You are the first person, on a couple different gun forums to notice the mods. Thank you.
Yeah, I bought a Pre B CZ 85 last year and I really like it but it's a big on the long/large side for concealed carry. I've been wanting to do this for awhile.
I got the CZ 85 slide release (both sides) from CZ Custom. I think I got the ambidextrous safeties from them, too. I got the spur hammer from CZ USA.
I did a lot of measuring, re-measuring, comparing, complete tear downs, etc. prior to starting the job.
The same spring that holds the left side slide release in the frame holds the right side in, just like on a CZ 85.
The same spring that holds the left side safety in also holds the right side safety in, just like on a CZ 85.
You just have to drill the right sized holes in the right side of the frame and the right side of the sear block, to accommodate the right side controls.
Also takes a little bit of opening them up, slowly, with lots of fit tests, to get them just right, when you're doing it in the garage on a drill press. The holes have to be straight and true.
The right side of the frame does not have the little position lock for the right side safety, like the CZ 85 has. I reasoned (hopefully correctly) that 1911's don't have that either and ambidextrous safeties work fine on them. I bought a carbide burr to make the circular cut in the right side of the frame (not a hole, just a cut part of the way into the frame) for the tab on the right side safety to move in. Then I decided I'd just remove the tab and try it (once again influenced by 1911 ambidextrous safeties). The way the CZ safeties fit together inside is every bit as robust as the 1911 types. If I find, in the future, that I need that feature I can still order another right side safety (the tumbler style) and make that cut (with a suitable amount of measuring/marking prior to spinning the burr).
The biggest issue of this project, so far, was fitting the safety to the sear. That hammer has almost no full cock hooks at all (shallowest full cock notches I've seen on a CZ 75 hammer). That would not let the arm on the front of the sear move up high enough to clear the "bump" on the shaft of the left side safety to allow it to move into the SAFE position. I needed to make sure I didn't take off too much so I very slowly stoned the "bump" with regular stops to wipe it off and test fit it for function. I kept count. It took me 24 time of inserting the left side safety, trying it, pulling it out, stoning a little material off, cleaning it up and reinserting it for another function test before I finally got it right.
I really have only one more thing I want to do to it. I want to file/sand off the front of the trigger guard to make it look even more like a Pre B CZ pistol. Then I'll go ahead and drill a small indention in the right side of the frame for the red dot that shows the safety is in the FIRE position. Then I'll have to send it off to be cerakoted since I'll have removed the finish (along with some metal) on the front of the trigger guard.
It was fun (with some aggravation mixed in with it.
I did not touch anything in the pistol to a stone except the safety, while fitting it to the sear. The SA trigger pull is 3 lbs. but so crisp it feels like it's lighter than that. You can feel it stop, when the trigger pull has lifted the firing pin block up out of the way and it's about to release the hammer, then it drops the hammer without anymore movement that you can feel.
Just need to get it to the range now and fire it to see how it shoots and make sure it's gong to work correctly.
The safety will not go to SAFE when the hammer is down. The pistol will not fire with the safety in the SAFE position. With the safety in the SAFE position you can pull the trigger very hard several times, then move the safety to FIRE and the hammer does not drop to half cock. All of that seems to be working just fine.
I ordered an adjustable sear from CGW but didn't wait to put it in. I figured I could use it if the fitting of the safety to the original sear didn't work.
I love the feel/control features of the CZ 85 and now I have a CZ 75 Compact with those features. Thumb cocking that spur hammer reminds me of the 1911's, too.
Good eye for detail. Like I said, so far, you're the only one that notices the CZ 85 features.
I've got pictures of the frame/sear after I worked on them but before the pistol was assembled if you want me to post them here.