Most if not all of the “fancy” plastic/acrylic crystals like you see on older tank style watches are meant to be ordered just a tad larger than the measured dimensions, so that you could “snap”them in for a snug fit without using cement. The cement just adds some protection against moisture/dirt. I work them in until I have just one corner left to go, and then very carefully push the last bit in with thumb pressure.
With a round one, you can use a press or a crystal lifting/placing tool that squeezes it enough to fit into the bezel ring easier.
Glass crystals are not much different, but you need to be very careful with how you place them…many times the bezel needs to be heated a bit in order to allow it to swell so that you can pop the crystal in place, and then when it cools it holds even tighter.
You can warm them ( just the bezel!!) with a hairdryer, warming oven on Low, hotplate, etc.
Experiment with one that you don’t mind damaging prior to working on one you want to keep !
I order them just 1 mm larger than measured.
You’ll find enough variable even then, that you may have to file it to shape a bit,..taking off rough edges from the mold, etc.
I use the manicurist type files ( the ones that come in different grits/colors ) on the acrylics, and a fine diamond file on glass.
You’ll find your own method as you go.
Oh,…and don’t forget to buy two crystals…you will hate yourself for waiting for one only to break it, and then have to re-order.
I buy from everyone
Crystalfits
G-S crystal
Jules Borel
Cas-Ker
Otto Frei
Ebay.
Whoever has the best price, right product.
Best,
Randy
