Lapping a heatsink base

[Rubycon]

I know how it's done but I'm wondering when you do this are you holding the entire heatsink in your hand moving it over the sandpaper?

 

[Ika]

I held my Big Typhoon at the edges of the copper block at the bottom, so that the heatsink wouldn't tilt when I drew it over the sandpaper. If you hold it up higher, the friction might cause it to tilt, giving you rounded edges (which is probably not a good thing) or uneven pressure (which is generally a really bad thing).

 

[MadScientist]

If you put a bevel on the edges of the heatsink base first it will help keep the edge of the heatsink base from catching the sandpaper and tilting it over. There's lots of lapping guides on the net. This is one of the better ones. Link

 

[Tullphan]

Could one turn the HSF upside down & use a sanding block-type thing?
These monster HSF's are a ah heck to lap!

 

[ch33zw1z]

Originally posted by: Tullphan
Could one turn the HSF upside down & use a sanding block-type thing?
These monster HSF's are a ah heck to lap!

It doesn't seem there's a "perfect" way to do it. As long as the base comes out even, and you're satisfied with the look of things then it's all set.

 

[Rubycon]

Originally posted by: Tullphan
Could one turn the HSF upside down & use a sanding block-type thing?
These monster HSF's are a ah heck to lap!

That's what I thought. I'm in touch with a machinist and he's laughing at me explaining the lapping process. I am in the process of obtaining a few TRUE heatsinks and he said he would use a CMM machine to plot how flat the bases are. He said that is the first step to find out what it needed to make the base perfectly flat. FWIW

 

[Tullphan]

I was studying to be a machinist before I got the job I got now.
With the limited machinery I had access to, I don't know how i'd go about doing it.
Can't put it on a surface grinder...wouldn't secure to the base of it.
Can't put it in a mill...the vise would ruin the fins.
Of course, this was 18 years ago & the machinery was old then.
I'm sure there's better alternatives now.
Perhaps I need to make friends with a machinist. 😉

 

[Quiksilver]

Originally posted by: Tullphan
Could one turn the HSF upside down & use a sanding block-type thing?
These monster HSF's are a ah heck to lap!

I was wondering the same because I really don't want to have to hold my tuniq tower by the fins (the damned things are sharp) and somehow these top heavy heatsink doesn't seem like it would want to lap by holding that tiny copper block at the bottom (not too mention I would probably sand the tips of my fingers).

 

[DerwenArtos12]

I have an old(80+years) milling machine that is perfect for heatsink bases. It was designed and built by my great grandfather to be run on steam from the furnace in their house in illinois. it now runs off an electric motor with variable speeds. the actually milling head with whatever bit you want to use is actually fixed and a number of worm gears attached to wheels actually move the object your milling into the bit. The reason it's perfect for heatsinks is the way the vise is designed. It was originally designed and built to help my great grandfather machine parts for his 1/10 scale functional rail engine and the vise is less than 1/2 total size with hard rubber padding on it with a completely open underside. I haven't checked total clearance under the vise but, I know my xp-120 fit in it, just barely width wise but with a lot of room height wise.

 

[Tullphan]

Originally posted by: DerwenArtos12
I have an old(80+years) milling machine that is perfect for heatsink bases. It was designed and built by my great grandfather to be run on steam from the furnace in their house in illinois. it now runs off an electric motor with variable speeds. the actually milling head with whatever bit you want to use is actually fixed and a number of worm gears attached to wheels actually move the object your milling into the bit. The reason it's perfect for heatsinks is the way the vise is designed. It was originally designed and built to help my great grandfather machine parts for his 1/10 scale functional rail engine and the vise is less than 1/2 total size with hard rubber padding on it with a completely open underside. I haven't checked total clearance under the vise but, I know my xp-120 fit in it, just barely width wise but with a lot of room height wise.

Too bad you're not in IL...i'd pay you a visit & let you let that thing work its' magic! 🙂

 

[DerwenArtos12]

Originally posted by: Tullphan

Originally posted by: DerwenArtos12
I have an old(80+years) milling machine that is perfect for heatsink bases. It was designed and built by my great grandfather to be run on steam from the furnace in their house in illinois. it now runs off an electric motor with variable speeds. the actually milling head with whatever bit you want to use is actually fixed and a number of worm gears attached to wheels actually move the object your milling into the bit. The reason it's perfect for heatsinks is the way the vise is designed. It was originally designed and built to help my great grandfather machine parts for his 1/10 scale functional rail engine and the vise is less than 1/2 total size with hard rubber padding on it with a completely open underside. I haven't checked total clearance under the vise but, I know my xp-120 fit in it, just barely width wise but with a lot of room height wise.

Too bad you're not in IL...i'd pay you a visit & let you let that thing work its' magic! 🙂

Oh believe me, it's not magic, it's a hell of a lot of work and more than a little scary to use but, thats why it's fun. I swear I've run out of the machine shop yelling and swearing atleast once every time I use it. None of the moving parts, including the bit has any type of shielding around it at all. About 4 years ago I literally almost put out my eye and ended up rocking a pirate patch for about 2 months whilst using the lathe.

Actually, ironically enough, all the equipment was first built and run in Park Forest and these three things got dragged out to AZ when my family moved here in 63. More than half the shop was left behind in a basement up there, somewhere.

 

[Old Hippie]

It was originally designed and built to help my great grandfather machine parts for his 1/10 scale functional rail engine

Just a pic, or two?

I'll buy ya a :beer:.....or two.....or three...or......

 

[DerwenArtos12]

Originally posted by: Old Hippie

It was originally designed and built to help my great grandfather machine parts for his 1/10 scale functional rail engine

Just a pic, or two?

I'll buy ya a :beer:.....or two.....or three...or......

Yeah, I've got some pictures of pictures. One with my granpa and gramma riding it. I'll see if I can dig them up.