Do you have basic woodworking skills?
With a router, hand drill, and a narrow blade saw (we call them "coping saws" or "jig saws") you should be able to replicate your plate using 1/4" plywood or hardboard. (That's why we call them "Lensboards" over there)
Saw a disc having the same diameter as your existing plate. File & sand nice and round.
Drill a 1/4"hole in the center, then use the coping saw to cut out a hole slightly larger than your new lens.
So far, so good, ... but it's too thick ...
Here's where the router comes in...
Do you have a router table, or can you find a neighbor who is into woodworking?
Using a straight cutter, rout a thin, 1/4" wide lip around the perimeter of the lensboard (oops... "plate").
It will now fit into your enlarger.
Do the same around the inner hole.
The lip should be thin enough (about 3/32" -2mm-) to let your retaining ring engage the threads on the lens.
Give it a squirt of black paint & the job's done.
There are other ways, for example...
Laminate together several concentric discs of thin model makers plywood (visit your local hobby shop).
With a few primitive skills, you'll never have to buy another lensboard (oops... plate) again.
Don't fall into the trap of thinking: "if it isn't a legitimate commercial product, it has no place in photography".
Have fun.
Reinhold
ww.classicBWphoto.com
