Thread: norton 4000 gritty and rough

I just received my 1st norton 4k/8k from craftsman studio.
I lapped it on a mirror with 3m 400 and 1000 grit wet/dry
the 8k side finished beautifully smooth, yet the 4k side feels like there is lots of gritty pebbles in the stone when I gently pass a razor down the surface. The razor is an old cheapy off ebay, it not very sharp, but has no visible nicks.

I've gone back 3 times to the 400 and 1000 and once back to a 220 grit regular sand paper. I've used a pencil multiple times to ensure that I am getting all of it off and flat. Each time I've wiped and rubbed the stone clean with my fingers and a sponge. I'm fairly certain it is not sandpaper grit that I am feeling. I can also find the high spots repeatedly with different parts of the blade.

I looked through the archives and only found one post similar that mentioned to lap off the factory surface, yet I don't seem to be getting anywhere.

any suggestions? Is that how it is supposed to feel? How much do I need to take off? what am I not doing correctly?
thanks
aaron