I covered the lenses with low tack masking tape before work, hopefully preventing any scratches etc. Having heard horror stories about virtually anything attacking plexiglass, I did test the tape on a scrap piece prior to doing this!
I put a light behind the lens to help show up the aperture when tracing the outline on the masking tape.
Cutting the Plexi-Glass
The manual talks about positioning the lens to avoid “curl” as much as possible. Well there wasn’t much leeway as you can see from the picture, but actually the worst curl was right at the edges anyway.
I decided to try a Dremel Cutting Disc to trim the lens, using a Plastic Cutting Wheel.
This seemed to work well, cutting a short length at a time over several passes.
I think the general advice is to cut this stuff when nice and warm, but being Autumn here in the UK and in the middle of a cold snap, this wasn’t convenient. But after one pass with the disc, the area of the cut was as warm as a warm thing anyway!!
The lens has to be pushed up tight to the front to ensure a nice fit whilst match drilling. The manual suggests pulling it with tape wrapped around. Further advice in the manual says …
Luckily I’ve got one of those, so rather than use the tape, Coral came to the rescue and pressed the lens firmly to the front while I match drilled with a #30 Plexi-Bit.
It’s a good plan NOT to drill your other half’s fingers when doing this, so be careful!!!
In theory you need a #30 and #27 Plexi-Bit to get this job done. These sizes are really hard (impossible) to find in the UK, and I’d ordered some from a company in the US. When they didn’t turn up, I resorted to ordering a close 9/64″ from here in UK, but just after I’d ordered them the US ones arrived after all!!
The plexi-bits did a great job, taking it gently and slowly.
Deburring & Fitting
I used a sharp blade to smoooth the edges, finishing off with sandpaper.
After countersinking the lenses (carefully!), and attaching some double sided tape to the backing strips, they were ready to fit. Actually I don’t think you really need this tape, it’s pretty easy to hold the lens/backing piece assembly in place with a helper … Coral again.
I was pleased to get this little job done without any major dramas : ). Now I know they both fit OK, I’ll probably remove the lenses and keep them safe until later.
Anyway, that’s another section all finished. Onwards and upwards!!