negative end connected in series between the positive node 100 and the negative node 102 are the four switches 104 the current limiting device 106 a resistor 110 and the indicator led 22 care should be taken that the negative end of the current limiting component 106 is connected toward the negative node 102 and that the indicating led 22 is connected according to its polarization since all four switches are connected in series when any of the contacts are broken the circuit is broken extinguishing the indicator led 22 as a visual indication that contact with the tool bit has been detected in a preferred embodiment diodes manufactured under the name siliconix j511 are used for the n channel jfets 108 and the resistor 110 has a value of 22 ohms this allows the tool eye setter to safely operate when 3 to 48 volts dc are applied between the positive node 100 and negative node 102 the tool eye setter as connected in the embodiments shown merely extinguishes a normally lit led when contact with a tool bit is connected it should be apparent to those skilled in the art how a microprocessor can be connected to the tool.