Lens hole cutter for foam insert. Stock 64mm hole for 50mm Nikon lens.

thingiverse

I opted to build my own hole cutter for foam inserts to tailor them perfectly around my lenses. It was crafted to begin in reverse gear to initiate the cut, then switch to forward gear to finalize the hole. This method proves simpler and neater than a carving knife, and more budget-friendly compared to purchasing a hole saw from the hardware store. The outer dimension measures 64mm. The pictured model lacks the top edge's sharpness as seen in the prototype, I thought this would provide an even smoother cut, also be cautious when drilling and start at a slow pace.