My first question here. I have a SB-9 lathe and have been using a drum switch for control: forward, reverse, off. I am in the process of re-installing it in my new garage shop and am finding that there is a problem with the drum switch being in danger of accidental activation by someone passing by. The garage is a common path to the vehicles so the entire family goes through there often. For some time I have also wanted to add Emergency Stop switch(es) for additional safety while working with it. So, I want to install a contactor with the appropriate On, Off, and E-Stop controls. I have noticed that the contactors most commonly come with either a 24 V or a 115 V coil. Now, I have worked with and even designed and built a lot of electronic equipment that has remote controls and, for the most part, those items would use a low Voltage for the control circuit: 24 V, 12 V, and more recently with the increased use of logic ICs, 5 V. These controls have always worked with little or no trouble and any problems were usually not due to the low Voltage being used. On the other hand, much machinery does use 115 Volts or an even higher Voltage for controls. So I am asking, is there anything different about mechanical machinery that makes the higher Voltage desirable or even necessary? Or is this just a hold-over from older use? I would prefer to use the 24 Volt control circuitry as it would be safer to run it to the E-Stop switches around the machine.