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Skydiver

Tips for Fitting the Flat Trigger

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I pondered having a 17 and/or 18 produced as an option in case of difficulties like you mention. But my feeling is that it would be a compromise over trying to get all the other parts fitted nicely.

I'd buy one as I'd much prefer a more "positive" reset with my stock trigger.

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With the way the trigger bar sits on the plunger in my gun, I wish I could bore or counter-sink the hole on top of the plunger to the right size and depth, and drop in a ball bearing.

That actually sounds like a great idea and doesn't seem too technically difficult either. I'm no gunsmith but it does seems the plunger/trigger bar interface on these guns are the achilles heal of the trigger system...especially after the install of the flat trigger.

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I can definitely get a variety of springs made, that's not a problem. See, if everything is tuned and smooth, a lighter 16 may be possible as well. I can see it being cool to have 15, 16, 17 and 18 as options. But you know, don't forget that there are other springs out there in the world that may also work. I found a pencil spring that I originally used. It was super-light, but worked.

The spring length is 0.400" and the OD is 0.140". Spring length can probably vary from about 0.350 - 0.500 and OD from 0.130 - 0.145. So look around in your drawers for other types of springs that may work for this application as well.

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Very little trigger pretravel movement, clean break, tight fit. Over travel was very simple to adjust while trigger was in frame. Now when manually cocking the hammer (slide off) the trigger would reset 100% of the time. I also had zero hammer/sear interference when cocking the hammer with the trigger pulled back. When I decided all was set I put the slide back on the frame to give it a try. When manually racking the slide back the trigger would not reset at all. I would have to manually push the trigger toward the muzzle to reset it every time. When cocking the hammer manually with my thumb it WOULD reset 100%.

Sounds like you don't have enough pretravel. These guns require a bit more pretravel to reset properly - you can't dial it all out so that the trigger barely moves before you're pushing on the sear. Dial in a bunch more pretravel, then reassemble the gun. Squeeze the trigger and keep it pulled. Rack the slide. Slowly let the trigger out while listening. As soon as you hear the reset 'click', you'll notice you have to pull the trigger a bit before you contact the sear again. Once you know that point, you can dial out some of that pretravel, but leave a bit of 'wiggle' room just to be safe.

With the way the trigger bar sits on the plunger in my gun, I wish I could bore or counter-sink the hole on top of the plunger to the right size and depth, and drop in a ball bearing. Think of the tip of a ballpoint pen, or a roll-on dispenser, but the ball is free to pop out. The trigger bar itself would keep the ball bearing from popping out and in theory the only point of contact between the trigger bar and the ball will be a single point. If done right the ball will rotate freely inside the slot. Even if the ball didn't rotate freely in the plunger, a single point should be a lot less friction as compared to two almost similarly shaped curved surfaces rubbing against each other.

I wonder if a Telflon ball bearing would even be better than a steel ball bearing since Teflon has a lower coefficient of friction. Teflon against Teflon has even yet a lower coefficient of friction.

Hmmm... McMaster-Carr has Teflon balls, as well as Teflon tape with adhesive backs... Hmmm... Put tape in the channel under the trigger bar and the ball in an appropriately prepared plunger. May have to trim some coils on the plunger spring to compensate for the added thickness of the tape and exposed ball.

Any thoughts from engineering minded people about this setup?

Actually, less surface area between contacts will increase friction. Friction (or more appropriately 'Force due to friction') = Force / Area. More surface to bear the load will result in lower wear and less friction. Problem with the stock bar and plunger is that they are rough, and even after polishing, they still only contact in a very small area and are very hard to match the curve of the surfaces to each other and maintain that contact. The ball bearing would allow a nice hard low-wear surface, but it will probably eat the trigger bar alive - you'll have a track worn in in no time, along with a nice dent from the trigger bar bouncing up and down from reseting. The trigger bar's surface would have to be just as hard to prevent this, or a larger bearing surface implemented, like the roller plunger H is speaking of.

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Henning, why don't you just design a new CZ based gun from the ground up. Take the elements of the Tanfoglio you like best, plus whatever you've designed yourself, and just make a fresh new gun? Solid billet machined uppers and lowers etc. Man I'd be all over one. with todays machining, I bet you could come in at damn near the same price point, and then we'd have a truly top notch product that needs no upgrades, to shoot.

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Gundry - maybe your right on the too little pretravel. I took the gun to the range today for the first time and to my surprise the trigger never reset. While dry firing (both manually cocking hammer and racking slide) I had finally adjusted the trigger to 100% reset. The recoil/violence of live fire somehow made the trigger perform differently than my dry fire testing. I didnt bring my tools to the range so I wasnt able to adjust the trigger on site. I went through about 300rds having to push the trigger back into position after every shot lol...not fun. My advice on these new triggers is to adjust the trigger at the range as what you get at home by dry firing isnt the same as actually firing the pistol...at least it wasnt in my case. Im going to play with trigger at the range on my next visit and go from there. Henning is also sending me a stronger return spring so maybe that will help as well.

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Ran into similar issues today with failure to reset. Not a constant fail, about 10% fail. When I got home I was able to duplicate in dry fire. Seemed like the trigger was hanging up just a bit. Removed everything, readjusted the preset and it was better. Stretched the spring slightly and it seems to be fine now. Overall, really happy with the feel of this trigger though. Hitting the range on Wed to run it again.

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I installed the trigger today and it went pretty well. I think I did differently than most people though. I got the whole hammer/sear/pins/trigger package from Henning (ordered Wednesday night, day before thanksgiving, got the parts on Saturday!). I put the hammer/sear/pins in my Limited (got big hands and don't really want the flat trigger) and then put the Limited's old hammer, sear, and the flat trigger in my wife's regular Witness Steel.

I had to file down the front of the trigger bow quite a bit where the trigger pin goes through, it hit the inside of the trigger. The pin from the stock trigger doesn't really fit all that well (it's too long, and slightly too large diameter), but I think it's "good enough". Other than that and having to round off two corners on the new trigger rod nut to get it to fit, the install was uneventful. The reset on the trigger seems like it may be too light, I had one or two fails to reset during dry fire. Hopefully I'll get a chance to do live fire next weekend.

A suggestion for a possible future improvement: make the edges of the pretravel stop serrated, then we can tweak it minor amounts with a screwdriver or knife blade in the field and not have to disassemble things.

Oh, and *wow*, I love the EGW hammer/sear/henning hammer-sear pins combo. Light and crisp, very little overtravel and pretravel required.

I can't be the first person to have thought of this, but I use Henning's slave pin idea to reassemble the sear. The WD40 straw was too narrow and not strong enough so I cut myself off a piece of machine screw that I had laying around which was just a little smaller diameter than the pin. Make it as wide as the sear (just the sear, not the cage). Then you can insert everything and get that PITA sear spring where it belongs, then just push the real pin through and push out the slave pin.

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Darthmuffin> please report back after live fire. Thats were I ran into failure to resets even though it performed flawlessly in dryfire. I know theres a sweet spot in there somewhere.

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The "16" return spring (0.016" music wire) that I ended up going with is the lightest that I could make run in my test guns. It seems as it's still a border-line spring for 100% reset when to-date you take all the guns with my new trigger installed. As I've mentioned in previous post, I can get a "17" and/or "18" spring made and maybe this is necessary. The reports back are pretty much written in these posts. I haven't gotten any emails from shooters that haven't been able to get it to work after a little attention to the larger picture. I hate to supply a product that causes pain and suffering and grief. I try to tweak the design to it's potential and here's where we've got to make a choice. If we go with the heavier spring, no doubt we can make a 100% positive reset. That would be more in line with what factories does to make sure everything works all the time which is their primary concern at the expense of ultimate performance. My gun had the same reset issues described when I ran a "14" spring. Works on dry-fire, but not in actual shooting. The trigger bar and plunger and the bar's interaction with the sear is what needs to be looked at. I'm positive you all can get the "16" to reset if these parts are carefully looked at.

Next step...

I have some prototype trigger plunger springs which are slightly lighter. This helps take some of the pressure off the trigger bar. Lightens trigger / pull.

Rolling trigger plunger head and improved trigger plunger. George Huening used to make them and said he would start making them again. Not sure what the status is. It's been on my list of parts to improve, but the trigger was the first step. If this part is improved, we may even be able to get the "14" return spring to work.

Trigger bar.. oh yes... I have thoughts and ideas for it. In fact one of the parts we will look at today to see how hard it will be to manufacture.

Alternate springs.. I was able to make a spring from a [writing] pen to work. Look in your drawers and bins. Think outside the box. Springs with OD up to 0.150" or so will slip in there and maybe you can find something that'll work even better.

Custom over-travel screw. Charlie pointed out that a shafted over-travel screw would eliminate the potential friction and hang-up between the return spring and the OT screw. When I designed the trigger and it's parts, I initially thought of doing this, but opted for an off-the-shelf 3-48 set screw. Being that you could experience drag which will be felt in the trigger pull, maybe I'll have a special screw made. The trigger consist of a custom-made trigger, PT screw, TR spring, trigger pin, trigger nut and the OT screw. 5 custom parts had to be made and I "hated" just buying the OT screw, but hey... If you feel drag, you could grind the part of the screw that interacts with the return spring.

On the comment on the trigger bar roll pin... The hole is 0.098" and the pins are 0.100"+. The original trigger is roughly 0.325" wide if i remember correctly and my new one is 0.250" where the pin goes through. I suggest grinding off the extra portion of the existing pin. I made some attempts to source a reasonable roll pin in 0.250" width, but no luck. I will continue to look for one though. We can use the existing one which is why it's not high priority. It would just be nice to have a nicely fitted pin to slip right in.

Please keep posting comments and experiences. This is how we continue to improve. I am leaving for Norway tomorrow and gone for one week. Towards the end of the month we will start working on the adjustable trigger and any improvements that makes sense we will incorporate.

;-)

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Actually, less surface area between contacts will increase friction. Friction (or more appropriately 'Force due to friction') = Force / Area. More surface to bear the load will result in lower wear and less friction. Problem with the stock bar and plunger is that they are rough, and even after polishing, they still only contact in a very small area and are very hard to match the curve of the surfaces to each other and maintain that contact. The ball bearing would allow a nice hard low-wear surface, but it will probably eat the trigger bar alive - you'll have a track worn in in no time, along with a nice dent from the trigger bar bouncing up and down from reseting. The trigger bar's surface would have to be just as hard to prevent this, or a larger bearing surface implemented, like the roller plunger H is speaking of.

Good points! Thanks for the info.

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In the flat trigger installs that I have fiddled with so far 90% of the "Funky" reset issues are due to these three things. (1) Trigger bar to plunger friction (2) Return spring is hanging up on the threads of the over travel screw as it compresses, and (3) Too much lock tight is used on the pretravel screw and it gums up the trigger to trigger bar hinge point.

First and foremost you MUST optimize the interface between the trigger bar and the plunger head. Smooth these two points out and polish the crap out of them. The dremel is your friend in this area.

Secondly the trigger return spring can get bent out of whack pretty easy where the ends are bent at an angle and that promotes the middle of the spring to rub or catch on the threads of the over travel set screw. Make sure that the spring is straight as that is very important. I have also been thinking about using small wire heat shrink tubing to put on the threaded portion of the over travel screw that the spring rubs up against. The heat shrink tubing would smooth out the set screw’s threads and allow the spring to slide past them easier. Or at least I think it would. I still have to test theory out, but that was the best/easiest idea I could come up with for the current parts. As Henning mentioned a true solution would be for the set screw to only have threads on the top and be a solid shaft below where the spring would rub. That would eliminate any spring to set screw interference.

Third, watch out for using too much lock tight on the pre travel screw as the excess will end up coating the roll pin that connects the trigger bar to the trigger. This will gum up the movement between the two quite a bit and the .016 return spring may not be strong enough to overcome the extra friction between the two parts. Make sure that the trigger bar and trigger can freely flop around when the parts are outside the gun. If they don’t then you probably have too much lock tight gumming up the works.

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I also want to point out that when all of these parts are installed properly, you can make an absolutely SICK trigger pull. If you are not up to the task of optimizing these things, leave it to the guys that can. Nobody likes battling their gun when shooting it due to things not being installed properly. Get it done right once and be done with it.

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Just my OWN OPINION. The issue between the trigger bar and plunger.

First. Is this because the distance of the holes of the stock trigger and the new trigger different? I am guessing that the new trigger have more distance between the trigger bar pin hole and the trigger frame hole.

Can someone actually measure what the difference is? If they are the same distance then it's good. That's one problem solved.

Second. The distance of the trigger bar pin hole must be adjusted to the new over travel and trigger return spring while maintaining the distance on the trigger frame hole.

By the looks of the new trigger, there is enough space for the trigger bar pin hole to be moved around. In theory, if you get the right distances of the holes, the plunger/trigger bar will not be affected at all.

Like any product on the market, there are always bugs that need fixing. I had this experience when the first EGW hammer and sear went out 2 years ago. They have different angles against the stock hammer. I have broken a sear and 2 hammers until I got the 3rd one a perfect fit by grinding some angles.

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a lighter plunger spring seems to be an easy way to ease pressure on the plunger/trigger bar interface.

Henning> Do you have any of these available?

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jmleenz> You can achieve the same thing by cutting a coil off of the standard plunger spring.

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Chalee> I may try that. What are the negative side effects of making the plunger spring lighter?

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jmleenz> The main purpose of the plunger spring is to support the trigger bar upwards so it can engage the leg of the sear. If the plunger spring becomes too light you may get inconsistent resetting of the trigger bar against the sear leg. Also, if the sear leg is cut at a backwards angle, if there is not enough plunger spring tension the trigger bar will simply push down and slip off of the sear leg instead of pushing the sear leg back to trip the hammer.

The Plunger spring would have to be very light for these things to happen though. You can cut one coil off of the plunger spring and still have 100% reliable trigger function as long as everything else is setup correctly.

Once again, if you don't feel comfortable with working on it yourself just send it to someone that can do it.

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I finished fitting my new flat trigger this evening. I first ground the trigger bar pin to short, although it is nice that it doesn't stick out of either side of the trigger, so perhaps that minor mishap was a blessing in disguise. The Henning trigger pin initially would not pass through the frame holes, but a quick cleanup of the frame hole solved that issue. Once i finally got everything fitting into the frame, I encountered the reset issue mentioned by several others in the topic. I had already polished the sides of the trigger bar, as well as the top of the plunger. I noticed that although the trigger bar moved freely on the pin, the range of motion was limited by some interference with the head of the trigger bar in the slot on the back of the trigger. I removed the trigger bar and ground down the head a bit and that solved the issue.

The minimal amount of movement required to trip the sear and reset is nearly magical. The little bit of polishing I did to the trigger bar and the plunger lightened up my trigger about a half pound, and made it much more consistent. It is still a little heavy, breaking at a hair less than 5#. I am waiting for my EGW hammer and sear before messing with it any more - hopefully later this week. I'd like to get a consistent pull between 3# and 3.5#. This is my first Tanfoglio, and I must say I already like this trigger more than virtually all of my 1911/2011s

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I had access to .018 tempered stainless springs so I brought several home to try. After cutting to length and installing I found that in my application the trigger reset was much more positive. There seems to be only a slight increase in trigger pull and the reset is very crisp. I expect over time things will lighten up a bit so I think this will be the way I run. Henning may be correct, having and option in spring diameter may allow us to tune the trigger to our liking. My fingers are pretty long so I still plan to upgrade when the adjustable trigger is available but in the mean time I got rid of the curved trigger which I just hated. Still very satisfied with the ease of removal / install of the new trigger.

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jmleenz> The main purpose of the plunger spring is to support the trigger bar upwards so it can engage the leg of the sear. If the plunger spring becomes too light you may get inconsistent resetting of the trigger bar against the sear leg. Also, if the sear leg is cut at a backwards angle, if there is not enough plunger spring tension the trigger bar will simply push down and slip off of the sear leg instead of pushing the sear leg back to trip the hammer.

The Plunger spring would have to be very light for these things to happen though. You can cut one coil off of the plunger spring and still have 100% reliable trigger function as long as everything else is setup correctly.

Once again, if you don't feel comfortable with working on it yourself just send it to someone that can do it.

I wouldn't recommend going more than 2 coils. :-)

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Charlie has some very good points on the issues that can cause resistance. I've experienced the same and it is gun-to-gun related.

Give me some feedback here if you want it or not, but I can have several spring weights made:

0.015"

0.016" (this is the one supplied)

0.017"

0.018"

Give me a BIG YES if you want me to get these made. Personally I prefer a lot of choices, but I don't want to confuse the issue to much either as said previously a heavier spring masks the underlying problems.

I'm in Norway at the moment so I don't have access to my guns, but the pin hole locations are a direct match from the factory setup. If someone wants to give this a look... it is possible that changing the pin location could optimize the trigger even more. This is something I have not looked at, but it may be worth investigating.

Lighter trigger plunger spring... yes cut 1.5, may 2 coils off will lighten the pressure off the plunger and can help. As Charlie says, you can't take too much off. I have some samples made and I had a talk with my spring guy yesterday and I told him I want the sample springs made up. Those are roughly 25% lighter than the factory springs and they do help. I would want to use a lighter spring in junction with a roller head.

As for an over-travel screw, I WILL make a custom screw. With these trigger I had 4 machined parts made so it was overwhelming. Now that we've got the trigger working we can optimize with a slick OT screw without threads to rub on the return spring. I'll take a look at it when I'm back in Colorado next week. Charlie; what's your opinion on the screw's OAL ? I think my OT screw sticks out about 0.070" below the trigger. It needs to have enough threads to accomodate and adjustment. I'll have to look at how much of the threads can stick out on top without causing issues. Charlie, please look at it for me as well and I'll compare your notes to mine when I get home. I can make the non-threaded part either thinner or thicker than the threaded. If thicker to match the spring's ID it may help guide it better ? Thoughts ? Also, the bottom point of the OT set screw what shape it should be, round, flat, semi-round. Let me know, give input and I'll get it made.

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sinnsyk> I will look into the things you suggested. Off the top of my head I think that the OAL of the over travel screw could be longer. On the flat triggers that I have worked on so far they all have the allen head of the screw deep into the trigger well below the top of where it screws into. If you setup the flat trigger to be straight up and down at rest the length of the over travel screw isn’t going to vary much from one gun to the next. If you made the top portion of the over travel screw threaded and the bottom part a solid shaft just a bit smaller than the spring that would be best. That way the spring wouldn’t be compressed at an angle because the over travel screw shaft would keep the spring straight. It would probably be best to have the bottom of the over travel screw tapered to somewhat of a point. This way you would minimize the chance of the end of the screw trapping the spring between it and the frame. Since these pieces are collapsing at an angle you need some fudge room to account for this.

As for the spring, I think that the spring weight isn’t as much of an issue as the coil count of the springs. The current spring is a pretty low coil count and that promotes side to side movement when it is compressed. If the coil count could be increased you would get more consistent compression of the spring. It would also last longer at the same spring rate. You could also use a lighter spring (.015) that is longer and shim it as needed to preload it to your desired reset tension. You could easily put washers on the over travel screw that seat up into the cup where the spring rests. The only thing that you would have to worry about there is shimming it too much and it ends up coil binding before the over travel screw bottoms out on the frame. You could go fiddle crazy with this part.

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pin hole locations are a direct match from the factory setup. If someone wants to give this a look... it is possible that changing the pin location could optimize the trigger even more. This is something I have not looked at, but it may be worth investigating.

IF the pin hole locations are a direct match from the factory, then we have solved half of the problem already. All we need to do is measure/mark where the trigger bar pin hole sits in the frame. Let me explain...

Install the stock trigger and mark the trigger bar pin hole against the frame. Now install the new trigger and see the difference. I am confident that it will look like this.

HST201.JPG

The red circle marks where the stock trigger bar pin hole sits. This explains why the new trigger doesn't work with altered sear leg. It is being pulled away from the sear and if you notice, 0.04" is far enough to do this. The white line indicates that the distance of holes should still be the same.(stock and new) This will give the correct angle and height of the trigger bar. This will keep the sear, trigger bar and plunger perspective the same. As if we never changed the trigger! =)

This picture shows where the trigger bar pin hole should be moved... around +/- 0.08" difference. Remember, the white line indicates the factory holes distance. It should never be altered!

HST13c.jpg

Again, the best way to measure this is by marking the frame where the original hole sits. Install the new trigger and make sure the trigger has a 90degree angle against the frame/trigger guard. This is preferably done with the new trigger WITHOUT the trigger bar pin hole. Blank or no hole is easier to mark.

Once this is all done, I can guarantee that even a 14lbs trigger return spring will be sweet and still give a 100% positive reset.

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Made it to the range today and the new .018 spring I installed yesterday works great. Nice crisp reset with negligible difference in trigger weight. Because this spring has a couple of more coils and a bit stiffer in stainless the issue or friction with the set screw seems to be gone. The outside diameter of this spring is such that it just fits in the trigger cup ( doesn't want to fall out during install ) and the inner diameter is just a bit larger than the .016 spring. 1st pic compares the spring I installed with the .016" spring.

post-16185-1259808968_thumb.jpg

post-16185-1259808987_thumb.jpg

post-16185-1259809013_thumb.jpg

Edited by NoSteel

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