This guide was made and posted by pxlnght on r/mk. I just wanted it listed here among the other useful stuff.
The three viable sockets are 0305, 7305, and 0279. All three work, but all 3 have benefits/drawbacks.
0305 - Reasonably cheap, and fit near any keyboard. Compared to the 7305, they have a thicker lip. The drawbacks to this socket are it's long tail. If you're using a board with very tight spacing, they may be too tall and touch the bottom of the board. You can fix this by sanding, but that's a lot of work. P/N used: 0305-2-15-80-47-80-10-0 https://hu.mouser.com/ProductDetail/mill-max/0305-2-15-15-47-27-10-0/?qs=HJ60cwpDT2zFqCydXwr0jg==&countrycode=US¤cycode=USD
7305 - These are just about identical to the 0305, but they have a shorter tail and shorter lip. The short tail makes them ideal for tight builds. They're gold plated depending on the exact model you select. These are one size fits all, but they're annoying as heck to install due to the short tail. When I buy these, I always buy 10 extra because it's nearly impossible to get through an entire build without borking a few and getting solder inside. P/N used: 7305-0-15-15-47-27-10-0
0279 - They have very long closed tails, and hexagonal lips before the main lip to secure itself in place. No solder required (disclaimer: solder required anyways). If you've got a PCB with nice tolerances on the switch holes, you can press these into place with zero problems. Now, realizing we're not in a perfect world, the tolerances are never perfect. Some holes are too small. When you push fit these into a smaller hole, they expand the hole and frick the heck out of the leads. You'll need to make a jump from a nearby switch to fix this. I've done 2 boards with these sockets and both needed 2 jumps. I use them anyways because it's much faster to install these and jump them afterwards (45mins-1hour) than to solder in 0305's or 7305's (like 2 hours or more). The speed scales with the # of switches you have to solder. Fullsize boards are a BREEZE with these, lemmie tell ya. THESE ARE NOT A GOOD OPTION IF YOUR PCB DOES NOT HAVE CIRCULAR HOLES. P/N used: 0279-0-15-01-47-27-10-0
Utilize GBs where you can, of course, as it'll be much cheaper than buying on your own. If you can't, use Octopart to find the cheapest place you can snag the sockets. When I buy sockets, I tend to toss all 3 part numbers into Octopart and pick the cheapest one. I also tend to look at other sockets that are similar, and if I consider them viable I give those a go. Frankly, when a socket becomes popular, the price of the socket shoots up. If you're the first person to find a viable socket, you're in luck bucko, get some cheap while you can.
If you want to run a GB, ask me and I'll add a GB section to this 'guide'.
For all soldering: use a small tip and use thin solder. I use kester 0.031 in. 24-6337-0027
0305 and 7305:
Put sockets on a switch.
Insert switch where it belongs, with sockets on the legs.
Repeat 1-4 until done. Use like 10 switches at a time. Use switches you don't care about so that when you inevitably solder a socket into it, it's no biggie.
0305 and 7305 help
Solder inside socket, but you can remove the switch:
Take iron, press it onto the back of the socket. This will push it out a bit after it heats up. Remove iron. Stand PCB on it's side, use tweezers or whatever you've got, hold onto the top of the socket, and press the iron on the back of the socket again. Once it heats up, use the tweezers or whatevs to pull the socket out. Use the hand with the tweezers to push on the PCB if needed.
Solder inside socket, and you CANT remove the switch:
Heat up the socket and pull on the switch until it comes out. Usually the socket will come out with the switch and you can just toss it in the garbage. If the socket stays, but the switch comes out, see #1.
Socket isn't flush with board.
Rest 250C iron on the top of the socket for about 1 second. Push socket down with conservative force. Should go down fairly easily. Wait longer than a second for the solder to melt if needed. Don't push too hard.
0) Make sure PCB is placed on top of something so there's room to press the sockets in.
Place sockets in holes via hand or tweezer.
Heat iron to about 250C.
Rest iron on socket for about 1 second.
Push socket into hole.
Repeat 0-4 until done.
Check all switches for continuity. Make jumps where needed.
0279 install album:https://imgur.com/a/II8LmDm
0279 jump album:https://imgur.com/a/cfr4Ess
When you put keycaps on your stablizers, it might push the PCB off of the switches. I like to leave the board open until switches AND caps are installed, push everything to fit again, then close up the case.
God tier QOL upgrade: add something non-conductive underneath the PCB to prevent the above issue and just to keep the PCB from backing off in general. Bumpons or shelf liner are great for this.
Related to above: if you have a floating PCB that's held on mainly by the switches (Helix, Lets Split, idk others too probably) DEFINITELY do the above 'upgrade'. It makes a world of difference, because the PCB actually stays on when inserting and removing switches lol. Just leave the 4 corners in when swapping switches, put the new ones in, and swap the corners last. Much easier to work with this way. I use bumpons for my Helix.