ic-racer you really seem to have the touch. American ingenuity. Thanks.
Only one of my rollers rotted so I still have micro height adjustment - funny thing is i never use it though. I just raise and lower head by push/pull. But it always bothered me fishing for the rubber pices in bottom column.
I have had my D5500 for coming on 16 years. I placed a 6" flash opal glass on bottom of condenser assembly and turned it into a diffused source, replacing 75W bulb with 250W and at times 150W. Removed plastic fins and replaced with small computer fans to blow are past condenser head. Together with Ilford filters, makes better B&W prints than my Saunders 45 II dichroic