OH how I love my Victorinox Forester SAK. It has everything a resourceful and civilised gentleman should need in an Every Day Carry knife, such as a corkscrew. One thing that isn't quite great though is the quality of the steel used for the blade. Stainless steel looks good, but - for most types of SS - that's about it. Its edge is lost as soon as it gets good use. Carbon steel, however, holds a great edge for much longer. The other thing about the Victorinox blade is that the shape of the blade ("the grind") has a long taper with a secondary bevel - really I prefer short single bevels ("scandinavian grind" or "scandi" for short) which is personal taste but it is very easy to sharpen in the field.
I looked at other knives to see if there was anything out there with similar features to the Forester but with a carbon steel blade. Nope.
I looked out there to see if any clever cutlers are making retro-fit, aftermarket, Carbon-steel Scandi-grind Victorinox replacement blades. No such luck.
So, armed with some YouTube-learned metallurgy, and my Dad's garage (which is set up for metalworking, as opposed to mine which is set up for a band) - I hacked it.
This Instructable will work fine with most types of SAK although the method of mounting/hinging the blade and removing the scales might vary. If your SAK has a non-locking blade then the hack is MUCH easier since you don't need to worry as much about getting the "tang" exactly the same as the original - for the (locking) Victorinox Forester the tang has a "liner-lock" [wikipedia]
which means the tang has to be very accurate for the locking mechanism to work properly, if at all.