X2 IHS lapping - assistance needed

[-= rtz =-]

Im doing my first IHS lap on a 5000BE (i lapped heatsinks before,but never heatspreaders) and just wanna ask a few questions in hope they get answered by the lapping xperts I attached a pic to show u whats bothering me,as u can tell from the pic its the edges.I started off with 400 grit,i got all the nickel down untill there was only copper left.Then i kept going for a bit longer cause allready there i saw uneven scratches and the edges seemed non-flat.I kept going in one direction only without rotating by 90 degrees and i manage to got all the scratches even arround the entire base,even the edges.After i switched to 600 grit and continued with the rotating method the edges like in the picture came back,i think this is not normal.But i did check with a flat metal tool and it seems flat indeed in all directions and diagonals.I use a piece of glass from a picture frame on a desk,sand paper taped down flat,trying to use even pressure (3 fingers over the cpu).I just finished with the 800 grit.

1.Are these edges normal and will they go away on higher grits or not? If i need to repair them do i need to back to 400 grit again or can i use 600 or even 800?

2.Since im now on 800 grit and ive read that 800 is the sweetspot and higher grits are unnecessary,should I stop here or go for the higher grits? Im not a bling-bling type of guy and always go for efficiency (ghetto style) > looks

Any help would be greatly appreciated!

[Spawne32]

edges appear to be normal, and any grit is the sweet spot if you take into account the particle size of the thermal paste your using

[-= rtz =-]

K,but i still think the corners are NOT normal...if the surface is completely flat shouldnt the scratches all be even across the whole IHS surface?
I will try tommorow the method i used on 400 grit when i managed to get all scratches even,a bit harder pressure and lapping only in one direction without rotating.

[-= rtz =-]

I am now even more confused since I found 2 lapping guides,both had the scratches like mine,only one claimed that the corners are actually flat and that this is a trick of light (optical illusion? ) but the other said it ment the corners are concave.Id be very thankful to hear some more opinions on this,dont want to do an unnecessary re-lap which is possibly not needed at all and risk damaging the cpu.
Thx in advance

Spawne32,thx for your reply,I really appreciate it,Id just like to hear some more opinions if possible.

[Spawne32]

lol im telling you those corners are the result of hand lapping, it cant be stopped, and its perfectly normal