I was hoping for this to work but no luck. I used a fresh sweet corn cob from Tesco. I am specifying this to point out that the cob was rather fresh (hence was not dried up and hard). I tried this corn kerneler but with no luck. The blade teeth of this thing kept jamming on the cob. You need an immense amount of force to get it through the end which defies the initial logic of buying this thing to make your life easier. The process also becomes rather dangerous as the flimsy plastic bends around while you apply brutal force - was really worried if it actually fell apart in my hands and the blades cutting into my skin.
You cannot remove all the kernels from the cob as the thing can only go down to about 3-4cms from the bottom of the cob. Do not try lifting it and pulling or pushing the cob through with your fingers as the blades might cut you open. I eventually managed to unjam the cob out of the kerneler by pushing the top out of the gadget hence losing the bottom 3-4cms of kernel which I had to remove using the old, good and reliable traditional knife.
As you apply force to get the kernels out you will see a large paddle of yellow juice on your bench as this thing will crash most of the kernels it removed - so don't expect any juicy, flavoursome taste out of it as most of it is lost lying on your desktop. Unless you have a dishwasher I can see you struggling to clean it without cutting yourself.
Good idea, VERY poorly executed and can become dangerous....