has anyone tried these VCC 10mm lenses (http://au.element14.com/vcc-visual-communications-company/hmc461rtp/led-lenses/dp/1700089) for mounting something like a silonex NSL-4532 (LDR)? that VCC part # HMC461-CTP is the clear. description says 15mm outside diameter and 10mm inside diameter so I'm thinking it should be a success despite the $1.26 price on mouser. also in the datasheet it says it includes the lock washer and nut.
detailed drawing of the HMC461
http://vcclite.com/_pdf/panel_lens/HMC-461-10mm-fresnel-thread-lens-drawing.pdf
Are you talking about on the exterior of the box for a photo eye expression pedal type build?
http://www.deviever.com/fx/peep/
thanks for the link. someone sent me an eye-of-god they wanted me to install into a bigger dual pedal but I decided to leave the eye-of-god as is and just clone it. its so simple. I clicked the diy info for that peep you linked. 517-SJ-5312CL is the part devi uses for the lens. its clear but then it fades over time to look like a molded lump of hot melt glue. I actually thought it was hot glue till you showed me that. anyway, good to know but I still like the VCC lens.