Back in the 60's I bought a 3 LINE SWATY from my barber. This stone had a Carborundum 118S companion stone to flatten the Swaty.
There were grooves along the side of the carborundum stone where spike points were removed so the barber would not cut the customer. This was very common practice.
I include a photo of the grooves. I don't know why this point removal is so hard to believe for some people. Razor knowledge was basically "word of mouth" until the internet came along in the 1990's.
Any info you have acquired in this modern technological age is a direct result of information shared by us old guys who got our knowledge prior to the electronic age. Pay attention to the old guys...:)