I love the Beseler 45 enlarger design. It is well built and easily found on the used market. The design is unique as it uses two columns for support rather than the more common single column. It is designed to attach to a metal table called an Adjust-Table, and rises to a height of about 3 1/2 feet, allowing a 16″x20″ print. I regularly print up to 40″x50″ so clearly I needed to come up with a custom solution. One solution that Ansel Adams used, is to have the enlarger project horizontally rather than vertically. The main drawback with this is that it takes up a lot of space, and for small prints it is somewhat inconvenient to have to hang the printing paper on a vertical surface. I have tall ceilings so decided to stick with the vertical arrangement. What I needed was a taller Beseler; the idea of the franken-beseler was born.
The original Beseler frame is a custom bent U-channel. Inside the channel is a geared track on which a circular gear rides to move the carrier. I measured the inside dimension of the channel and was able to find something with a similar inside dimension. So from McMaster Carr I ordered 2 pieces of 6295K124 1/2″ by 6′ steel gear track and 2 pieces of 7779T22 steel U channel. I tapped the gear track and drilled holes in the channel every 10 inches to hold the two pieces together. I carefully adjusted the column separation and bolted them together. At that point the carrier could slide freely inside my new, taller chassis.
I knew from early measurements that the stock gear drive was not going to work with my new gear and channel. The original gear track that Beseler used is not very tall, so the gear that drives it is relatively large (see Figure 1). I looked at several suppliers for the same height gear track, but couldn’t find a supplier. So I knew I would need to get a new gear. This is where my 3-D printer shown in Figure 3 came in handy.
I fired up OpenSCAD and designed a gear that was the right size to drive along the track. The fixed variables were the height of the track, the pitch of the gear and the radius of the motor drive shaft. This let me determine the required radius of the gear. The printer prints parts using black ABS plastic which is fairly durable.
With my modifications I can extend my enlarger carrier 12 feet into the air, allowing me to print 40″x50″ prints from a 4×5 inch negative using my standard Nikon 135mm enlarging lens. A modification like this isn’t for everyone, but it demonstrates what I love about old designs like the Beseler. They allow for “tinkerability”!