More polishing questions

[Joe L]

This post is the perfect example of how much you guys have learned and shared as a result of years of working with these pistols.   Thanks.

We don't know diddly about the striker guns yet.  At least I don't.  They aren't as elegant as the hammer guns, even the polymer ones, that's for sure.  The elegance in the late guns is in the manufacturing tolerances, not the design, seems to me.  I love the steel guns, even when not shooting them.  Hard to love the polymer guns until one shoots them.   

Joe

[briang2ad]

It could provide a smoother break yes, you would need to look at your trigger bar some of them can be rough and see if the bottom of the tab is hanging hang up there right before it slips off. Start removing material from the lower part of that tub tho does advance your DA timing so don't go crazy there.

But like what was said above you can always buy a new disco, factory ones are cheap but CGW ones are better.

Thank you sir.

On the first point - does an advance in DA timing also mean more over travel - OR does taking metal off the disco DECREASE over travel?

I do have a new disco (and trigger bar for that matter).  I don't mond investing in a CGW Disco - do these 'drop in' to a PreB usually? 

[ThompsonCustom]

It could provide a smoother break yes, you would need to look at your trigger bar some of them can be rough and see if the bottom of the tab is hanging hang up there right before it slips off. Start removing material from the lower part of that tub tho does advance your DA timing so don't go crazy there.

But like what was said above you can always buy a new disco, factory ones are cheap but CGW ones are better.

Thank you sir.

On the first point - does an advance in DA timing also mean more over travel - OR does taking metal off the disco DECREASE over travel?

I do have a new disco (and trigger bar for that matter).  I don't mond investing in a CGW Disco - do these 'drop in' to a PreB usually?

Well most of the time when I think of over travel I only think of the sa break point since it is behind the da break point but ya advancing the timing also increase the DA over travel since the hammer drops early in DA.

[sniperboy]

I am a bit late, but back on topic - I did find my DA of my SP-01 was stacking and it was driving me crazy.
I did have a CZC tuned Shadow as well and came to the assumption that the "nose" of the disco that rubs against the frame need not rub on the frame until the very end of the trigger pull.  My off the shelf SP-01 with Cajun Disco was rubbing a significant distance of the pull.

So I measured the length of the nose and started to remove material slowly from the tip with a flat stone - it was like half a hair, but it was enough to remove the stacking feeling.  My DA is still not as good as the CZC tuned Shadow but I just try not to think of it and maybe it will naturally get lighter after a few thousand rounds.  : )

Be WARNED, if you take off too much from the nose you may shorten it to a point where your DA hammer pull may NOT drop.  This is what happened to a Tanfoglio Stock 2 I had.  Though in that scenario my purpose was to extend the DA trigger pull, and purposely wanted to see how much material I could remove before I ruined the disco.

[Tok36]

I am a bit late, but back on topic - I did find my DA of my SP-01 was stacking and it was driving me crazy.
I did have a CZC tuned Shadow as well and came to the assumption that the "nose" of the disco that rubs against the frame need not rub on the frame until the very end of the trigger pull.  My off the shelf SP-01 with Cajun Disco was rubbing a significant distance of the pull.

So I measured the length of the nose and started to remove material slowly from the tip with a flat stone - it was like half a hair, but it was enough to remove the stacking feeling.  My DA is still not as good as the CZC tuned Shadow but I just try not to think of it and maybe it will naturally get lighter after a few thousand rounds.  : )

  You make an interesting point. I have not tested this specifically.

  If you take the slide off of a CZ pistol and place a small flashlight inside the opened dust cover facing the sear cage. Then look directly down the "muzzle" of the frame at the sear cage while assisting the hammer and working the trigger you can directly observe this happening. I was examining one of my CZs recently and noticed the disco only made contact with the frame towards the end of travel.

Interesting stuff.

[sniperboy]

Here is an interesting exercise you can do if you are curious like me. 
As Tok36 said, remove the slide, then observe the "nose" of the disco from the front. 
Take a piece of wax paper or thin paper.  You can cut a small sliver from the wax backing of a priority mail sticker.  Slip that in between the nose of the disco and the frame.

It is best to have a "control", that is, a frame that you know has a great DA pull and functions to your satisfaction.
While keeping that wax paper under the nose of your test subject, you can activate that hammer in DA - taking care not to let the hammer drop or protect it from hammering the frame.  While pulling the trigger slowly and tugging on the paper you can discern the moment it really "bites".

Since frame tolerances may not all be the same and disco designs differ, you can't simply measure the dimensions of the "working" disco.
Compare and contrast between both setups.

[briang2ad]

I think I can live with a slight drag on the tail end of the pull - I polished the bottom of the disco nose and the frame under the disco. 

What I'd like is MAYBE a bit more travel of the system and LESS overtravel.  My educated guess is that if I remove SOME of the steel from the rear of the trigger bar at the SLOPE of the rear where it engages the sear cage, I will decrease OT.  TRUE?  I figure if I remove too mush I risk not releasing the DA hammer. 

There is a P09 thread out there that basically shows this - much easier to do on a P series because there is more surface to deal with - this is very tiny on the 75 series. 

[ThompsonCustom]

Can you remove some of the over travel in the DA, Yes but not much.

The distance between the DA break point and the SA break point is all you can decrease which isn't much, go to far and your da pull will just put the gun in SA because when the trigger bar slips off the disco the hammer hooks will be caught by the sear.

So to get any real decrease in over travel you would have to move both the SA and DA break points backwards/retard the timing.

[briang2ad]

Can you remove some of the over travel in the DA, Yes but not much.

The distance between the DA break point and the SA break point is all you can decrease which isn't much, go to far and your da pull will just put the gun in SA because when the trigger bar slips off the disco the hammer hooks will be caught by the sear.

So to get any real decrease in over travel you would have to move both the SA and DA break points backwards/retard the timing.

So how does one do that?  Work on the rear slope of the trigger bar?  (That is the subject of the P09 thread I saw).

[DOC 1500]

 Brian do you have a link to that po9 thread ?

[briang2ad]

Doc:  I?ll look,

https://czfirearms.us/index.php?topic=70324.0

[DOC 1500]

Doc:  I?ll look,

https://czfirearms.us/index.php?topic=70324.0

Hey Brian, thanks for that info I never knew that existed. Good stuff

[briang2ad]

NP Doc - glad to help.

BTW - just tried the beveling of the discommector on my P07 that has similar issues with a hard break in DA. I think it works.  I MAY have to do more.  I lightly polished a bevel in the lead edge with a 900 carbide stone.  It seems a little smoother now.  I will do the same on my 88 PreB eventually.