Browse Categories
Shopping Cart
Your cart is empty.

Northwood Trigger Installation Guide

Kel-Tec P-11
Kel-Tec P-40

NOTE:  Please review this guide completely BEFORE purchasing your upgrade kit!

Kit Contents:

Trigger (ATP11T or ATP11A)*
Note: Trigger may still have faint tooling patterns from the machining process. Remove with light buffing.

  • Trigger Pin, Stainless (photo shows older-style, modified factory trigger pin)
  • Set Screw 6-32 x 3/16”, Stainless, Pre-installed with blue 242 Loctite
  • 2mm Pin Punch
  • 3mm Pin Punch
  • 1/16” Allen Hex Key

After 4/17/18, all triggers come with a setscrew pre-installed with blue LocTite.
The setscrew simply needs to be tightened 1/2 turn after the trigger is installed.
If it is hard to turn, warm the tip of the provided allen hex key with a match, insert into the setscrew,
hold 5 seconds, and try turning again.


                                                                 PLEASE BE SAFE!!

Make sure your firearm is unloaded. Follow all safety guidelines in your owner’s manual.

NOTE:  Once installed, the trigger may still need proper fitting for your firearm to function.
The trigger contact surfaces or grip cutout may need to be filed or sanded to obtain
the proper clearances required

Tools and Items Needed: 

Standard gun cleaning materials and lubes

Small hammer

Gun mat or soft working surface

Small wood blocks (2) same size

1/8” Pin Punch (available at hardware store)

Toothpicks and Q-Tips

Flat Blade Screwdriver (medium with long shank)

“Bic” Pen or short ¼” wood dowel

Round files, small and medium

Sandpaper, medium to fine grit

*  P-11 specific steps will use P-11 photos. Otherwise, PF-9 is used for illustration.


IMPORTANT: Inspect the gun carefully, while performing these steps.
Replace any worn or cracked components before attempting this installation.

Start by field stripping the pistol. You will be working only with the grip/frame assembly.
Once the slide assembly and magazine are set aside, begin with the frame removal.


Support the pistol on its side between two blocks of wood, books, or on a cartridge rack, and with a 1/8” pin punch and small hammer, tap out the three frame pins, as shown. (If your frame pins look larger on one side, tap them out from the smaller side.)

With the pistol in one hand, hold rearward pressure on the hammer with your finger while slowly pulling the trigger. Once hammer is released, allow it to rotate fully forward.



Page 2

The hammer spring retainer can be pushed out of its slot with a large screwdriver inserted through the top end of the magazine well, and into the recessed hole in the retainer.


Push up on the retainer until it clears the grip, and “rock” it toward you with your thumb. Let it down gently into the magazine well, while twisting it sideways slightly with the screwdriver.


Using the slide as a lever, gently begin lifting the front of the frame out of the grip until the trigger components are visible on the sides of the frame. Do not lift the frame out of the grip just yet.


Remove the slide from the frame, and set aside.


CAREFUL! There are components on both sides of the frame that will fly away unless you hold your fingers along the sides as you pull upward.



IDEA: Remove the frame from the grip with both hands inside a gallon size zip-lock bag to catch parts if they come loose.



Page 3


As you pull the frame clear from the grip, the hammer spring and retainer will come with it, and will dangle from the frame. Leave them attached for now. Keep holding the left and right frame components to the frame as you remove it from the grip. The trigger bar on the right side is spring loaded.


Set the grip assembly aside.



Turning the frame over…


While holding the trigger bar on the right side, turn the frame over. The left side components are the slide stop lever and spring. The spring sits on a nub in a circular cutout with the lower end riding in a very thin slot on top of the slide stop lever.


While still holding pressure on the right side (trigger bar), carefully release the slide stop lever and spring – and lift them away from the frame.


Set the slide stop lever and spring aside for now.



Page 4


Turn the frame assembly over to the right side.


Note the trigger spring “tab” positioned in the trigger bar slot. While holding down the front end of the trigger bar, carefully lift the larger end slightly, away from the hammer axis (pin).


Rotate the trigger bar clockwise, allowing the trigger spring to unwind out of the slot in the bottom of the trigger bar.



The trigger spring will not fly away, but it may sting your finger if it slips out of its groove prematurely.


Set the trigger bar aside.


Page 5


Trigger Removal

Place the frame across two blocks, allowing the hammer spring/retainer and the trigger to dangle


Look down at the top of the frame with the trigger fully forward in the reset position.
You will see the top of the trigger pin aligned with the small access hole in the top of the frame.


Notice the angle of the pin in relation to the frame.
Using the 2mm small punch provided, position it through the hole in the frame.
Position onto the trigger pin at the same angle as the pin.
Steady the frame as you hold the punch
in position.
CAREFULLY tap the pin until it pushes
out the bottom of the plastic trigger. Save this pin.
Your trigger may come out with the pin if it was cracked at the top, prior to this procedure.
A replacement trigger should be ordered from Kel-Tec as a spare.

*A 3/32” drift punch (shown) can be used, but the 2mm will penetrate the trigger more easily.


NOTE: The newer P-11 uses a “barbed” trigger pin (instead of the older straight one), and it might be extremely difficult to remove. CAUTION – Do not tap too hard on a stubborn pin that won’t budge. You can easily damage your trigger axis, or more importantly, your aluminum frame! Kel-Tec has said that the plastic trigger on newer guns may need to be “snipped out.”

Using a pair of diagonal pliers, snip away the plastic trigger from around the pin. Then grab the head with a pair of pliers, gave the pin a slight twist and pull it out gently.

If you are not comfortable doing this, seek help from a qualified gunsmith.


Remove the trigger spring from the right side of the trigger axis, and set aside. 

Page 6


Gently push out the trigger axis from the left side of the frame with the punch, and set aside.

 The stock trigger can then be removed from the frame. Save this trigger and original trigger pin for any future shipments to the manufacturer for service work. Kel-Tec would normally return your firearm to its original factory condition, and your aluminum trigger could get misplaced.


Finish cleaning any remaining oil or grease from the frame and trigger cutout area.


Remove the hammer/spring assembly* from the frame by pushing out the hammer axis.

Set these aside for now.

Important: Removing this assembly expedites the frame/grip clearances later without having to attach the grip assembly.

* This photo is of a PF-9 Hammer and Frame.

Page 7

Trigger Installation

  "Hybrid" trigger installation steps will be directed to the Hybrid Trigger Supplement (link at left).
Directions back to the next step in this Trigger Guide will be provided there.

The aluminum trigger will be installed much the same as the stock trigger with a few exceptions.
The factory trigger pin is “barbed” so that it will not work loose from the plastic trigger.
The replacement pin has been trimmed to provide a snug fit in the aluminum trigger.
A Nyloc or Loctite-coated setscrew will also provide a mechanical “lock” for the new trigger pin.

We will use gun grease instead of oil initially on the trigger, axis and frame.
Once the gun is operational, oil can then be used on these parts during regular maintenance.
Place a drop of oil through the top frame access hole. (See “Firearm Lubrication” at



Before beginning, make sure that the trigger axis (Page 9, Figure 1) will fit inside the large hole in the aluminum trigger. It should be a snug fit. Do not sand if possible.


Apply a thin coat of gun grease to the sides of the trigger around the larger ¼” axis hole. Also apply a thin coat inside the hole.

Carefully position the trigger into the frame, aligned with the axis hole.

Page 8


Apply a thin film of gun grease to the pivot surfaces of the trigger axis.

Insert the axis through the frame and trigger.

"Hybrid" triggers - go to Hybrid Trigger Supplement: "First Pass"

Axis Tab Clearance Checks

Line up the holes in the trigger and axis (use the 2mm punch if necessary.) Insert the new trigger pin through both components.

This should be a snug fit. Use the 3mm punch to seat the pin until it goes all the way in. Do not sand or file the pin.

Page 9

Turn the frame upside down on a wooden block. Make sure that the ejector hangs off the edge of the block.

With the frame upside down, finish seating the trigger pin by placing the 3mm large punch onto the pin, and tapping it very lightly with the end of a screwdriver handle.

(DO NOT use the smaller 2mm punch, as it may deform the head of the pin)

 IMPORTANT: The head of the pin must be seated completely into the countersunk hole.

(see Page 13, Figure 1)


Access Hole Check

Looking down at the access hole in the top of the frame, make sure that the end of the trigger pin is FLUSH with the top of the trigger. It cannot protrude more than 1/32” or it will jam in the frame. If this is the case, remove and trim the end of the pin with sandpaper or a small file until it fits properly.

Page 10

With the trigger in the full rearward position, there should be little or no gap between the front of the axis tab and the frame cutout.

Any gap should be made VERY small to allow for over-travel after the trigger break. Too much gap will result in the hammer not releasing.

Note: The new ATP11T and ATP11A triggers are engineered to fit with little or NO gap.

When filing or sanding the trigger to increase over-travel, try to keep some gap here if possible.

With the trigger in the full forward position, the axis tab should contact the rear edge of the frame pocket. If it doesn’t contact it, you will need to slightly trim the upper side edges of the trigger just above the finger guard where it contacts the frame cutout edge. (See Page 23)

Grip Cutout Clearance Checks


Insert the frame with the trigger temporarily installed into the grip. Starting at the front of the grip, line up the frame pinhole, and then lower the rear of the frame into the grip. Press the frame into the grip until the frame pinholes all line up.

Page 11


The trigger must clear the back of the grip cutout, and contact the inside of the frame cutout just above it.

 If the trigger travels freely without interference, skip to bottom of page.

If the trigger rubs or feels like it drags on any part of the grip, locate the source of the interference. Remove the frame from the grip, and trim the grip (next step).


Grip Modification

If your trigger contacts the plastic grip cutout in any way before reaching the aluminum frame cutout, remove the frame/trigger assembly from the grip.

Use a piece of #280 grit sandpaper rolled around a “BIC” pen or similar cylindrical object to remove a bit of this edge and re-assemble to check. The P-11 plastic grip cutout may have a straight rear edge, but trimming is the same.

Repeat this process until the trigger clears the plastic grip cutout.


"Hybrid" triggers ONLYskip to  Trigger Final Assembly   (bottom of Pg 13)

Standard Triggers:

Do not skip this step!

The front end of the P-11 trigger opening MUST be trimmed to allow the trigger pinch guard to seat against the frame in the reset position. Mark the cut line on the grip as shown.

Page 12


Using a round file, remove enough grip material to allow the trigger to clear the grip completely. Be careful to avoid scratching or gouging other areas of the grip with the file. Trim any rough edges with a sharp knife or sandpaper. Finish with the sandpaper rolled around a “BIC” pen or similar.

The pinch guard “bump” at the top of the trigger should clear the front edge of the grip completely.


* Note that the head of the trigger pin is seated inside the countersunk hole in the trigger. It should always appear recessed in the hole. This should be a point of regular inspection. If the pin begins to work its way out, the setscrew should be loosened, the pin reseated, and the setscrew retightened.

Trigger Final Assembly

Remove the frame from the grip, and set the grip aside.

"Hybrid" triggers - remove setscrew before next step.

Line up the top of the trigger pin with the access hole in the frame. Using the 2mm punch, push the trigger pin back out about half way until you can see the end just protruding into the center of the axis.

Page 13


Insert the trigger spring into the axis with the “arm” pointing toward the front of the frame, and the “hoop” positioned so the trigger pin will pass through it.


While pushing down on the trigger spring, push the trigger pin into the trigger. This should be a tight fit, so you might have to wiggle the alignment or twist the pin slightly to get it in.

 IMPORTANT: Keep firm downward pressure on the spring with the “arm” of the spring in the position shown, or the trigger pin may hang up on the small hoop at the end of the spring.

Using the larger 3mm punch, PUSH the pin all the way into the hole.


"Hybrid" triggers - go to Hybrid Trigger Supplement: "Second Pass"

"Standard" triggers:

Turn the frame upside down on a wooden block. Make sure that the ejector hangs off the edge of the block.

Page 14


Seat the trigger pin by placing the larger 3mm punch onto the pin, and tapping it lightly with the end of a screwdriver handle. DO NOT use the 2mm punch, as it may deform the head of the pin!

IMPORTANT: DO NOT skip this step! The head of the pin must be seated completely up inside the countersunk hole. (Page 13, Figure 2)

Check that the top of the pin is flush with the top of the trigger, by viewing through the access hole in the top of the frame. (Page 10, Figure 3)

Make sure the setscrew hole is clean and free of debris or oil. Start the provided #6-32 stainless setscrew into the threaded hole at the front saddle of the trigger. There is a patch of yellow or red Loctite on the setscrew threads. This is designed for a few installs before the coating loses its locking capability. Heat is not needed to loosen yellow Loctite.

 Blue Loctite #242 can be used if the coating wears off from repeated use. Apply a small drop with a toothpick. Heat is needed to loosen blue or red Loctite to remove the setscrew. A butane lighter or heat gun will provide sufficient heat.


Run the setscrew down onto the trigger pin using the included 1/16” allen wrench (not shown). There will be resistance from the Locktite patch, but it will still go in smoothly until it firmly contacts the trigger pin. DO NOT OVER-TIGHTEN! A snug fit is all that is needed. (For technical types – a #6-32 screw in aluminum is suggested to be 5.3 inch-pounds of torque).
Check that the  trigger pin is locked by pushing on it with the small punch from the top access hole.

Careful! If you strip out the allen socket hole in the setscrew, do not try to hammer the trigger pin back out past the setscrew, or you may damage the axis hole in the frame. Contact Northwood for assistance.


Page 15


Re-Install Hammer

Place a drop of gun oil both on the hammer axis, and both sides of the thicker section of the hammer. Insert these components into the frame. The hammer axis should go in easily.





 Frame Re-Assembly

First, make sure that the trigger moves freely in the frame.
You may feel a slight drag from the trigger spring arm rubbing the frame.
Once the spring is positioned into the trigger bar slot, this will no longer be a factor.





On the right side of the frame, lightly apply gun grease to the area under the trigger axis, and to the top of the axis around the trigger arm nub.


Apply a thin coat of grease to the rear frame around the hammer axis pin area.

Page 16


Apply a thin coat of grease to the frame side of the slide stop.


Apply grease to the spring slot along the top edge.


Set aside.



Apply a thin coat of grease to the “frame” side of the trigger bar.


Apply grease to the spring slot along the bottom edge of the bar.


On the right side of the frame, place the trigger bar over the nub on the trigger axis at the front end, and the hammer axis on the rear end. (The small tab at the rear of the trigger bar will point inward.) Apply a light coat of grease to the trigger bar.

Page 17


Grasping the frame and trigger bar with one hand, hook the trigger spring with a plastic ballpoint pen cap, or your fingernail, and carefully turn the spring counter-clockwise over the trigger bar, and into the slot on the bottom of the bar.

Hold this assembly with a thumb or finger, as the trigger bar will fly away and spread grease everywhere.

Turning the frame over, (and while still holding the trigger bar in place), install the slide stop lever onto the trigger axis with the tab positioned in its hole as shown.


Apply a small amount of grease to the frame where the long end of the spring will set.


Page 18


Place the slide stop spring onto the upper nub cutout with the long side toward the top. Again with your pen cap or fingernail, pull the short side of the spring back into the greased slot in the top of the lever.


Spread a thin film of grease over this area.


While holding the right and left components against the frame, lower the hammer spring retainer and spring into the grip, and insert the front of the frame into the grip. As the frame assembly moves down into the grip, you may need to pull back on the trigger slightly to clear the cutout.


Seat the frame assembly into the grip. If it seems stuck, pull the trigger slightly to clear the grip cutout.


All three of the frame pin holes should line up, but do not install the frame pins yet.

Page 19


Note: When resetting the Hammer Spring in this step, the hammer should be in the released position, as shown on Page 2, in Fig 2. In the same way it was done for disassembly, with the pistol in one hand as shown, push the spring retainer up through the mag well, onto the lip of its recess slot.


Remove the screwdriver, and finish pushing the retainer into its slot with your thumb. It will snap into place.

Page 20


Clearance Checks


Hold the top of the hammer from moving forward with one hand (use a pad for your finger), and slowly pull the trigger. Find the spot where the trigger “breaks”, and note how much free “over-travel” there is before the trigger contacts the frame. (See below)

Over-Travel Check

 You MUST have at least 1/8” free travel (over-travel measured at the tip of the trigger) remaining after the hammer release.


If the trigger does not release the hammer before reaching the 1/8” free-travel mark, STOP. The trigger may need to be trimmed slightly. (See Page 22)


Pre-Travel Check

 Temporarily assemble your slide/barrel onto your frame, and insert the assembly pin. With the slide in place, you MUST have at least 1/8” of free travel (measured at the tip of the trigger) from the reset position, before the trigger begins cocking the hammer.

 If the trigger does not have at least 1/8” of free-travel, STOP. The top edges of the trigger may need to be trimmed slightly. (See Page 23)


 Page 21

Trigger/Grip Modifications

The latest version triggers are designed to work without modification in most PF-9, P-11 and P-40s.
If for some reason, your trigger will not work as advertised, contact
before attempting to modify your trigger. If you are not comfortable doing your own modifications,
your trigger can be returned for a full refund, provided it is still in its original unmodified condition.
Use the "Contact Us" link above to request our current shipping address for returns.


Too little over-travel (or hammer not releasing)

The adjustment needed to increase over-travel after the hammer release is to remove material along the
cylindrical back side of the trigger. This can easily be done with #280-#400 grit sandpaper.

(No returns will be accepted if this custom fitting has been performed.)
Please email Northwood Components for technical assistance with this procedure.

Tip: Before removing trigger for trimming, "paint" the back surface lightly with a magic marker, fingernail
polish, or gun grease, etc. Pull the trigger back into the frame to see where it is making contact.
This will be the area that needs sanding. This contact point will wear in slowly - don't trim too much at first.


Remove the frame/trigger assembly from the grip, and remove the trigger from the frame. (Pages 2 through 7)

Keeping the same angle as the machine cut at all times, sand or file evenly around the back surface, removing only a small amount of material at a time. This is best done with the trigger out of the frame for better control on keeping the angle constant, and a cylindrical surface.

Frame and grip assembly can be assembled without grease to re-check for adequate over-travel clearance. When trigger is trimmed sufficiently, begin again at Page 8 using gun grease for final assembly.


When sanding and removing material, try to maintain a small “gap” between the trigger axis and the front edge of the frame pocket (as pictured earlier). Check progress by assembling these parts (Page 8 thru 20) without grease, and testing until sufficient clearance is achieved. The gap can be almost non-existent, as long as the trigger contacts the frame at the same time. Maintaining even a minimal gap will relieve undue torque on the trigger pin when firing.


Note: The new ATP11T and ATP11A triggers are engineered to fit with little or NO gap.



Page 22

Not Enough Pre-Travel (or hammer is not resetting)


**Although each trigger has been trimmed to fit the newer P-11s before being shipped,
there may be an adjustment needed to allow for an earlier frame with slightly different specs.

The adjustment to increase pre-travel (free travel prior to beginning the hammer cocking sequence)
is to remove a small amount of material from the top of the finger guard of the trigger,
on each side edge where it contacts the front edge of the frame cutout.
This can be done with a small 1/8” diameter round file. (See photo below.)
Do not file or modify the gun frame, as this will void the Kel-Tec  warranty.


Determine where the contact points are by pressing the trigger forward against the frame to score the trigger. You will see marks on the upper side edges of the finger guard as indicated in the photo at right.


Remove the frame/trigger assembly from the grip. (Page 2 through Page 7). To prevent aluminum filings from fouling your gun, completely remove your trigger for this procedure.

Using a small round file, carefully remove material from the edge of the TRIGGER (not the frame) indicated in the upper photo. Remove only a small amount of material at a time, until the axis tab comes in contact with the rear of the internal frame cutout. (Be sure trigger pin is inserted each time this check is made.)

 Page 23

Final Assembly

Once the hammer release function, trigger reset function, and minimum clearances have been established, and the trigger moves freely, continue with completing the frame assembly:


Install the three frame pins into the grip and frame, tapping lightly with the screwdriver handle.



If you are satisfied with the fit and operation of the trigger, then lube and assemble
the remaining firearm components, and wipe down. Check the firearm for proper operation.


To dry fire the P-11, there MUST be a snap cap in the chamber.


 **  If you are not happy with the trigger for any reason, please contact
for our current return address, and a full refund. The trigger must be in its original, unmodified condition.
No returns will be accepted if they have been sanded, filed, polished, or otherwise modified in any way.

IMPORTANT:  These parts may require a significant level of mechanical skill to install. We do not recommend
purchasing replacement or upgrade parts if you have little or no experience with firearms. If problems occur
with your firearm due to improper replacement or assembly of a part, repairs may not be covered under its
warranty.  A gunsmith may be able to correct any issues if the weapon is sent in to them, however shipping
costs must be covered as well as any replacement parts needed due to improper assembly.

These parts are available to qualified owners that prefer to replace or install parts on their own rather than
send the weapon in for upgrades or service work.  This guide is intended for those with the knowledge and
experience to make these replacements.

AGREEMENT:   Northwood Components, LLC shall not be responsible for any changes made to your firearm by you or any
Purchaser agrees that they have read and understand the trigger installation process described in the Aluminum Trigger Guide.
Purchaser agrees to protect, indemnify, and hold Northwood Components LLC, it’s owners and assigns harmless from and
against any and all loss, costs, expenses damage or liability arising out of any accident or other occurrence while installing or
using this product causing injury to any person or property.

For a copy of this document, "Save As..." a Web Archive or a Complete Web Page.
You can then view it offline.

This guide has been revised for the Kel-Tec P-11, and P-40,
and was reviewed by Skunkworks Beta Test Group
for trigger installation.


Copyright © 2012-2019 Northwood Components

Rev 27D

Page 24