Mini a's Up in SMOKE :eek: - Page 3

Mark A. Gulbrandsen · 16th October 2005, 06:48 PM

You can find the On-Semi PDF article below. I found it in less than 5 seconds with a google.

On-Semi Mounting/soldering article

Mark

anatech · 16th October 2005, 06:50 PM

Hi Mark,
Too late for that. The tap extractor broke off too. Once I get the darn things out I'll drill the hole larger and tap it for a big screw. After it's cut and sanded flat I'll drill and tap it for the original size. What a complete pain! It would have been cheaper to replace the heatsink.

I used a high speed steel tap, with oil. But they were blind holes with a #4 tap. My luck ran out on the 16th hole. Guess I was tired. Oh yeah, the tap is bottomed, but I guess you knew that.

-Chris

anatech · 16th October 2005, 06:52 PM

Thanks for posting the link Mark. I just download the articals and read them later.

This one should be read since it's basic knowledge.

-Chris

Mark A. Gulbrandsen · 16th October 2005, 06:53 PM

Yea 4/40 is a pain. Figure about 6 holes per tap... thats what I generally follow so taps don't break off. I still have a broken 2/56 in my VistaVision camera lens mount... I cringe when ever I think of it

.

Anodizing will also get rid of the extractor... extractors are pretty usless in that size.
Mark

anatech · 16th October 2005, 07:01 PM

Hi Mark,
Yes, I just bought the extractor. I also tried heating and cooling with it before the extractor broke.

I can normally get many more holes done with a tap (that one was new), I reverse often, back out and clean about three times a hole 3/8" deep. I am keeping the broken one to finish blind holes since it broke off square.

I have drilled around the broken bits already. Now I have some bits that taper. This just gets better and better. Thanks for your suggestions Mark, time for a new heatsink. I'll cut the damaged piece off so the rest can be used.

-Chris

LuckyLyndy · 16th October 2005, 07:12 PM

fcel wrote:

Quote:

I want some. Can I put my name on the list now, since I won't know when the KSA 50 groups are content.

We are never content!

Just ask Still4Given with his building TWO Krell Klones and now getting parts for his Pass XA build.
Those ceramics are ours. ALL ours! Bwwwaaaaaha!

I think we should all appear at Mark's doorstep on Halloween, with our
parts bags, chanting, "Tek or Treat!"
Lyndon

jleaman · 16th October 2005, 07:37 PM

Quote:

Originally posted by LuckyLyndy

I think we should all appear at Mark's doorstep on Halloween, with our
parts bags, chanting, "Tek or Treat!"
Lyndon

IM IN

mine will be the biggest.

Eric · 20th October 2005, 01:44 PM

Quote:

Originally posted by Mark A. Gulbrandsen
Lapping heatsinks so theya re flat is no big deal for a DIY'er but not practical in large scale manufacturing.

Mark

Hey Mark,
Could you please explain how you would lap the surface of the heatsink. I'm familiar with using lapping compound to install new valves into a lawnmower engine - you apply some lapping compound, put the new valve in the seat and use a "suction cup wand" to rotate the valve until it mates with the seat in the engine block.

What do you use to lap the surface of the heatsink?

Eric

anatech · 20th October 2005, 01:58 PM

Hi Erik,
It's as simple as using some wet / dry sandpaper and a flat surface. Start at 400 grit and use a sanding block to smooth out the imperfections. You can proceed to 600 after that. The heatsink is now far smoother than it was. It may even be flat.

I use titanium blocks, and you can get larger "stones" guarantied flat from metal shops. I once even had to get some heatsinks milled before I started the sanding process. They were bowed. Then I had to start at 320 grit to get rid of the tool marks.

There is one brand of amplifier I have to file first before sanding. They manufacturer is under the impression the one use silpads will fill the imperfections. -ahhh, no!

-Chris

Eric · 20th October 2005, 02:47 PM

Thanks for the details, Chris!

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16th October 2005, 06:48 PM	#21
Mark A. Gulbrandsen diyAudio Member Join Date: Sep 2001 Location: Salt Lake City	You can find the On-Semi PDF article below. I found it in less than 5 seconds with a google. On-Semi Mounting/soldering article Mark

16th October 2005, 06:50 PM	#22
anatech diyAudio Moderator Join Date: Jun 2004 Location: Georgetown, On	Hi Mark, Too late for that. The tap extractor broke off too. Once I get the darn things out I'll drill the hole larger and tap it for a big screw. After it's cut and sanded flat I'll drill and tap it for the original size. What a complete pain! It would have been cheaper to replace the heatsink. I used a high speed steel tap, with oil. But they were blind holes with a #4 tap. My luck ran out on the 16th hole. Guess I was tired. Oh yeah, the tap is bottomed, but I guess you knew that. -Chris

16th October 2005, 06:52 PM	#23
anatech diyAudio Moderator Join Date: Jun 2004 Location: Georgetown, On	Thanks for posting the link Mark. I just download the articals and read them later. This one should be read since it's basic knowledge. -Chris

16th October 2005, 06:53 PM	#24
Mark A. Gulbrandsen diyAudio Member Join Date: Sep 2001 Location: Salt Lake City	Yea 4/40 is a pain. Figure about 6 holes per tap... thats what I generally follow so taps don't break off. I still have a broken 2/56 in my VistaVision camera lens mount... I cringe when ever I think of it . Anodizing will also get rid of the extractor... extractors are pretty usless in that size. Mark

16th October 2005, 07:01 PM	#25
anatech diyAudio Moderator Join Date: Jun 2004 Location: Georgetown, On	Hi Mark, Yes, I just bought the extractor. I also tried heating and cooling with it before the extractor broke. I can normally get many more holes done with a tap (that one was new), I reverse often, back out and clean about three times a hole 3/8" deep. I am keeping the broken one to finish blind holes since it broke off square. I have drilled around the broken bits already. Now I have some bits that taper. This just gets better and better. Thanks for your suggestions Mark, time for a new heatsink. I'll cut the damaged piece off so the rest can be used. -Chris

20th October 2005, 01:58 PM	#29
anatech diyAudio Moderator Join Date: Jun 2004 Location: Georgetown, On	Hi Erik, It's as simple as using some wet / dry sandpaper and a flat surface. Start at 400 grit and use a sanding block to smooth out the imperfections. You can proceed to 600 after that. The heatsink is now far smoother than it was. It may even be flat. I use titanium blocks, and you can get larger "stones" guarantied flat from metal shops. I once even had to get some heatsinks milled before I started the sanding process. They were bowed. Then I had to start at 320 grit to get rid of the tool marks. There is one brand of amplifier I have to file first before sanding. They manufacturer is under the impression the one use silpads will fill the imperfections. -ahhh, no! -Chris

20th October 2005, 02:47 PM	#30
Eric diyAudio Member Join Date: Nov 2000 Location: Central PA, USA	Thanks for the details, Chris!