n3xu5 said:
Just out of curiosity, does anyone here know what the cascade is lapped with?
Procedure is this:
Initially they are fly-cut flat, but moving to being ground flat for all future blocks. The fly-cut bases are not flat at all really (~50 micron variations), but the ground bases with a properly dressed grinding wheel produces flatness down to around 3 microns across the entire 80x50mm base - hence the switch to using this as the new first-step flatness method.
After the first-step flattening, the blocks are then finished off by hand using:
A polished flat marble slab
240-grit paper to remove gross non-flatness (240-grit won't be used with the future ground bases)
600-grit paper
Low-smell kerosene as a cutting agent.
I used to do a final dry (no kero) lap with the 600-grit all clogged up to get a fairly shiny finish which was reflective enough to shave with if you wanted, but I no longer do this on current blocks as I had too many complaints by people with too high expectations on receiving a perfect mirror finish, which was never my intention on producing, so I opted for a matte finish.
Now I just wet lap to 600-grit with the kerosene. This produces a matte finish to the surface that is vaguely reflective in that you can see your larger facial features (eyes, nose, mouth, etc) if you look at the base straight on, but you couldn't shave using it as a mirror.
I found that this finish produces the best results for me in my testing.
If one wanted a near mirror finish from my blocks, all they need to do is a follow up lap using 1000-grit, then 1500-grit, then 2000-grit paper. As Restorer points out above, doing this may actually be detrimental to thermal transfer performance in various scenarios, which is why I do not do this.