Chi, I rarely saw this issue in the older/original PT cases but it seems more prevalent in the newer ones. I prefer to machine the case, especially if I am making the ring as the next crystal replacement would then no need any special "fitting" to be done. I have chucked up crystals in the lathe and increased their ID accordingly with a boring bar but once I made the case holding fixture it takes me about the same amount of time to do the case as it does a crystal...
Oh, I think I've seen this on the Cartel cases as well which leads me to believe they both come off the same machinery...
Dizz, I don't know if it's because maybe Clark's are just brittle or if this would happen with any acrylic crystal... I kinda wish they would make Lexan crystals - practically unbreakable, and are a bit more compliant...
Just send it on and I'll take care of ya...
I'm glad I don't have to make the final decision since there are so many who really "fit the mold". Ubi, Hike, Chiman, LHOOQ, alligoat, the list goes on...
T, thanks, I'm humbled...
I thought I'd pop up some pics that better "explain" a problem with the later PT and Cartel vintage cases. It seems that in addition to the problem posed by the oversize compression ring/plastic spacer the OD (outside diameter) of the rehaut on newer cases is usually to large. If someone forces a new crystal, like a Clark, down over this oversize "feature" the result is quite often a cracked crystal. Remember, Plexiglas does not take too kindly to being stretched a great deal.
I received a PT 1665 from one of the Brethren for a new compression ring. The new Clark crystal had already been installed to the case so I was going to pop it out and discovered it wouldn't budge. I thought, "Uh-Oh..." I looked at everything under the 'glass and saw a pretty nasty crack with little vertical stress cracks all around the base.
I measured the ID (inside diameter) of the crystal:
And then measured the rehaut OD:
This resulted in an interference of about .0105 which is about .006" - .007" too much. I have seen a couple with about .013" interference...
There are two things that can be done. One approach is to machine the crystal ID to match up with the rehaut while another is to machine the rehaut OD to obtain a more reasonable fit - I prefer the later as it makes future crystal changes more of a DIY procedure.
A fixture I fabricated with the same diameter and thread pitch as the case back was mounted in the lathe and the case was then screwed onto the fixture:
After the case is snugged up onto the fixture it can then be spun and the rehaut OD turned to the proper size. I like to turn to about .002" interference which provides a nice "slip fit" but won't fall off under it's own weight.
With this little issue out of the way all that remains is to make a compression ring to fit.
This is hard! Hike is a fantastic person, but since he has already been nominated I toss Ubi's name into the hat. He continues to give selflessly to the community.
After much kicking and howling my GZ parts supplier has reluctantly agreed to pick up one of these for me. He said, "It's a cheap quartz fake, I can't guarantee quality..." I told him it was a small price to pay to satisfy my curiosity so he will pick it up after the New Years holiday, unless he changes his mind... I'll post up some pics if I ever get it...
You maybe could just gently heat it up with a hair-dryer until the glue softens and use your fingers to "rotate" the insert where it goes while the glue is soft...
When you change to the plexi you will probably need to shave don the ID of the bezel but I doubt it will be enough to thin it much. You might be able to make a slightly thinner bezel, though...