Author Topic: CGW SRS-2/1485 DIY Trigger Job, Limited Edition Suppressor-ready Urban Grey  (Read 1481 times)

Online PappaWheelie

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  • "This is war, and in war, time is of the essence"
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Having already documented the conception-to-birth waiting period of 1 year, 1 month, 26 days and the surprise “handoff” from being Wifey’s Ultimate Bedroom Gun to mine,
http://www.czforum.com/forum/index.php?topic=5271.0
http://www.czfirearms.us/index.php?topic=97214.msg752634#msg752634
-and having documented CGW-based Short Reset System trigger job “How-To” in some (perhaps too much) detail,
http://www.czforum.com/forum/index.php?topic=5463.msg23034#msg23034
-this writeup will be a supplement/addendum to this “Easy-Peasy (Step-By-Step) DIY Short Reset Trigger Job” rather than a complete rewrite.

For quick reference, here are the device-specific parts diagram and parts list.
Parts_Diagram_CZ_75_SP-01_Tactical:
https://drive.google.com/open?id=12Ieu72QZycDr2pvzRXHryR8UfN9efIKc
List_of_Parts_CZ_75_SP-01_Tactical:
https://drive.google.com/open?id=1FvuEucG9Hgfr9ydOtZFBN4LHboHKcNHY
-And list of needed CGW parts: the $72 SRS-2 Short Reset System, the $38 1485-T2 Disconnector, the $13 TR-PIN Floating Trigger Pin, the $35 5 Thick Trigger, and the $7 RP-TRS Reduced Power Trigger Return Spring.

The first difference from the prior “Easy-Peasy…” writeup is the ambidextrous decocker of the SP-01 Tactical with its additional (#66) Hammer Decocking Lever Controller – Right, which has a spring-loaded release blade sandwiched into its lower/rear edge. To avoid any scuffing of the finish of this pristine, off-new-tooling gem of a pistol I used a plastic pusher blade cut from (nylon?) packaging strapping for the (New Step 8.5?) removal of said #66 Lever.  Tool:
https://drive.google.com/open?id=1UFvMJmFgpa8-P4A4iulLxGmvUm96Z_sp

For Step 10 Sear Pin removal, the risk of “billiard ball bounce” of Sear Pin ahead and away from the dummy sear cage pin (which may require tack hammer urging; said separation risking loss of piloting function) can be prevented by the thumb on your third hand if you’re built that way, but a fat rubber band can serve the same purpose for those of us with only two hands. 
Rubber_Band_Trick:
https://drive.google.com/open?id=1SQloZlv3Cy1699vhThszeV3V1tu1Jf4E

I ended up removing and reinstalling the sear cage several times in process of getting the Disconnector reset clearance dialed in, by the way, more on this later, and came to see that with this particular frame, at least, simply pushing the sear cage dummy pin against one’s work board while pushing/wiggling “downward” on the sear and decocker springs to overcome their upward bias (preload) in their assembly-energized state was all that was needed to enable easy push-fit assembly and disassembly.  If the dummy pin and sear cage holes aren’t aligned (due to the action of this hairpin spring bias), no amount of whacking with the tack hammer will suffice to progress the pin on through the sear cage wall.

Steps 19 - 22 “trigger job” work entails cleanup as needed on the (vertical) pusher faces of the (#7) Trigger Bar and the Single Action (SA) tooth of the (#16) Hammer.  The Trigger_Bar_Pusher_Faces:
https://drive.google.com/open?id=1Gp5pnN7QD9cJf5ivdBwR-XUy4p7RpZuY
were the “least perfect” textures of all of the interactive surfaces of this near-perfect specimen of a production CZ pistol. I fabricated a Trigger_Bar_Polishing_Tool:
https://drive.google.com/open?id=19-ifsFYHdkAbma6QhZtx9LLpmc0dPTg3
from a box cutter blade to enable getting up into the mill-sculpted boundaries of the pusher faces, pretty much a cosmetic pride issue, but having functional benefit of keeping the “roll” attitude (in aircraft pitch-yaw-roll terminology) preserved by the tool’s spanning of both surfaces together. The pitch attitude control was a bit more difficult due to the longitudinal flexibility of the blade: given another trigger job to do I’d make a polishing tool from thicker stock so that control of the free end elevation of the tool would assure maintenance of parallelism to the original surface, assuming the Hammer Bar being fixed in space by, for instance, a machinist’s vise.
Trigger_Bar_Pusher_Faces_After:
https://drive.google.com/open?id=1Oo6uazCrGoNsy5r-dOWnksgFnZlI8fPy

The Sear_Face:
https://drive.google.com/open?id=1oG2vREQWk60jj6G_iKZ4kkPpQZT_Znfu
was so pristine that attempts to “polish” it with 2000 grit wet-or-dry (again backed by a small box cutter blade narrowed to suit) only roughened it up!  Almost the same was encountered with the hammer’s SA tooth face, although I did manage to increase its “gloss level” a bit.  Hammer_Tooth_Before:
https://drive.google.com/open?id=1OCOX6csa881mKZJcwBiGHNiFMzu5AfYB
Hammer_Tooth_After:
https://drive.google.com/open?id=1kqn7izAvYLaoxse7tTjhh98zNCVbtPO-

I've referenced my massive Czech-built York vise in an earlier post...
http://www.czforum.com/forum/index.php?topic=5506.msg23220#msg23220
…I used it to hold the (#20) Main Spring Strut for the 2mm elevation of the (#21) Main Spring load face(s) for the proven-reliable preload reduction I’ve repeatedly enjoyed from my first trigger job. 
http://www.czforum.com/forum/index.php?topic=4798.msg20513#msg20513
York_150_Strut:
https://drive.google.com/open?id=1PAapjgRPLNbEAYWKdIB_3sRQzGfaFQ2L
York_150_Strut_Closeup: (look closely and you can read YORK 150 stamped on the moveable jaw)
https://drive.google.com/open?id=15VponDTesF4AF8mjWmm8tBhXMoobjg11
Half_Step:
https://drive.google.com/open?id=18Ml9PM3uyWhJ95dIZ0cmm3TGVvZlANZp
51mm_Was_49mm:
https://drive.google.com/open?id=17GVlsJKYIDyhMBrSl6X9rl5w73EmxgHi

My first trigger jobs with CGW’s SRS-2 Kit involved Main Springs with “Closed and Ground” ends, which maintain purely axial loading on compression springs.  This more recently-purchased (~1 year, 2 months ago) CGW SRS-2 Kit had closed but not ground Main Spring ends for an evident internal cost savings.  CGW_Recent_Main_Spring_End:
https://drive.google.com/open?id=1bSaz01kWnjrcdn5lqdnC6mERui61pYPq
Having the ability to remedy this demerit, I did so, gripping the spring ends with padded pliers and lightly dusting the last coil to “square” on the side of a bench grinder’s grinding wheel gradually enough to not cause loss of temper.
Main_Spring_End_Grind:
https://drive.google.com/open?id=1OIzc-wm5yKjTe6Yv4Zofwmc4-LKR53zF

While swapping out the firing pin and spring I noted that CGW’s (#59) Firing Pin Block Stop Spring was a comfortable clearance fit to its hole in (#58) Firing Pin Block Stop unlike the case with my CZ 97BD: http://www.czforum.com/forum/index.php?topic=5057.msg21330#msg21330
-so I used it for the incremental reduction in trigger pull forces it offers. I surmise that the evidently new tooling used for these Limited Edition Urban Grey Suppressor-ready SP-01 Tactical CZ 75’s produced a slightly larger spring bore than that of my 97, which may have incorporated a (#58) Block having been produced with worn spring bore tooling.  (  :o[ )

When assembled, it was obvious that the failure to reset that we had encountered with PeachBoy’s SP-01 Tactical http://www.czforum.com/forum/index.php?topic=5570.msg23308#msg23308
-and which CGW characterizes as affecting only ~10% of builds- was being upstaged “Bigly” (DJT) by my new gem, which no amount of pressure, finger or otherwise, would force to reset with the 1485-T2 Disco installed. Again reviewing options for interference elimination, I again opted to touch up the pristine “knife edge” at the bottom of the trigger bar’s disconnector notch rather than 1.) Spoil the “perfect” geometry and shiny texture of the CGW Disco itself; 2.) redo the now-polished pusher faces of the trigger bar; or 3.) mess with the deliberately “sharp corner” geometry of the sear foot that the pusher face engages, which serves to maintain the contact radius on this lever arm at always-maximum values. 

The hammer bar’s disco notch is 4mm wide so to radius the (harder than the hubs of Hell) knife edge properly would require wet-or-dry backed by a face width just under that 4mm. I found a parting tool amongst some old lathe tooling that would work with just a bit of hollow grinding (of its tapered cross section) to get its narrower edge down to 3.9mm. Rock-sawing the tool/wet-or-dry across the knife edge as symmetrically as I could, produced just enough of a corner radius to gain functional reset at the first trial reassembly.  Were I to do this again, or repeatedly (Hint, CGW), I’d make the 3.9mm touch-up tool into a T-section with a top having just a bit of clearance on the inner span of the trigger bar to maintain squareness (parallelism, actually, at the working surface) between tool and trigger bar.

The Short Reset System Kit itself doesn’t really change the reset distance: it takes the 1485-T2 Disco to do that; with the Disco installed, the Forward-most Single Action Trigger Position (FMSATP) is relocated rearward to just a hair before Single Action hammer motion begins.
FMSATP:
https://drive.google.com/open?id=1JyGCL01LHXv-SDMS_tCGcoz5ICG-Kq9v

Trigger pull values were assessed more accurately than those of previous posts by means of averaging the peak values of ten slow pull videos taken by my cellphone being held in the cellphone holder that PeachBoy son gave me for Christmas (to enable iTarget imaging http://www.czforum.com/forum/index.php?topic=5438.0) to document, real-time, my Rapala digital fish scale with “C-link” adapters for both mid-trigger (with nylon tube roller) and trigger tip (per http://www.czforum.com/forum/index.php?topic=5057.msg21330#msg21330 next-to-last paragraph). The values represent modest reductions as compared with PeachBoy son’s SP-01 Tactical job, where we had skipped, based on my CZ97BD job, the replacement of his firing pin block spring, and where reassembly didn’t include daubs of Anti-Seize on the (difficult to access after assembly) pusher faces of the trigger bar.

Mid-Trigger, After
PappaWheelie                        PeachBoy
   DA 7.36             84% of         8.73
   SA 3.10             83% of         3.74

Trigger Tip, After
PappaWheelie                        PeachBoy
   DA 5.21              98% of         5.30
   SA 2.41              89% of         2.71

The healthy DA values attest to not having gone overboard (in terms of defensive reliability) on the mainspring and mainspring strut mods. The SA values don’t communicate how absolutely linear and silky the thing feels.  Ultimate Bedroom Gun is now Crown Jewel.

I’m leaning towards the Surefire 9 Ti https://www.tactical-life.com/gear/surefire-sf-ryder-9-ti-suppressor/  as suppressor choice: the 1-1/4” OD field is pretty thin. Suggestions/experience in this diameter range welcomed.
« Last Edit: July 07, 2018, 10:06:58 AM by PappaWheelie »
Member, Gun Owners of America
CC: CZ 2075 RAMI BD in PappaWheelie Invisible 15 Round RAMI Holster
Homeboy: CZ 97 BD, Underwood 45 Super 120 Grain Xtreme Defender ammo
UBG: CZ 75 SP-01 Tactical Urban Grey Suppressor-ready
-all w/ CGW Short Reset Kit/1485-T2 Disco, 5 "Thick" Trigger, polished SA tooth

Online PappaWheelie

  • Full Member
  • ***
  • Posts: 127
  • "This is war, and in war, time is of the essence"
    • The Children's Bread
Member, Gun Owners of America
CC: CZ 2075 RAMI BD in PappaWheelie Invisible 15 Round RAMI Holster
Homeboy: CZ 97 BD, Underwood 45 Super 120 Grain Xtreme Defender ammo
UBG: CZ 75 SP-01 Tactical Urban Grey Suppressor-ready
-all w/ CGW Short Reset Kit/1485-T2 Disco, 5 "Thick" Trigger, polished SA tooth

Online PappaWheelie

  • Full Member
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  • Posts: 127
  • "This is war, and in war, time is of the essence"
    • The Children's Bread
The hammer bar’s disco notch is 4mm wide so to radius the (harder than the hubs of Hell) knife edge properly would require wet-or-dry backed by a face width just under that 4mm. I found a parting tool amongst some old lathe tooling that would work with just a bit of hollow grinding (of its tapered cross section) to get its narrower edge down to 3.9mm. Rock-sawing the tool/wet-or-dry across the knife edge as symmetrically as I could, produced just enough of a corner radius to gain functional reset at the first trial reassembly.  Were I to do this again, or repeatedly (Hint, CGW), I’d make the 3.9mm touch-up tool into a T-section with a top having just a bit of clearance on the inner span of the trigger bar to maintain squareness (parallelism, actually, at the working surface) between tool and trigger bar.
As it turned out on my first trip to the range since the above (I know, shame shame for the time lapse), trigger reset was intermittently unreliable, i.e., the hammer bar notch's V-edge needed to be rounded a bit more to reduce the "rearwardness" of the trigger bar and its working faces with respect to the sear foot, as pulled by the Disco/Hammer assembly. So I had opportunity to improve the working edge's geometry via actually making the above T-section modification to the 3.9mm wet-or-dry backing tool.
https://drive.google.com/open?id=1GJc7MN9Y-aG90xqQFJ8iJ7CTJvbB5BRQ
I fine-tuned the width of a wooden guide "stick" on the side face of a bench grinder's wheel, then superglued it to the hollow-ground parting tool used for backing up 600-grit wet-or-dry such that it couldn't "rock" (or roll, in roll-pitch-yaw aircraft terminology) under use. The result was an improvement in geometry that accompanied the decrease in hammer bar rearwardness.
« Last Edit: March 21, 2019, 11:53:15 AM by PappaWheelie »
Member, Gun Owners of America
CC: CZ 2075 RAMI BD in PappaWheelie Invisible 15 Round RAMI Holster
Homeboy: CZ 97 BD, Underwood 45 Super 120 Grain Xtreme Defender ammo
UBG: CZ 75 SP-01 Tactical Urban Grey Suppressor-ready
-all w/ CGW Short Reset Kit/1485-T2 Disco, 5 "Thick" Trigger, polished SA tooth

Online PappaWheelie

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  • "This is war, and in war, time is of the essence"
    • The Children's Bread
The result was an improvement in geometry that accompanied the decrease in hammer bar rearwardness.

A couple of magazines of live fire have confirmed that the above little tweak (increase of radius to the trigger bar notch's V-edge that the Disco pulls) fully fixed the problem, which had manifested immediately (1st shot and many thereafter) with the prior extent of sear foot clearance. Manual cycling didn't manifest the issue, it took live fire to show it.
What a sweet piece!!!
Member, Gun Owners of America
CC: CZ 2075 RAMI BD in PappaWheelie Invisible 15 Round RAMI Holster
Homeboy: CZ 97 BD, Underwood 45 Super 120 Grain Xtreme Defender ammo
UBG: CZ 75 SP-01 Tactical Urban Grey Suppressor-ready
-all w/ CGW Short Reset Kit/1485-T2 Disco, 5 "Thick" Trigger, polished SA tooth