Omega D2 Enlarger Power Focuser & Lift
I have had this beast since I got back into darkroom photography in 1989. I stepped away from the darkroom and film photography around 2004 and recently got sucked back in during late 2023.
One thing I discovered is this unit aged well in storage and aside from a thorough dusting it was ready to go. I noticed that my shoulder issues now prevent me from reaching up to the focus knob while leaning down to view the magnifying focuser. SO the first thing needed is to add a power focus to the unit.
My forays into CNC conversions paid off and it winds up being a fairly simple process...
Selecting the mounting location was pretty much a done deal. Two conveniently located holes will be used. I really did not want to start drilling holes in the frame. The enlarger has a Zone VI Cold Light installed and removing the light head would be needed to prevent possible damage from vibrations.
The part will be 3D printed using PETG filament. The extra holes on the portion that bolts to the frame are access for tools to secure the two inside screws of the stepper motor. The two mounting holes are slotted for belt adjustment. Plans are to design so no tensioning pulley will be required.
The mounting holes are not slotted on this test part. This part was just to verify all the basic dimensions were correct. Not bad for a first try! The focuser shaft pulley shown is 60 tooth, I wound up using a 80 tooth pulley. Thus far all parts have been sourced from my junk box. Drawing shows the refined part in CAD. An infill of 60% will preclude the need for braces.
The drive components will be:
A knob was 3D printed to be bolted on the hub of the installed 80 tooth pulley. This replaces the stock knob to allow manual focusing.
Here's the Stepper Controller I elected to use. The unit is very programmable with lots of modes available. One of two modes will be used, Motor Moves only with the rotation of the knob and Motor moves only with the CW or C button being pushed. The speed of the motor is programmable so the sped of the focus can be fine tuned. The instructions can be found here.
Settings:
The 4 pin end of the supplied cable is cut off to connect to the Phoenix terminal block on the back of the control unit.
Prior to putting the unit into a case I needed to deal with the bright fluorescent display. There were two blobs of potting material in opposite corners holding the boards in place. Gotta love the designers, the blobs partially covered the top of two chips. The material can best be described as a 50/50 mix of Hot Glue and Marshmallow. A double layer of Dark Red Roscoe Cinegel did the trick.
Steps to make the filter. I measured the front faceplate and using Turbo CAD, I created a DXF template. I then taped a layer of Cinegel filter to a piece of cardboard. Two sheets of filter were required to reduce the light output to an acceptable level. The filters were a light press fit over the stems of the switches which did not interfere with the switch function.
After stacking the parts together I used some dental floss to keep it all together. The button caps and the dental floss kept everything together while inserting the stack of boards back into the housing. Once the unit was pressed back into the housing I cut the dental floss and pulled it out. The waxy nature of the string made removal easier.
In the dark, the display is not as blazingly bright as this picture would suggest. Unless you are using some really red sensitive paper, it it a non issue. I installed a power switch on the rear panel to make it easy to turn on and off. In operation the CW button raises the lens and CCW lowers. The knob allows adjustment to the motor's speed, even while the motor is in motion.
Power Lift
Based on my dealings with the power focus, it seems like a smart move to power the lift. Same basic hardware, the stepper is a NEMA 23 due to the need for more power. Both controllers will be placed in a single enclosure.
The drive components will be:
Components during setup and testing. Once again the 3D printer was put into service to print the motor mounting bracket. This one is far simpler.
NEMA 23 stepper installed on frame. Next step will be to remove the lift crank
I 3D printed an adjustment arm and tapped it for 10-32 and mounted the idler pulley. This installs on one of the stepper motor mounting bolts.
Do NOT expect to just loosen the setscrew and slide the crank off of the shaft, it WILL take a gear puller of some sort as the shaft is splined and the crank is pressed into place. The amount of force needed is evidenced by the pusher screw dimple in the end of the shaft.
I found that boring the pulley with a Letter O ( 0.3160") drill and reamer was the "sweet spot". It takes a firm, but not excessive, amount of force by hand to position the pulley on the splined portion of the shaft. The head can be raised without the setscrews tightened, a good sign. I have a 2 foot length of MXL belting that I use to check alignment and everything looks like it will fit spot on. I am going to wait for the belts to arrive in the morning before I secure the large pulley on the shaft. Middle image shows the installed belt.
I needed a manual knob and it had to be larger than the one for the focuser, so a new design was made.
The video shows movement when the controller is set to 100, this can be varied to suit one's needs.
It took a long time to find a suitable enclosure and it finally arrived! Middle image show projected layout of the front panel, with the rear shown at the right. SW1/2 are individual power switches for the controllers. The back of the enclosure will have a master power switch. The smaller round outline below the switch is the power input socket. A DA15 connector (show at the right) will be the detachable cord for the stepper control cables. A single cable will go up the back side of the enlarger frame and branch to the two stepper motors.
Due to the odd shape and the high cost of the enclosure I selected, I decided to laser cut a front panel and bolt it into place. A large opening cut in the cabinet is much easier than placing all the cutouts. All wired up and ready to go (RH) Se the section above for the installation of the red filters.
A long cord was made up using a DA15 connector on the enclosure end and the two stepper connectors on the other. While the smaller stepper had a connector socket, the larger stepper was supplied with pigtails. I used a Phoenix connector and used 3M foam tape to secure it to the stepper body.
Front face after machining the housing. Rear panel after machining and installing the hardware.
Finished control unit, tested and ready to go to work!
Height Scale
Many years ago I had riveted a 36" metal ruler to the vertical frame of the D2, and used this to document the height of the lens. I decided to make a nice pointer for it. I designed and 3D printed a block out of PETG to clamp to the cross rod. I then laser cut and etched some clear acrylic and filled the etched groove with paint. Using solvent weld I bonded the pointer to the rear block. If it were metal you would think Omega had this as an option.
Page about the Zone VI Cold Light