pressfit nickel plated disk into ABS plastic

That is a poor design. Better to put the washer on the other side and pull through the plastic. If you can't do that then redo the mold so that the washer is embedded in the plastic. Alternative is to provide clips to hold the washer in place or at the least put ribs on to reduce the tension on the plastic piece. Don't forget that the washer probably has a punched edge which means that if you install one way, you get a better hold than the other way. That the plastic is crazing is indicative that it is breaking apart so that is a bad thing which allows the plastic to degrade a lot sooner than if it was a solid peice.

-- Bob May Losing weight is easy! If you ever want to lose weight, eat and drink less. Works evevery time it is tried!

There is an ultrasonic press for this kind of operation. A slightly undersize hole is bored into the plastic and the machine creates the ultrasonic vibrations to give just enough heat to soften the plastic to accept the insert.

If you can find a shop that has one of these machines, this would be a six pack kind of job, or perhaps you might be able to heat the disk in an alternate manor to accomplish the same thing.

It might also help to use a heat lamp to pre warm the plastic and have a fan at the ready to cool everything when you have got the thing pressed in.

You might also get better resistance to pull out if you cut some shallow groves into the edge of the disk. As the plastic cools it shrinks a little and this will provide a little better grip.

Another way would be to cut the recess in the plastic a little deeper and put a small shoulder on the outside of the disk. You could then use a heated tube to displace some of the plastic over the shoulder on the disk and then after it cools trim the plastic.

Good luck.