I cannot justify paying $200 for a laser aligner for my enlarger, yet I cannot justify not having one at all. To that end, I decided to build my own. I admit I was inspired by the chapter in Way Beyond Monochrome showing a homemade one, but I made mine a little differently. First I needed a laser pointer. Radio Shack has one for $30, but my father-in-law said he had an ultrasound measuring tape he has never even taken out of the box that had a laser pointer in it. We cracked it open and took out the diode. We tested the battery power needed to turn it on and found it needed 3v, so I looked around and found a Christmas tea light that used a 3v watch battery and had an on/off switch. Next I needed a body to put it in, so I looked around my shop and found a 2 1/2 inch diameter chunk of acetal plastic, so I used that. I machined the plastic to the right length and faced the surfaces on my mini lathe, then drilled a small hole for the laser to shine through. I used an end mill to make the hole bigger for the actual diode to fit in, then bored the hole bigger for the battery holder and switch. Finally, I drilled and tapped three holes around the sides to accept set screws to make it possible to adjust the laser to perfect perpendicularity to the base rather than screws on the bottom as Ralph's book describes. I used some rubber cement to adhere the front of the diode to the hole and provide a flexible pivot point that the set screws could work against. The entire project took me 3 hours and cost $1.49.