BACKGROUND INFO:

I've always hated the loud clicky noise of any mouse since I don't like bothering other people while I'm clicking away in a videogame or simply browsing the web. For this reason, I decided to modify my first proper gaming mouse to try to make it as quiet as possible.

This required sacrificing the mouse in case I f***d up the microswitches. So the mouse I decided to mod, and with much success, was the ASUS ROG SICA. This mouse had the advantage of having a socket for swapping out the microswitches almost instantly (you still had to unscrew the bottom) so I didn't have to solder and desolder repeatedly the 3 pins and riskind damaging the casing with the heat.

I discovered that by flipping the microswitch 180 degrees and also flipping the mechanism, you could simply make the microswitch noiseless but by sacrificing the tactile feedback and making the switch incredibly sensitive to touch.

PROS:

Having a mouse with swappable switches doesn't require soldering whatsoever.
It can be modified in under 10 minutes.
This mod is cost free and can be done with a few tools.
Not bothering anyone anymore.

CONS:

Risking having to reassemble the TINY mechanism that makes the switch works if while disassembling it falls out.
If you don't have a mouse with swappable switches you'll need some soldering skills and maybe some extra switches in case you melt them.

Step 1: STEP 1: Tools

You will need the following tools:

Philips head screwdriver
1 inch of flexible copper wire (the one that has many copper strands)
A razor blade or a very thin screwdriver to pry apart the plastic tabs of the microswitch.
A wire nipper or some scissors.

The following tools are highly recommended if you don't have small fingers:

Small tweezers (for reassembling the microswitch)

If you don't have a mouse with swappable switches I'd recommend you to have:

Soldering iron
Tin with rosin core (or similar)
Desoldering vacuum pump (Desoldering wick is not recommended since it will induce too much heat in the plastic casing and might or will melt the switch)

You might have a mouse that has different head screws so take that in consideration.

IF YOU'RE WILLING TO CONTINUE BE ADVISED THAT YOU MIGHT BREAK SOMETHING OR VOID YOUR WARRANTY. IF YOU MAKE ANY MISTAKE WHILE DISASSEMBLING THE MICROSWITCH IT WILL BE FRUSTRATING TO PUT IT BACK TOGETHER, SO BE ADVISED.

Step 2: STEP 2: Disassembly of the Mouse

I'll be using the ASUS ROG GLADIUS II for this demonstration because my last mouse, the ROG SICA broke while I got angry while playing some games, so you can take my word that the mouse will not last you more than 5 years (mine did only 3 years).

First off, unplug the mouse from your computer while working.

You will need to locate the screws in the under side of your device

If you see rubber plugs, try to lift them with a fine flat-head screwdriver.
If the screws are not there, they might be hidden under the teflon pads. You can remove them with an exacto knife or a razorblade so you don't damage the adhesive.
If you still can't find the crews, try to use the tip of the screwdriver or your nail to scratch the label and feel if there are any screw holes under it. You might feel a small one right in the middle but this is normally from the injection molding of the plastic shell.
If you can't find the screws this might mean that your mouse is put together with plastic tabs inside, so try to use something to pry it open. Be very careful if you're using any sharp objects while applying force!

Once you have located the screws, proceed to unscrew them with the right screwdriver bit and open the mouse.

Step 3: STEP 3: Locating the Microswitch

In the image you can see the innerds of my mouse. You can clearly see there are TWO blue microswitches from Omron in the left side of the board. In the bottom there are THREE other microswitches that are from Khalil.

If you happen to have a microswitch that looks like the second image, with the opening in the left side of the gray contact, this means you can't finish this mod because the inside is different that most switches. See in STEP 4 how the switch should look inside to confirm you can continue.

There is a high chance you can't complete this mod if the microswitches look like in picture 3 because the plastic taps are on the sides any you won't be able to turn around the switch because they have a part that prevents it from it.

Switches that might work for this project (the ones in bold have been successfully modded):

OMRON D2FC-F-7N
OMRON D2FC-F-7N(10M)
OMRON D2FC-F-7N(20M)
OMRON D2FC-F-K(50M)

Switches that have a high chance of not working:

OMRON D2F
OMRON D2F-F
OMRON D2F-01 / D2F-01L / D2F-01FL / D2F-01F-T / D2F-F-3-7
Any other switch that looks like Picture 2 or Picture 3 (they all have in common the tabs in the side and the slot near the switch)

Step 4: STEP 4: Disassembling the Switch

Remove the switch from the board and set the mouse aside.

With a very fine blade, pry one of the tabs until you see the top lifting off. DON'T RUSH and open it completely, you have to pry the other tab first or else you might risk breaking the mechanism. See picture 2.

Lift the top of the swith while remembering how it was put together.

From step 3: If your switch looks like picture 3 with the metal arch under and not over, and doesn't have the underside of the case lifted like in picture 4, then you can proceed (picture 4 is from the switch D2F-01F)

Step 5: STEP 5: Reassembling the Switch Backwards

We need to assemble the top part backwards but you'll notice it doesn't fit (picture 1). Use the exacto knife to cut the tabs (picture 2)

Use the tweezers to put the contact pin in the top casing and while it's resting on top of the table, reassemble the switch backwards with the metal arch over the blue contact pin (refer to step 4).

Step 6: STEP 6: Adding a Jumper Wire

Now grab the flexible cable and cut it open to reveal the strands of copper.

Cut only one strand per switch and wrap it around pin 1 and 3 of the switch like in picture 4. Make sure it won't touch the middle pin. If you have desoldered the switch, this step isn't needed since you can solder a jumper from pin 1 to 3 in the PCB.

I don't exactly know why this step is needed but I've found that the switch doesn't work if you skip it.

The finished product should look like picture 3.

Step 7: STEP 7: Reassembling the Mouse

Now you can assemble the mouse again and test if it works.

You should still feel a bit of tactile feedback from the mouse but almost no noise. If this is the case, you have successfully modded a mouse... well, just one button. Now proceed to mod all the other ones. You'll notice the further you use them, the more feedback they have.

Keep in mind that if you mod the scrolling wheel you won't be able to scroll without pressing the button. Also, macro buttons are not recommended since you might misclick while moving the mouse around.

Troubleshooting:

If the switch doesn't work it might be because the jumper doesn't have a good contact with the pins. Make sure to wrap it around at least 2 times. Don't use solder because it will make the pins thicker and they won't fit flush with the PCB.
If you don't feel any tactile feedback whatsoever, make sure the microswitch is flush with the PCB. If it's not it means the switch is always on and won't click.
If you broke the switch, you might have realised the copper contact pin is made of 2 different pieces: the arch and the lever. I recommend you to open another switch to look how it's assembled and use your fingers to put it back together. Tweezers are not recommended since you might bend the arch while doing so.

Step 8: How It Works

The microswitch is composed of a gold contact and and actuating button like in the image.

In the IDLE state, the switch is in Normally Closed (NC) state and it's like the button isn't pressed. This is the IDLE state since the metal arch I was talking about earlier makes force against the common terminal and it will remain in the NC state until force is applied in the button to move it downward and touch the Normally Open (NO) terminal.

If you turn around the mechanism and put the button on top of the arch, the travelling time is basically halved since the contact acts like a lever. This also means the force required is halved and the contact will NEVER touch the NC terminal. This is why we have to add the wire from the Common to the NC terminal. This looks ok but it means the NC terminal will always be ON, but for some reason the mouse still detects the click.

Also, the feedback is removed because when you overcome the force of the arch the contact hits the NO terminal like a bell and gives you the tactile feedback. Similar results can be achieved in mechanical keyboards by removing the feedback pin. Blue mechanical key example