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Henning Shop Flat Trigger System

The flat trigger system trigger is a result of almost 20 years of shooting Tanfoglio pistols and extensive prototyping to develop a higher quality trigger.
Tanfoglio Pistols Flat Triggers

Introducing the Henning Flat Trigger System

The idea of developing a Precision Machined, straight surface trigger has been brewing for a few years. The need for a better single action trigger exist within most Tanfoglio enthusiasts. Is it absolutely necessary to replace the factory trigger ? It is not, but we have come to realize there are several issues that we want to eliminate in our guns. What makes this new trigger so much better ?

1) Precise Fit to Frame
If you inspect how the factory trigger fits in the frame you'll see how much sideways wobble there is. You may not think this is all that important, but how would you feel if I told you it was partially the reason why I ended up with a bullet hole in my foot ten years ago ? The frame is equipped with a "trigger guard" which main purpose is to protect the trigger from accidentally being pushed. Well, if the trigger is allowed to move outside the width of the trigger guard, it is exposed which is not a good thing from a safety perspective. Secondly, sideways wobble and slop prevents a precise trigger movement. The new Henning trigger is designed with a "boss" width of .335" which will allow for a tight fit inside the frame. The actual width of the lever that you pull with your finger is .250".

2) New Trigger Spring System
The factory trigger uses a two legged coil spring which can be very difficult to re-assemble. I always use a slave pin with the factory trigger spring on assembly. But it doesn't always work and it is still difficult to re-install the trigger if it has been taken out of the frame. So, this was one of the key issues I wanted to address when designing it. The Henning trigger uses a short, coiled spring similar to the Tanfoglio extractor spring. Instead of having a spring held in place by the trigger pin, it is now held in place by a spring pocket. This allows you to easily put the trigger back into the gun while pushing the trigger pin through the frame and locking the trigger in place.

3) Consistent Pre-Travel Adjustment
With the factory trigger, this is one of the major problems. Because of the set screw's positioning, the pre-travel is very difficult to adjust. We completely re-thought pre-travel adjustment and came up with a solution using a big headed screw that has a large surface to interface with the frame. Since we are working with a pivoting trigger, the pre-travel screw will meet the frame at different angles. Using a large headed screw eliminates this problem completely and we can finally adjust the pre-travel very exact.

4) Straight Trigger Surface
The factory curved single action trigger naturally wants your finger to be positioned at the center of the trigger. Well.. that may or may not be where you want to pull it. Having a straight trigger surface allows your finger the same trigger feel no matter where your fingers meets the trigger.

5) Clean Design and Innovative Design
One of the things I wanted to achieve was a modern, no bullshit looking trigger. We are pulling a lever and that's it. So let's make all edges smooth and comfortable.

6) Re-location of the over-travel adjustment screw
The factory's over-travel screw meets with the frame in a position where the frame is curved. This can cause an inconsistent end-of-travel point. I moved the over-travel into the frame where the screw meets a flat surface. It makes the trigger look clean.

There is a lot of attention to detail in this trigger as you will soon discover when you get your own. As usual, we spend a lot of time tinkering before we decide on a design. This trigger is a result of many hours on the drawing board and in the machine shop. I have a great machinist who is willing to work with me into the late morning hours. We spent a lot of time on this project and you can both see and feel the result.

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Selecting the right materials for the job.

Some think that you can use aluminum for a pivoting
style trigger. I say they are trying to cut corners
without truly respecting the wear pins can have over
year of usage. We went with 416 Stainless Steel
and heat treated it to Rockwell 37.

You can see the Pre-Travel Screw sticking out.
It is made from 303 Stainless and made to fit
very - very tight in the trigger. I need to use
blue loctite or Vibra-Tite VC3 to keep it in place
and be able to adjust. The last thing you want is
is for the screw to move.

The solid Trigger Pin & Nut are both made from
416 Stainless and heat treated to Rockwell 41.

Why a solid trigger pin over coiled roll pin ?

The problem with roll pin is that they can be compressed
to a much smaller dimensional hole, but as soon as
they are through the hole, will grow back to original
diameter. This means you would have to use a very
inaccurate hole in the trigger to reliably rotate
the trigger on the pin. The Trigger Pin is 0.005"
smaller diameter than the trigger pin hole.

Adjusting Over-Travel

As you can see, the over-travel is adjusted inside the
frame using a 0.050" allen hex key. You can use
the same bondhus screwdriver I use for my basepads.

Adjusting Pre-Travel

The new Pre-Travel screw has a large surface
interface with frame. You need to take the trigger out
of the frame to adjust and adhere it with loctite.

The Importance of Springs

Tuning the factory trigger bar where the plunger head and the bar meets is important for a smooth trigger feel and easy trigger reset. Adjusting springs help. We offer a variety of trigger plunger springs to tune to perfect. And you can select between 4 trigger return springs for optimal reset tension and tune the trigger pull weight to your liking.

For more on springs, check out the Henning Springs section.

Trigger Return Springs



Trigger pull weight is foremost depending on the trigger return spring. We offer four springs from #15 - #18. This means they are 0.015", 0.016", 0.017" and 0.018" in wire diameter. The difference is about 2 ounce (50 grams) effective trigger pull weight.

Trigger Plunger Springs



Secondly, the trigger plunger spring will affect both the trigger pull weight and the trigger reset. By reducing the pressure from the trigger plunger head onto the trigger bar, the lighter spring you can use or a trigger return spring. It's all connected as they say.. We offer 5 different springs, from #18 - #22. They affect the trigger pull weight by about one ounce (25 grams) each..

 

Three Triggers to choose from

Short Trigger (left): The original short trigger perfectly suited for shooters with smaller hands and / or shorter fingers. Glove size 8 and smaller.

Mid Trigger (middle): The new norm as of January 2011. Recommended for most shooters. 0.200" (5 mm) longer than the short trigger. Glove size 9-10.

Long Trigger (right): For the chosen few. I would say, for those who uses glove size 11 and above. You know who you are. It's about 0.235" (6 mm) longer than the mid-length trigger. We can't make it any longer and you probably don't want it any longer.. Our slickest design..

Videos of the new trigger:

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