©Lin Yangchen


special part designation
bh2-ycfh

cad file download
personal non-commercial use only
use at your own risk


Constructive solid geometry in FreeCAD.
The mounting ring is thinner-walled than the Olympus design so it won’t cover the beautiful engraved field diaphragm symbols on the field lens housing on which it sits. The curved flap protruding upwards from the ring is a tray stop—not found on the Olympus version—to align the filters when they are swung in.

When installed on the microscope, the hinge for the filter trays will be at a compass bearing of 30° instead of the roughly 60° in Olympus' design. It will be easier to swing the filters out of the light path into the space behind, where they won't get in the way of your hands. Even when they are swung out this way, they are low enough to remain clear of the descending rack of the condenser focusing mechanism.

Olympus’ hinge design is rather complicated, with a pig-nose screw to hold the stack together and discourage people from dismantling it, plus tightening bolts for each tray. I went for a much simpler design of just a pin and matching holes. There is no need for screws since gravity keeps everything down, and no need for tighteners if the parts are machined accurately.


The thrill of seeing my invention sculpted in stainless steel.

The neutral density filters in their new home.
A perfect fit on the field lens housing. I left the edges angular and unrounded to accentuate the visual qualities of the stainless steel.