Lapping a tall heatsink

[megalomando]

Hi,

I have an OCZ Vindicator 120 which I'm trying to lap. I've done many small heatsinks but not a tall one like this is. I've tried to hold it steady as I lap but sometimes it rocks a bit. Each time it rocks, no matter how little, it digs at the outer edges of the heatsink.

While it looks like the center is OK, I really don't know if the "chatter" that happens with the rocking has in any way made the center non-flat.

I've looked around for suggestions on lapping these tall kinds of air coolers but haven't found anything on it yet.

Anyone have any ideas that work well?

Thanks

[it_burns_when_i_pee]

haha, fun isnt it

had the same lapping my TRUE, others report the same. takes a while but you got to get the pace and pressure right. circular motion worked for me, straight line it kept toppling.

oh also, keep the paper wet - it does help (a bit).

[davefr]

Hi,

I have an OCZ Vindicator 120 which I'm trying to lap. I've done many small heatsinks but not a tall one like this is. I've tried to hold it steady as I lap but sometimes it rocks a bit. Each time it rocks, no matter how little, it digs at the outer edges of the heatsink.

While it looks like the center is OK, I really don't know if the "chatter" that happens with the rocking has in any way made the center non-flat.

I've looked around for suggestions on lapping these tall kinds of air coolers but haven't found anything on it yet.

Anyone have any ideas that work well?

Thanks

Hold it as low as possible and wet the sandpaper with water and a drop of dish washing soap. Use whatever style of movement/speed eliminates the chatter.

[Clue69Less]

HWhile it looks like the center is OK, I really don't know if the "chatter" that happens with the rocking has in any way made the center non-flat.

I've looked around for suggestions on lapping these tall kinds of air coolers but haven't found anything on it yet.

Anyone have any ideas that work well?

Thanks

First off, anytime you hand lap, you will not end up with a flat prep. That's not necessarily a bad thing as long as you make it uniformly convex.

I used to have to hand grind, polish, lap, etc., large metal and ceramic parts. There are commercial devices available and the principle they work on is to rigidly hold the piece and then use outboard arms that bear on the work surface to keep the piece from tipping. It is probably not worth the effort to make something like that for your HS. But if you have access to a mill, you could do it. You need to be able to firmly clamp the base of the HS and leave access to the surface you're lapping. Then the piece you're clamping needs to have 3 or more arms that stick out a ways, at least 6" from the HS base. You could use little wheels or roller bearings to allow the whole rig to move around and the wheels would have to be height adjustable. You could spend 3 weeks making the jig and a half hour lapping your UE.

[STEvil]

If what I am lapping is unstable then I just move the lapping material (sandpaper, glass, etc) and hold the heatsink still.

[Clue69Less]

If what I am lapping is unstable then I just move the lapping material (sandpaper, glass, etc) and hold the heatsink still.

That can work as well as moving the HS manually, possibly a little better. You'll still get a convex prep but convex preps have been working for hand-lappers for a long time. The key is to focus on how you direct the pressure and keep it centered as best as you can. Practice on an old HSF first if possible.

[loonym]

If what I am lapping is unstable then I just move the lapping material (sandpaper, glass, etc) and hold the heatsink still.Absolutely. Very much like lapping the notoriously concave nvidia north bridges of old.

[SP1]

Have you tried Polymorph,it is a plastic that goes soft in hot water and hardens again as it cools.
You could mould it around above the base giving you something to hold with your hands.
Comes as small granules.