Tanner's Gun Reviews

   By Mike Coviello (Tanner)

Installation Instructions & Review


Cominolli Glock Manual Safety

GLOCK 19 Review GLOCK 26 Review
Exploded View & Parts Trigger Job
Slide Disassembly Trigger Removal
Magazine Disassembly Diagnosing & Repairing
Failure To Extract Extended Slide Lock
Extended Mag Release All Glock Reviews
Glock 19 Pistol
Glock 19 Pistol
Glock 26 Pistol, Ammo & Magazine
Glock 26 Pistol
Glock 17
Glock 17 Pistol
Glock Firing Pin Assembly
Firing Pin

What Is The Cominolli Safety?

The Cominolli Safety is an aftermarket product for Glocks that adds a manual thumb safety to the pistol. The product is called a Cominolli MANUAL SAFETY KIT FOR GLOCK®, and is available at the Cominolli website (cominolli.com) and other gun parts dealers. It costs about $90.00 USD +S/H.

Click here for a simple explanation of how the Cominolli Safety works.

The installation of a Cominolli Safety is a Glock modification that requires cutting a permanent slot into the frame of your Glock pistol. A paper template is provided showing where to cut the slot. Cutting the slot with the paper template is "do-able" but you risk cutting an uneven or sloppy cut which may ruin the looks of your Glock or hamper the function of the safety.

Cominolli makes and sells a Cominolli Frame Slotting Fixture (For Manual Safety Kit-MSK Glock Pistols) for $87.00 USD +S/H (see pictures below). Get the Frame Slotting Fixture if you want to do a professional installation. The slotting fixture eliminates (or greatly reduces) the chances of screwing up your Glock.

The Cominolli Safety is a do-it-yourself installation. Alternatively, you can pay someone to do it for you, but you may have to mail your gun to professional installers for the modification.

Cominolli Glock Manual Safety

When "ON SAFE" (Lever up) the slide will function normally, allowing loading and unloading while the trigger bar is locked in place.

When "OFF SAFE" (Lever Down) weapon is ready to fire.


Cominolli Manual Safety Kit For Glocks
(The Package)
Cominolli Manual Safety Kit Parts 3/32" End Mill Tool For Cutting The Slot Cominolli Manual Safety Kit Instruction Sheet Cominolli Installation Templates

Cominolli Frame Slotting Fixture
(For Manual Safety Kit -MSK Glock Pistols)

Cominolli Frame Slotting Fixture Package Contents

Cominolli Frame Slotting Fixture Cover Sheet For Manual Safety Kit-MSK Glock Pistols Cominolli Frame Slotting Fixture
(Front & Back Sides)
Cominolli Frame Slotting
Fixture Guide

COMINOLLI Glock MANUAL SAFETY Kit Installation Instructions

1. Remove the slide and barrel assembly from the frame per Glock Field Strip Instructions.
2. Remove the trigger housing block and trigger group from the frame per Glock Trigger Removal & Installation Instructions.

Cominolli Fig. 1

If Cutting Slot By Template
Perform the following if you chose to cut the slot into the frame using the template provided (you did not purchase the frame slotting fixture).

3. Review frame diagram, Fig. 1, note different dimensions for 45 ACP and 10mm pistols and all other models.

4. Using the correct dimensions for your particular pistol, (see template card), mark out the frame for the slot that is required for the manual safety. Cut the slot per drawing.

If Cutting Slot By Fixture
Perform the following if you purchased the frame slotting fixture.

Attach Glock pistol to the frame slotting fixture with provided pins as shown.

5. Cut the slot as marketed on your frame - work slowly and carefully using a dremel tool and a small cutting burr or a small diameter coarse round file.

Completed Slot Cut Into Glock Frame

6. Be sure the slot you have is clean and free of plastic particles.
7. Remove the trigger bar assembly, trigger spring, ejector and connector from your trigger mechanism housing block.
8. Fit your ejector and connector into the new Cominolli Manual Safety Trigger Mechanism housing block.

9. Lube with a light grease the contact surfaces of the component parts of the Manual Safety Kit.

10. Assemble the component parts as shown in Fig. 2 - at the same time fit trigger bar and trigger spring into trigger mechanism housing.

IMPORTANT: Pressure spring should be fit in place with high points at 12:00 and 6:00 facing out from trigger mechanism housing against pressure plate.

Trigger Bar Guide should be forward and safety lever should be in safe (UP) position as shown in Fig. 2.

Fit drop safe end of the trigger bar's cruciform though Trigger Bar Guide of safety assembly.

11. Install the entire assembly into frame and insert all frame pins.

12. Fit slide back onto frame and bench test.

Cominolli Manual Safety

A few days ago my friend brought up the subject of getting a manual safety for his Glock 26. He carries his Glock 26 in a fanny pack. He would like to carry it with a round in the chamber but he is concerned with taking the gun out in a high stress situation and inadvertently hitting the trigger. He decided to look into the various safety options for Glocks and the Cominolli Safety caught his eye. After researching the product, he ordered one for his Glock 26. The following is an email comment he made after he completed the installation of his Cominolli Glock Manual Safety.

"I put the Cominolli safety on the 26. It was very easy and simple. It took less than an hour and if I had to do it again, it would take about 20 minutes. It is a very simple and neat design and should be fool proof. It physically locks the trigger bar when the gun is in the ready state. The safety snaps on and off easily and it is in an excellent ergonomic position to actuate it. Based on the experience thus far, I would highly recommend it. I will bring it Thursday so we can try it. I have attached the pictures I took during different phases of the modification. You can select the ones you feel are appropriate."

FINDING INFORMATION ABOUT THE COMINOLLI GLOCK MANUAL SAFETY - If you search the internet for the Cominolli manual safety for a Glock you will probably find many debates about whether Glocks need manual safeties or not, but you won't find much about how the Cominolli Safety works or the details about how to install it. Surprisingly, even the Cominolli website has little information about the product (see below). That is what this web page will try to provide.

Cominolli Glock Manual Safety description

Safety system offers a manual safety lever while retaining all 3 internal Glock safeties. Parts are chrome-plated stainless steel with a black matte finish. Frame modification and gunsmith installation will be required.

  1. Ergonomically designed and located

  2. Positive engagement and disengagement

  3. With manual safety engaged, all three Glock passive safeties are locked in place

  4. Pistol can be loaded and unloaded with manual safety engaged, thus diminishing the chance of an unintentional discharge

  5. Long-wearing Stainless Steel, hard chrome plated parts with matte black tactical finish

Cominolli Glock Safety Evaluation

My friend brought his Glock 26 with the newly installed Cominolli Safety to the range for us to shoot and evaluate.

My Friend's Evaluation Of The Cominolli Glock 26 Safety

  1. Installation of the Cominolli Safety was easy and only took about half hour. The next one he does will probably only take 20 minutes.(note- my friend is a pretty smart guy though and a retired engineer).

  2. Cutting the slot in the Glock was simple and fool proof. The actual cut only took about 10-15 seconds.

  3. Using the Cominolli Installation Jig makes for a professional looking installation.

  4. The Cominolli Glock Manual Safety works exactly as advertised.

  5. He is very impressed with the elegance of the design of the safety and has confidence in it's operation and function.

  6. He will likely modify his Glock 17 with a Cominolli Safety.

  7. He had NO NEGATIVE REMARKS about the Cominolli Safety.

My Evaluation Of The Cominolli Glock 26 Safety

  1. The Cominolli Glock Safety didn't change the looks of his Glock 26. The Glock 26 with the Cominolli Safety looked just like my standard Glock 26 except that it had an unobtrusive thumb safety. The slot cut into the Glock looked like it was done at the factory.

  2. The safety lever was very easy to operate with my thumb. It didn't take much force to move it down into the fire position and you can feel and hear a noticeable click when it locks in.

  3. I tried to fire the gun with the safety ON SAFE. The trigger would not move back and the gun would not fire. I repeated this several times.

  4. With a simple flick of my thumb the safety lever moved down and the gun fired. After one session at the range getting used to the new safety would become second nature.

  5. I found that shooting the gun with the safety

  6. We showed the Glock Safety to a couple other shooters that we know. They were not Glock enthusiasts but were very impressed with the installation of the safety and made jokes about my friend buying his gun from the factory that way.

  7. We were both wondering why the Glock Company does not offer this option on their pistols. It seems like it would open up another market for them.


Do Glocks Have Manual Safeties?

No, factory Glocks do not have manual safeties built into them. Aftermarket products such as the Cominolli Manual Safety Kit For Glocks are available for purchase and installation.

Does The Cominolli Safety Void The Glock Warranty?

No, it is reported that the Cominolli Safety modification to a Glock does not void the GLOCK® warranty.

Do You Need A Manual Safety ON A Glock?

There is much debate on whether you need a manual safety on a Glock. This web page is not a forum for the pros and cons of Glock manual safeties other than what is listed below.

Why Glocks Need Manual Safeties

  1. For carry purposes, if you are concerned that someone will take your gun away from you and use it against you a manual safety on your Glock may confuse the bad guy or buy you a few seconds to act.

  2. For carry purposes, if you don't carry your Glock in suitable holster but rather in a fanny pack or in your pocket a manual safety offers and extra level of safety against accidental discharge.

Which Glock Pistol Models Can The Cominolli Safety Be Installed In?

The Cominolli Safety will install into all models of the GLOCK® except Glock 36.

How Does The Cominolli Safety Work?

Once installed, the Cominolli Safety works just like all thumb safeties on pistols. Just flip it down with your thumb to fire. Flip it up to be safe. When the safety is engaged you can load or unload the Glock with an extra level of confidence and safety.

What Is The Cominolli Safety Made Of?

The Cominolli Safety is made of chrome plated stainless steel and has a black matte finish.


Cominolli Safety Questions & Comments


Subject: Help With Cominolli Safety Installation Problems
Sent: October 30, 2011

Hello, I have installed 4 of these safetys and on with the addition of lake storm barrels I have two model 27 s a model 22 and a model 21 sf I have had trouble with the older model model 27 stove topping or just not ejecting. any ideas about this I had to do alot of work to get the model 21 to come together I cant remember if I have a fail to eject with the model 22 0r the 21 . All but the older model 27 are all new, I used the jig to cut the opening for the safety. Any help would really help me out.

Response - Allen
Sorry, but I can't help you.
My friend added the Cominolli safety to his Glock 26 and had no problems whatsoever.
The only thing that I could suggest to you is to go the Cominolli website (cominolli.com) and ask them your questions if you feel your problems are related to the new installations.
Good luck,



$90.00 USD +S/H

Helps Prevent Unintentional Discharges. Manually engaged safety lever provides an extra level of security and safety for Glock owners. Blocks trigger movement, allows the slide to be cycled and pistol loaded or unloaded with the safety on. Operates easily with your right-hand thumb. Contact pad is easy to engage, yet won’t interfere with holster fit. All Glock passive safeties continue to function normally. Gunsmith installation is recommended.

SPECS: Thumb Safety - Plastic trigger housing, black. Steel parts, black thumb pad. Pad - ½" (12.7mm) long, ¼" (6.35mm) wide. Includes instructions with positioning template, replacement trigger housing, plus thumb lever, detent pressure plate, spring and trigger bar guide. Fits all models except Model 36.


Safety Installation Jig
$87.00 USD +S/H

Helps Prevent Unintentional Discharge. Holds your Glock frame securely and has two, machined slots that correspond with the cut you’ll have to make to install Cominolli’s Manual Thumb Safety Slot marked “SM” is for 9mm, .40 S&W, and .357 SIG; slot marked “LG” is for .45 ACP and 10mm. NOW INCLUDES the 3⁄32" End Mill in the kit! Just supply your own high-speed rotary tool to properly make the cut. Delrin® guide makes it easy to cut the correct angle.

SPECS: Safety Installation Jig - Aluminum, silver matte finish. 3½" (9cm) long, 5" (12.7cm) high, 3⁄8" (9.5mm) thick. Includes frame locating pins and delrin guide. 3⁄32" End Mill - High speed steel. 3⁄32" (2.4mm) diameter, 1⁄8" (4.8mm) shank. Single end, center cut.



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MIKE COVIELLO is a former aerospace engineer, now Web Designer/SEO Consultant. Hobbies include shooting zombies & reloading ammunition.