A Tutorial for Detectorists: Mount a Wireless Transmitter to a Metal Detector, page 3

How to Affix a Junction Box with a Wireless Module to Your Non-Wireless Detector's Upper Shaft

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This setup works for metal detectors having the headphone sockets positioned both near the armrest (Configuration 1: an enclosed transmitter is mounted on the upper shaft) and on a control box (Configuration 2: the enclosed transmitter is mounted on the upper shaft or the middle shaft). If the shaft has no holes available for attaching the enclosure, drilling four holes in the shaft is required. If you would like to mount the enclosure with the wireless transmitter onto the armrest, either it is plastic or metal, drilling two holes in it will be necessary.

This tutorial mainly covers the process of setting the enclosed transmitter near the armrest (config. 1) of a Fisher F75+ metal detector, and includes pictures of the enclosed transmitter mounted near the control box (config. 2) of a Teknetics G2+ metal detector. Four holes were drilled in the Teknetics G2+'s upper shaft.

The Fisher F75+'s upper shaft conveniently has 12 holes for adjusting the armrest. The first thing to do is to position the junction box flat against the shaft's right side, as close to an armrest as possible, below an imaginary line of the armrest's "rest area" for your forearm, and a couple of inches above the floor when the detector (without a lower shaft and a search coil) is standing upright as shown on a picture below.

If you use a rain & dust cover for a battery compartment/box situated ander the armrest, make sure that there is enough space between the junction box and the battery compartment so that the rain & dust cover could be easily put on and off. A picture below shows a completed setup of the enclosed wireless transmitter on a Teknetics T2+ with the battery-compartment cover put on.

While holding the box firmly in its designated position against the detector's shaft, insert a small Phillips screwdriver into each designated hole in the shaft from the opposite side and rotate the screwdriver to mark a spot on a junction box where a hole for a bolt has to be made. Make sure that, with such positioning of the box, a connecting cable reaches the transmitter's micro USB socket with a good margin of length, and is not strained when connected to both the transmitter and the detector's 1/4-inch phone socket. Especially this should be factored in if your detector has a 1/8-inch (3.5mm) phone socket, and a 1/8-to-1/4-inch adapter also must be used.

In case you do not have holes available for mounting the enclosure on the detector's upper shaft or you need to mount the enclosure onto a middle shaft, you can drill holes of 4.8 mm in diameter where you need them. This is absolutely OK to do as the shaft can not be impaired by adding just four small holes to it.

NOTE 1: Before deciding where to drill four holes on this end of the upper shaft, where it accepts the middle shaft, mark a point to which the middle shaft extends when it is fully inserted and locked inside the upper shaft. The holes for attaching the enclosure should be at some distance away from that point.

Since the shaft has a curved surface, and a drill bit has a tendency to wander when you first start drilling, it is kind of hard to drill a Ø4.8mm hole where you want it on the shaft. The easiest way to do it is to create a small dimple at the designated spot for each hole on the shaft. As I did not have a center punch to do that, I simply used a drill bit of a smaller diameter (3mm) first in order to establish the holes exactly at the marked spots, and on the opposite side as I drilled the shaft with the Ø3mm drill-bit all the way through. Then I drilled successively larger holes.

NOTE 2: If you need to drill holes in the upper shaft's portion extending between the armrest and the handle, make sure you do it gradually not to damage two wires running inside the shaft - from a battery compartment (if there is one) to a control box.

After I drilled holes, I removed any sharp edges or burrs left behind by a rotary file. Another way to deburr holes is to use a drill bit slightly larger in diameter than the holes you just drilled, and gently hand-twist it over the top of each hole.

Next step is to make two holes in the plastic junction box. For this operation, you can use either the electric drill or a soldering-iron.

I used the soldering-iron because, with it, I could also flatten and smooth the surfaces around the holes where the washers must be placed under the bolt heads inside the box - this is important!

The smoothed surfaces allow for placing washers flush to the box's bottom; thus, providing the most contact area with it and, therefore, ensuring its maximum integrity, and motionlessness of the box mounted onto the shaft.

NOTE 3: While using the soldering-iron, be extremely cautious not to accidentally touch the box's cover housing and/or walls with a hot tip or body of the soldering-iron. If the cover housing gets a small deformity, the cover will not lock tight or may not lock at all. And if you accidentally make a tiny hole in the box's wall, any protection from water and dust ingress will be compromised.

After you put the bolts with washers through the holes in the box, and before you attach the box to the shaft, look through the holes in the shaft to make sure there is nothing in the way. If you see the internal wires blocking the holes, use a small screwdriver to push the wires out of the way. Then attach the box to the detector's shaft and check that the box is correctly positioned in all respects.

NOTE 4: For a good-noticeability purpose, the junction boxes are shown in their original light-gray color in the tutorial's pictures. If you would like your enclosure to be less visible, spray it with Black Matte Finish Spray Paint and let it dry before mounting the box onto your metal detector.

Secure the setup with as many nuts as needed to make sure the bolts' ends are not exposed too much to accidentally catch your clothes when you swing the detector too close to yourself.

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