As already explained, the extractor pins are removed down (out bottom of slide), and installed upward, from the bottom of the slide).
Some thoughts remembered from the days of being a 3rd gen armorer ...
Since the pins were installed by a press, they can be VERY difficult to remove the first time. In the armorer classes they had students use a modified tapered 'starter' punch, to start the pin moving downward. The tip was modified (filed by students, if need be) to fit inside the top of the hole without peening it and wallowing it out.
It often took beating on the top of the pins with a 4oz ballpeen hammer (instead of a 2oz one) to break the pins loose. Once the pin was started moving, then a straight 1/16" pin punch was used to move it out the bottom.
We were told in some of the older armorer classes to remain aware of the orientation of the pin when removed, meaning the top and the bottom. It was explained it would make it easier to reinstall the tapered pin in the original orientation, since the slightly smaller tapered 'top' would go back in the top of the hole more easily than the wider 'bottom' of the pin.
Keep in mind that while the extractor
pin is being removed, the extractor
spring is still pushing strongly against the inside of the extractor.
It wasn't unusual for armorers to accumulate one or two more 'starter' punches if the narrow 1/16" pin punch tips were bent when the extractor spring pushed the extractor outward, as the extractor pin cleared the top half of the extractor.
A bent 1/16" pin shaft could be snapped off, and the remaining narrow, tapered base 'tip' becomes a new 'starter' punch.
There are 2 holes in the slide for the extractor pin. This is because the pin hole is separated by the space where the extractor sits, essentially making a top hole and a bottom hole. As someone else mentioned, the older pins were pretty much tapered, due to the top hole being a bit tighter than the bottom.
Armorers were actually given a tapered needle reamer tool, to use to lightly clean up the inside of the holes, inserted from the bottom of the slide (tapered point going in from the bottom of the hole). The older machining, and press used to install the pins, could leave behind some bits of shavings. Too aggressive of a use of the reamer could wallow out the hole, though, so it wasn't something done without care and attention.
Naturally, keeping pressure against the side of the extractor during reassembly was important, since you didn't want to have the extractor shift and cause the pin to hammer against the sides of the extractor's pin hole, peening the edges. Or, have she extractor shift before the pin makes it to the top hole (above the extractor), and then have the top of the pin hammered against the bottom of the top hole, off-center, so to speak.
We usually positioned the slides against the classroom tables we were using, with the simple wooden wedges used to hold the bottom of the slides off the table (so a pin wasn't driven down into a table surface
). Reversing the slide was a bit more of a task, since the rounded edges could allow the slide to tip. You learned how to use the side of your palm to keep the slide from tipping, while installing the pin - and holding the extractor depressed inside the recess - and using a ballpeen hammer and the flat end of a pin punch to fully seat the pin. Yes, it seems like it's a 3-handed task the first few times while learning to do it.
Any clean-up of burrs left behind in the slide rail under the pin was done with one end the S&W cylinder & hand window file, since it fit inside the slide rail. Carefully.
In later machining revisions the bottom of the extractor pin seat was relieved a bit, sitting/raised just a little higher than the rest of the slide rail, and a nicely sized flat end of a punch could finish seating the pin upward, back into the slide (like a Starrett punch).
To give you an idea of the learning curve sometimes involved, in the S&W classes they usually gave student armorers a separate 'extractor' and 'sight' gun, because they knew that gun would likely suffer more abuse. In my first class they gave each student 7 pistols to use for learning, one of which was the 'sight' & 'extractor' gun. Slides could get a bit mangled around the extractor pin holes and the sight dovetails.
In subsequent classes they started giving us just 1 pistol for sight/extractor training, and then 1 other for the rest of the repair/parts fitting techniques being taught.
I think in my last class we just got 1 pistol for everything. We were told that the increasingly refined machining and closer tolerances made things easier for the armorers, and the sale of sight pushers didn't hurt, either. The later kits didn't have the needle reamers for the extractor pin holes, either. Also, no more having to beat like the wrath of God on the end of a brass drift rod to break free front and rear sights.
FWIW, I never got the list, but I was told that just before the 3rd gen guns were about to become obsolete, the factory had been getting ready to release a list for armorers of the model-appropriate roll pins that could replace the solid extractor pins. I should've called and gotten the list, dammit, but I had a lifetime supply of the solid extractor pins I'd ordered by that time.