Patriqq, I apologise for my earlier post, but in all of it's simplicity in design it actually appears complicated in use.
you would have to complete all grinding on one side first, then take the knife out and turn it around. it would seem to me that if it's not put back in that clamp in the exact position in reverse...the grind may not be symmetrical because the angle is dependant on your platen.
it's also not stationary, it seems that the whole thing could get out of alignment while grinding by just hitting the platform with your foot.
it just seems like a lot going on verses just free handing them. I've never used a jig so I could be all wrong on this but the couple I've seen were articulating arms that reversed the blade while still in the fixture and were stationary like a rock.
No worries, it is a goofy looking thing that is awkward, especially because it goes limp when you let go (something I want to address with springs on future versions). As a throwing knife maker, I am often dismissed by the community so I'm sure some of that is coming out as defensiveness on my end. It isn't for everyone and I'm not expecting to please or impress all. I do, however, think it is perhaps/arguably the biggest innovation in knife grinding fixtures/jigs in decades in a world where 99% of knifemakers are making the same basic knife patterns with the same basic methods. There is little to no experimentation or innovation, especially in the area of knife making tech. As I mentioned above, my hope is to spark a little creativity and get some brains churning.
Those who freehand grind will never see the virtue of a jig; it is that simple. This includes me - I freehand the vast majority of my knives, and I could grind 3 of my standard knives in the time it takes me to get this jig to the grinder and set it up. I am using this for knives that are outside of my comfort zone (read above comments). I see this as a good way for a new knifemaker to learn how to freehand grind, or at least have a sense of intimacy that is close to the process of freehand grinding.
Your other points are valid concerns, and they are also directly addressed in the video - did you listen to the audio? It isn't a 10 minute video. In fact, the entire point of the video was to address these concerns. Precision dowel pins with mating precision reamed holes ensure perfect mirrored alignment when swapping sides (as explained in the vid). The time delay required to swap the knife around is no different than any other jig that clamps onto the knife, and the time can be improved by implementing a tool-less swapping method (as mentioned in the vid). Most importantly, the alignment isn't affected by moving the base plate due to the magic of the parallelogram (more info on that below) - again, this is discussed in the vid. There are a million ways one could terminate the bottom of the vertical rods; a base plate is just one. I started with the base plate because I wanted to test/prove the exact doubt you are expressing. The other virtue of the base plate is that the jig can be moved from machine to machine. This could be used in all kinds of machine work, not only knifemaking, and not only metalwork.
You are just like all of us - same as me before I started going down the road here - we have a pre-conceived notion that a jig must be rigid, when in fact all that matters is rigidity in the one axis that defines the bevel angle. Again, my intention here is to get people to rethink their pre-conceived notions.
Now it is important to understand that technically there is an error or discrepancy when the base plate is moved, and there is also an error inherent in the radial (as opposed to linear) motion of the jig. However, because the vertical rods are substantially long, the error is not noticeable/measurable. Another way to explain this is - imagine if the vertical rods were only 10" tall. In that case, the discrepancy would be magnified and noticeable. As the rods get longer, the discrepancy minimizes. If you were grinding a 36" sword blade, you would have some problems - which can be solved by either grinding sections of the blade at a time (i.e. moving the base plate) OR using longer vertical rods. Without moving the base plate, the vertical rods should be at least 4x longer than the length of the knife if that gives you and idea of what I mean here.