Claude,
This is a different animal to yours - it is only a touch sensor for finding the edge of a part. The probe 'ball' has a retaining spring pulling it upwards into the tubular lower shaft. This shaft is insulated by being mounted on a piece of paxolin. The ball spring is in series with the leds which are in series with the batteries and a resistor. When the ball contacts the workpiece the circuit is completed through the machine hence the leds light up - in the picture I've just crept up on the vice fixed jaw.
If I remember correctly there are three button cells of the lesser diameter than LR44 in a plastic tube - I wanted to keep the shaft diameter down to 1/2" so it could go into a normal chuck for setting up rather than have to mount a 20mm collet as per a commercial one that I have.
I believe I have only changed the batteries ONCE in the life of this beast, which as I said earlier is best part of twelve years.
Plans: good heavens there were no plans ! I made it up as I went along.
Andrew
This is a different animal to yours - it is only a touch sensor for finding the edge of a part. The probe 'ball' has a retaining spring pulling it upwards into the tubular lower shaft. This shaft is insulated by being mounted on a piece of paxolin. The ball spring is in series with the leds which are in series with the batteries and a resistor. When the ball contacts the workpiece the circuit is completed through the machine hence the leds light up - in the picture I've just crept up on the vice fixed jaw.
If I remember correctly there are three button cells of the lesser diameter than LR44 in a plastic tube - I wanted to keep the shaft diameter down to 1/2" so it could go into a normal chuck for setting up rather than have to mount a 20mm collet as per a commercial one that I have.
I believe I have only changed the batteries ONCE in the life of this beast, which as I said earlier is best part of twelve years.
Plans: good heavens there were no plans ! I made it up as I went along.
Andrew
Andrew Mawson, proud to be a member of MetalworkingFun Forum since Oct 2013.