After watching the Dan Gelbart video I ordered a couple of these. They are a bit big 12mm dia. but it will do. www.ebay.co.uk/itm/12mm-Red-Laser-Focusable-Head-Diode-Tube-650nm-5mW-Dot-or-Cross-Line-Module/313172020159 Im not sure if this has a built in resistor or if I need to limit current, but it appears ok on a 3v cr2016 battery. I will make a removable spindle mount for the lathe when drilling, and I was thinking the cordless chuck, would help keep holes straight if I make a printed reference to drill through.