Drilling heatsink?

Big Perm

Big Perm

Budtender
Jg88 said:
I'm trying to make holes in this heatsink so I can mount bjb cob holder https://www.cdiweb.com/ProductDetail/MODULEDMEGA13450BHBG-MechaTronix/574066
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ouch. If it were me, I'd lay it out on the heatsink, mark your holes, ping a dent right where you want the hole to go with something sharp to make an indentation for the drill to ride in and not walk. Then drill a 1/8" hole where you need them. Put your cooling compound on and rivet it to the heatsink. Rivets and a rivet gun are cheap. If you do use this method, let me know and I'll help you before you pop the rivets in so you don't mess it up. I've riveted cobs before.
 
socaljoe

socaljoe

Cocaine Cowboy
Big Perm said:
They'll tap steel, so yes. Pilot hole is optional.
What you linked will work, and tap to the depth of the threads (the actual hole should be deeper).

What are you trying to do?
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Just throwing this out...aluminum tends to bind in a drilled hole where steel makes a nice chip and evacuates, so self tappers can be risky as they can bind and shear off.

@Jg88 personally, I'd go with a drilled and tapped hole. If you do go that route, there is a product called tap magic for aluminum that is really good stuff. Oh, and don't forget a tap handle, you'll snap the tap if you try to use pliers or vice grips. And one more note on tapping...don't force it, go clockwise a tad and back it off to break the chip and repeat... stay steady and straight with the tap, go slow and remember quarter turn clockwise half turn back.
 
Nugz

Nugz

Member
I just did these. I used a punch to make a dent then drilled a small hole and used small self tapping screws. Zoom in real close and you can see the screws in the COB mounts. It is a commercial 16g aluminum cookie sheet. The other one is an import retrofitted with quality COB's. I did the same thing with this one.
 

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Oreguhnism

Oreguhnism

Really Active Member
$50 drill press from Harbor freight has been priceless for hole drilling, lol.

Fancy bits for tapping blind M3 holes with 6/7 pitch isnt as important, unless your running production, but are still fun to play with.

Anyone know the size of a #43 drill bit? cant rember off the type of my head, my choice for pilot holes for self tapping m3's even for a few hundred or just a couple at a time.

And if your going the self tap way, remember that thread pitch can sometimes cause binding, which will bind most materials. It can be difficult because small drill bits at this size, dont often display thread pitch.
 
Jg88

Jg88

Active Member
Oreguhnism said:
$50 drill press from Harbor freight has been priceless for hole drilling, lol.

Fancy bits for tapping blind M3 holes with 6/7 pitch isnt as important, unless your running production, but are still fun to play with.

Anyone know the size of a #43 drill bit? cant rember off the type of my head, my choice for pilot holes for self tapping m3's even for a few hundred or just a couple at a time.

And if your going the self tap way, remember that thread pitch can sometimes cause binding, which will bind most materials. It can be difficult because small drill bits at this size, dont often display thread pitch.
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Which self tapping screws would be better for cobs
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Oreguhnism

Oreguhnism

Really Active Member
Jg88 said:
Which self tapping screws would be better for cobs
View attachment 56858
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Both look like pan heads, so either looks fine, although the dimensions are key ie length and the 2nd example looks to have smaller head diameter, fits more options.
Is the top one just a sheet metal screw?
I usually use 6mm long m3s with an allen head ie socket cap or pan heads with a 6/7 pitch. Ive mounted strips, cobs, etc
 
Oreguhnism

Oreguhnism

Really Active Member
Jg88 said:
Okay sweet I'll try those out, and for the pilot holes u said #43 drill bit right? Is this the oneView attachment 57051
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Bam, the exact one, hombre!
Also, shop around for those m3 screws, they can be had cheaper, just a good pic example fyi...
Also think you can use #44 and a #42.
44 is still undersize, I believe, but nearly equal to a m3 diameter. #42 will work as well, I just found it a wee bit tighter by hand. #43 is my fave.

But honestly, i know instances over on RIU, where people would not even drill pilot holes on straight aluminum, just start the screw right off. Its quicker and more dangerous to equipment, imho, but aluminum is softer than some types of wood, especially sink material ie 616x.....
 
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