I these “claw” tools have gotten very inexpensive lately! I would still be wary of a “cheap” one with a vintage crystal but it sounds like you have the right tools on hand.
The edges of the crystal need to be compressed slightly to get it into the rehaut.
ou need to reduce the OD of the crystal, so it drops in and then release the claw. After the claw is off, you ensure it is fully seated, but only pressing down, without "starting" the crystal, you are likely to crack it.
These is a set-up plate the crystal goes into so that the claw grabs slightly above the bottom most edge of the crystal. That goes into the rehaut and then the tool is removed, and finally the crystal is pressed home.
Old Seamaster 300 is this way and I'm fairly certain all Omegas are this way (with plastic crystals). Speedmaster and others also have an internal tension ring where you will absolutely destroy the crystal if you try to simply press it straight in.
Please have a look at this thread:
Basic watchmaking tips - crystal fitting | Omega Forums
A press is not the correct tool for this style of crystal - as has been noted it needs to have the outside diameter compressed - a couple of tools for that are shown in the thread above. So this is absolutely correct:
However this needs some clarification:
Tension ring crystals do not get installed or removed by compressing the outside diameter of the crystal. They do in fact get pressed straight into the case using a press. Unless you are terribly misaligned the crystal to start with, or have the wrong size, it shouldn't destroy the crystal at all.
