co-bore into the end of a short piece of low-carbon steel rod, to make a forming die. The tapered end of the drill should provide a reasonable bullet-shaped end to the copper tubing. (This would be
the reverse of flaring the end of soft copper tubing for an oil line connection.).
Of course, this suggestion is based on the assumption that a metal with good conductivity would provide
some additional sensitivity to vibrations created when the probe tip contacts metal in the ground. Also,
since I'm relatively new to MDing and have no experience using a probe, this whole idea may be superfluous.
I welcome anyones viewpoint on this hypothesis.........even if it's just   LOL !!

In closing, thanks to all for your replies !

Todd

Thanks Rob !   ...........Neat lookin probe and good pics too ! Looks like a ball-shaped handle. What
did you use ? Thats a great idea, using the copper sleeve and filling the end with soft solder (Lead) :!: !!

Just so there is no confusion, when referring to conductivity in metal, it is electrical conductivity. If you want to try something high tech, go to a hobby supplier that deals in R/C aircraft and get a carbon fibre rod. This stuff transmits vibration like no tomorrow. It will bend quite a bit before snapping, but if it does, it could cause injury to your hand.

It's a golf ball, the face is extra. Rob

If you are into filling the end with lead get some "leadless" solder at your local home center. This is Antimony which is harder than lead, but soft enough for your use. Auto wheel weights contain a fair amount of antimony with the lead. Silver solder is even harder.

rcasi44 said:

It's a golf ball, the face is extra. Rob

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Good idea Rob !.........The dimples provide some grip    !..........Thanks for the info.

Todd

I just use a cheap ice pick from Long's drugstore. $1.98.

WThesing said:

Just so there is no confusion, when referring to conductivity in metal, it is electrical conductivity. If you want to try something high tech, go to a hobby supplier that deals in R/C aircraft and get a carbon fibre rod. This stuff transmits vibration like no tomorrow. It will bend quite a bit before snapping, but if it does, it could cause injury to your hand.

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Thanks Bill, for the clarification on electrical conductivity, and tip on carbon fibre rod !

My interest in using a high conductivity metal for the probe rod was that it might help to transmit electromagnetic
impulses from a coin in the ground to the hand, when the probe tip makes contact. My conjecture is based on the
scientifically proven fact that every object in the known world emanates an electromagnetic energy field called "Aura".
I suspect that this Aura plays a part in the ability of certain individuals who can use metal rods to dowse for metals,
minerals ,etc., etc.. These individuals probably have a stronger Aura than the average person, but we all have some Aura.
This was merely a hunch on my part and I haven't really done any research. I do understand that voltage is
required to cause an electrical current to flow in a wire for example, but was hypothesizing that the
electromagnetic fields emanating from my hand and the coin in the ground might make a connection  !! 
To anyone highly educated in physics, etc. this is probably all laughable (Sorry...sometimes my imagination runs wild !)

HH to you Bill !

Todd

Rudy said:

I just use a cheap ice pick from Long's drugstore. $1.98.

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Rudy........Assume you blunted the tip  .........Thanks for responding !

Todd

Todd, I concurr with your statement. The problem lies with the RECEIVER end !!!!

ToddB64 said:

Rudy said:

I just use a cheap ice pick from Long's drugstore. $1.98.

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Rudy........Assume you blunted the tip  .........Thanks for responding !

Todd

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Of course. Another advantage is that continued use insures that it remains blunt.