Jump to content
Brian Enos's Forums... Maku mozo!

Sear help on Stock 3


AlphaSeeker

Recommended Posts

After full polish and spring work on my stock 3, I am left with two items that need correction.

1: during slow DA pull, a distinct step if felt as the hammer is pushed back and the first hammer lands engage the sear. Is there a means to minimize this.

2: if anyone has a diagram describing function of sear surfaces, this would be very helpful, the Stock 3 has a two piece sear mechanism.

I have a CGW 3 disco on the way and will try to minimize SA per travel .

Link to comment
Share on other sites

  • Replies 193
  • Created
  • Last Reply

In case anyone is interested, I mated the 9mm long slide from my Match to the Stock 3 frame. Works great. Unlike the glock mags, 9mm rounds do not hold in the tanfoglio 40 mags.

I will measure the barrels in the next day or two, to see if the 9 mm can be used in the 40 slide, with the proper extractor.

FYI, eaa has the tiny mag release detente for about $15 - one guess as to why I know this.

Link to comment
Share on other sites

I had some initial contact on the first hammer hooks like you described in #1. It was fixed by backing out the overtravel screw in the trigger a little bit.

The 2 piece sear has 4 engagement surfaces I am aware of. The hammer engagement is the obvious one at the back. If you are looking down at the sear with the muzzle pointed away from you, the right leg controls the firing pin block during firing and the left leg engages the safety.

There is a bottom leg underneath the safety leg which controls either reset or takeup. Can't remember.

Link to comment
Share on other sites

After full polish and spring work on my stock 3, I am left with two items that need correction.

1: during slow DA pull, a distinct step if felt as the hammer is pushed back and the first hammer lands engage the sear. Is there a means to minimize this.

Are you sure this is the correct diagnosis? Is this 1/2 way though the trigger pull, at the end, or where?

Link to comment
Share on other sites

I have a CGW 3 disco on the way and will try to minimize SA per travel .

thats interesting i didnt know that the CGW CZ disco can fit the Tanfo i thought it had a diff profile head

pls let us know how it works out.. Thanks

Link to comment
Share on other sites

I have a CGW 3 disco on the way and will try to minimize SA per travel .

thats interesting i didnt know that the CGW CZ disco can fit the Tanfo i thought it had a diff profile head

pls let us know how it works out.. Thanks

cpa5oh has installed a couple of them and I think kneelingatlas has also. I haven't got to mine yet.. :)

Link to comment
Share on other sites

The CGW T3 is oversized to allow fitting. I believe the pivot hole will have to be enlarged.

As for the "step", it occurs approximately 1/2 way into the DA trigger pull. I figure the first set of hammer hooks are engaging at this point.

The goal is to wind up with a smooth DA and a very tight SA, similar to the CZ custom shadow with the Short Reset interrupter.

Any steps in achieving this are appreciated.

Link to comment
Share on other sites

As for the "step", it occurs approximately 1/2 way into the DA trigger pull. I figure the first set of hammer hooks are engaging at this point.

I don't think that is what is happening. Most likely its the trigger bar starting to ramp down on the 2 downward protrusions off the sear cage. This eventually pushes the trigger bar off the disconnector and causes the hammer to drop. Or its the disconnector disconnecting from the trigger bar. Hard to tell from your description. Have you polished the underside of the sear cage and/or the faces that mate on the trigger bar and disconnector?

Link to comment
Share on other sites

I did not hit the Sear cage but the trigger bow/bar and disco are now mirror shiny and smooth. I did notice that the horns on the Bow were angular instead of a smooth radius. I think I need to revisit these parts and stone the radius for a smooth transition.

Thanks

Link to comment
Share on other sites

I've got the CGW disconnector (gunsmith fit) in one of my Stock 2's (the .40...just got the 9 so I haven't done anything with it yet - parts are on the way.) Since I've only worked on the one gun I can't say anything for sure...once I duplicate results on the 9 I'll feel more confident in what I'm about to say.

Below is what I did to make the disconnector work with a 1 piece sear (not the 2 piece sear that comes in the Stock 2):

- The pin hole needs to be reamed out - I used diamond bits that I got from Harbor Freight...the metal is hard as hell so it took some serious doing with the dremel and it ate a few of the bits. If you can get it to 3/32" you'll be in good shape.

- Once I had the disconnector in the gun, the trigger wouldn't break on the DA pull...the hammer disengaged from the sear but wouldn't fall because the disconnector was still hung up on the trigger bar (the two didn't disconnect.) I very slightly stoned a break in the lower front edge of the disconnector and that resolved that issue...be very careful, though, because if you break that edge too much the trigger bar won't stay on the disconnector enough to actually pull the hammer back - it just slips right off the disconnector - and you'll have wasted a disconnector (I've done it.)

- Those two things are all that I had to do to get the CGW disconnector to work (once I'd destroyed three figuring out what was happening.) A couple of notes... First, I think using the CGW disconnector eliminated the "stacking" feeling at the end of the DA trigger pull. It still stacks a little bit compared to the CZ Shadow I've got, but nowhere near to the degree that the 9mm (which was worked on by a respectable gunsmith, though not one known for Tanfoglio triggers) - with that gun, it's almost like you have no ability to tell when the hammer is going to drop...it's like it gets stuck for a split second and then drops. I think eliminating the stacking is a combination of going from 2 wings on the disconnector (on the stock disconnector) to 1 wing on the disconnector (the CGW part.) Second, I still have pre-travel in SA mode. I don't have that huge forward swing that some SA/DA triggers have (like a CZ without the SRT disconnector,) and the trigger stops going forward at the instant that the trigger bar pops up once it clears the lower left sear leg...but then from that point to the trigger break there's still about 3/16" of pre-travel. I think that's because the lower sear leg is angled like this / (bottom being farther forward than the rear) ...so the trigger bar has to come forward to clear the tip of the sear leg but then, when it's in it's highest position, is not flush with the sear leg and has to travel rearward before it engages the sear leg again. I need to play with shapes of the sear leg to try and eliminate that...which will require me to have a handful of sears...I think that angle on the sear leg is there to prevent the trigger bar from slipping off the sear leg before it actually pushes against it enough to rotate the sear.

The first time I tried to install a CGW disconnector I was using the 2 piece sear that came in the gun, which was a mess. If you've got the muzzle pointed away from you and you look down, the left piece of the sear actually has two bottom legs - a long one on the left and a shorter one on the right. Because the CGW disconnector has a "wing" that is flush at the top of the disconnector, that short right sear leg runs right smack into wing and the trigger doesn't function...I had to grind the wing of the disconnector down until there was enough clearance for that right leg to clear the wing.

Link to comment
Share on other sites

Thank you CPA. You've done a lot of work and I am grateful for the advice. Grainger sells carbide drill bits and I picked one up (3/32 =2.5mm) for $17. This should leave a finished surface and proper diameter. I figured that I would reduce the thickness of the wing by grinding the bottom flat - thank you for pointing me to the top surface as well. The part arrived yesterday - will post once I get into it.

Link to comment
Share on other sites

My pleasure...Nealio and kneelingatlas are the reasons I was able to take Tanfoglio triggers on myself.

Careful grinding on the bottom of the wing - I think that's the part that contacts the trigger bar...and like I said in my post, when I broke that edge too much the trigger bar and disconnector wouldn't stay connected and therefore the hammer would not go back (and the disconnector was ruined) - I think taking material off of the bottom of the wing would have the same effect as me breaking that lower leading edge too much.

Link to comment
Share on other sites

I've got the CGW disconnector (gunsmith fit) in one of my Stock 2's (the .40...just got the 9 so I haven't done anything with it yet - parts are on the way.) Since I've only worked on the one gun I can't say anything for sure...once I duplicate results on the 9 I'll feel more confident in what I'm about to say.

Below is what I did to make the disconnector work with a 1 piece sear (not the 2 piece sear that comes in the Stock 2):

- The pin hole needs to be reamed out - I used diamond bits that I got from Harbor Freight...the metal is hard as hell so it took some serious doing with the dremel and it ate a few of the bits. If you can get it to 3/32" you'll be in good shape.

- Once I had the disconnector in the gun, the trigger wouldn't break on the DA pull...the hammer disengaged from the sear but wouldn't fall because the disconnector was still hung up on the trigger bar (the two didn't disconnect.) I very slightly stoned a break in the lower front edge of the disconnector and that resolved that issue...be very careful, though, because if you break that edge too much the trigger bar won't stay on the disconnector enough to actually pull the hammer back - it just slips right off the disconnector - and you'll have wasted a disconnector (I've done it.)

- Those two things are all that I had to do to get the CGW disconnector to work (once I'd destroyed three figuring out what was happening.) A couple of notes... First, I think using the CGW disconnector eliminated the "stacking" feeling at the end of the DA trigger pull. It still stacks a little bit compared to the CZ Shadow I've got, but nowhere near to the degree that the 9mm (which was worked on by a respectable gunsmith, though not one known for Tanfoglio triggers) - with that gun, it's almost like you have no ability to tell when the hammer is going to drop...it's like it gets stuck for a split second and then drops. I think eliminating the stacking is a combination of going from 2 wings on the disconnector (on the stock disconnector) to 1 wing on the disconnector (the CGW part.) Second, I still have pre-travel in SA mode. I don't have that huge forward swing that some SA/DA triggers have (like a CZ without the SRT disconnector,) and the trigger stops going forward at the instant that the trigger bar pops up once it clears the lower left sear leg...but then from that point to the trigger break there's still about 3/16" of pre-travel. I think that's because the lower sear leg is angled like this / (bottom being farther forward than the rear) ...so the trigger bar has to come forward to clear the tip of the sear leg but then, when it's in it's highest position, is not flush with the sear leg and has to travel rearward before it engages the sear leg again. I need to play with shapes of the sear leg to try and eliminate that...which will require me to have a handful of sears...I think that angle on the sear leg is there to prevent the trigger bar from slipping off the sear leg before it actually pushes against it enough to rotate the sear.

The first time I tried to install a CGW disconnector I was using the 2 piece sear that came in the gun, which was a mess. If you've got the muzzle pointed away from you and you look down, the left piece of the sear actually has two bottom legs - a long one on the left and a shorter one on the right. Because the CGW disconnector has a "wing" that is flush at the top of the disconnector, that short right sear leg runs right smack into wing and the trigger doesn't function...I had to grind the wing of the disconnector down until there was enough clearance for that right leg to clear the wing.

I have one of CGW sitting around and trying to figure out how to make it work in my s2,

thanks for sharing.

Link to comment
Share on other sites

Got the CGW sear and began surgery. I used a round diamond file to gradually open up the pivot hole to 0.105(same as oem).

As forewarned by Cpa5oh, I thinned the wing from the top to allow the sear to rotate.

Test reassembly showed significant improvement in DA motion. Current problem is that the hammer does not fall in SA. The trigger does not reset when the hammer is positioned in SA. Any thoughts are appreciated. DA works fine in dry fire testing.

Link to comment
Share on other sites

Ok. Got everything working. For those seeking to minimize pre- travel in the Stock 3, I highly recommend the CGW t3 disco. I made some pics and a vid showing the SA result- will post soon.

The SA reset issues I had were caused by the FPB section in the sear mechanism. The Stock 3 has a two part sear, as pointed out by cpa5oh.

As the slide cycles, the trigger bow is pushed down and momentarily disengages from the disco. This leaves the hammer fully cocked. My trigger was not re-engaging the disco, thus unable to move the sear and stuck in the SA position . The fpb leg of the sear was preventing the bow from rising thus not allowing engagement with the other leg of the sear. Some stoning of the front of the front of the leg corrected the situation.

I now have almost no take up in SA. The hammer hooks and corresponding sear face are untouched except for a bevel at the top of the hooks. I should be able to eliminate most of the creep by reducing the height of the hammer hooks and stoning the underside of the sear to reduce the area if engagement. As is, the difference in the trigger is very significant.

Link to comment
Share on other sites

AlphaSeeker,

Can you summarize which CGW sear you used and what work was done to fit it and improve your trigger? I am assuming the Stock 2, 3, and Limited Pro have the same trigger mechanism. I have a Lim Pro and wouldn't mind trying my hand at improving the stock trigger's characteristics. Currently I know to polish various bits, change out springs, fit a different hammer, possibly stone that hammer's hooks, but the sear & disco are a mystery to me. I need to keep the gun Production legal so no nice EGW parts for me :(

I was under the impression that the stock Tanfoglio sear should not be stoned due to only surface hardening, which you will go through if you stone it. Then in a few hundred rounds your sear will be messed up due to the soft metal being deformed. Is this incorrect?

Link to comment
Share on other sites

The sear is original Tanfo [2 piece]. The disconnector is CGW T3 [oversized]. Wirk performed:

1: open pivot hole to 0.105" - used a round diamond file from Harbour Freight. Best $8 spent for shaping hardened steel. Carbide bits a re a waste of money unless you have a milling machine or a good drill press,

2:reduce length of vertical hook to allow clearance with frame

3: reduce thickness of wing [mostly from the top, to allow clearance for Firing Pin Block portion of the sear to rotate.

4: reduce thickness of wing from the bottom to allow disengagement from trigger bow while reducing the clearance requirement between bottom of sear/cage and top of disco.

5: stone engagement surface on the front of the "wing" to allow trigger bow to re-engage disco and sear in SA.

6: stone the front of the FPB leg of the sear to allow trigger bow to return to SA engagement after slide cycles.

The pictures show the difference in wing dimensions of the oem disco vs CGW.

My vid shows the creep still in my trigger. This will be addressed by reducing the height of the hammer hooks.

If I was certain that Tanfo sears are fully hardened, I would thin down the sear as well, to reduce the length of motion needed to disengage the hammer.

post-53024-0-59649500-1398703993_thumb.j

post-53024-0-00675800-1398704012_thumb.j

post-53024-0-24638900-1398704031_thumb.j

post-53024-0-50536700-1398704070_thumb.j

post-53024-0-01669700-1398705084_thumb.j

Link to comment
Share on other sites

Nice post alphaseeker! I have a couple of questions:

- how did you clearance the "wing" from the top (to make room for the baby leg of the left side piece of the sear?) I'm asking what tool you used, basically.

- do you think the trigger bar pushes against the disconnector in single action mode? I thought that the trigger bar and disconnector only connected on the DA pull...that the trigger bar pushed on the bottom legs of the sear only for a single action shot. Certainly I could be wrong because I've never actually been able to see what happens under that sear cage.

- do you think the "creep" you're feeling has anything to do with the fact that the sear is two pieces and the firing pin block arm of the sear rotates before the rest of the sear?

Link to comment
Share on other sites

A Dremel with a grinding stone did the rough work on the top surface of the wing. A flat diamond file then sharpened up the corner radius left by the dremel. A dressing stone made the surface prettier after the file.

Front edge of the wing was done on a fine grit India stone.

You are correct about SA TB engagement. If you did not have the disco, the sear would be tripped by the TB. In the DA design, the disco gets in the way. The length of sear legs and thickness of the disco wing is almost the same. When the slide cycles, the TB is pushed down and out of engagement with the disco. Unfortunately, it is also out of alignment with the sear legs at this point.

The trigger plunger spring pushes the TB to regain alignment with the sear legs - this is where the front surface of the disco wing and the FPB leg of the sear were interfering.

Th creep or travel of the trigger before the break is definitely due to long engagement surface between the sear and hammer. I can see the sear moving as the trigger is going through its motion. This is not a big problem since the pull is very uniform due to polishing.

I will wait to break the gun in for a few hundred rounds before removing more surface area from hammer hooks.

Similar results may be achieved by building up the oem disco. Will have to play with that once I find out what material it's made from - looks like a casting.

Link to comment
Share on other sites

  • 2 weeks later...

Archived

This topic is now archived and is closed to further replies.


×
×
  • Create New...