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New member and new in the hobby - from Calgary - hope to stick around and learn from you all
- Thread starter KalNovice
- Start date
Thanks. Nothing specific. I am currently just learning to tap aluminum heat sinks. I am thinking of transforming an old stand lamp into an LED 40W stand lamp. The LED lamp is a circular wafer that I will screw onto a large CPU heat sink. Then I will need to find a rod that I will thread to fit the stand light base plate and screw into the heat sink on the other side; of course after tapping it too 
Depending on the alloy (always a guessing game on some commercial items) aluminum swarf can gum & load the tap flutes. This can then translate into anything from so-so resultant threads to a stuck or even broken tap. Shallow or low thread or bigger threads aren't so bad. But the opposite (deeper holes, higher thread count & finer thread pitches) can be fussy. Some tips:
- tap should be very sharp & good condition. I prefer non-coated but its not as big a deal as it being sharp. If you do a lot of aluminum consider keeping some dedicated spiral type, they cost the same but perform better.
- do everything you can to stabilize the entry of the tapping operation so the tap enters concentric to the hole, at least the important initial part where threads are being cut. There is nothing wrong with hand tapping as long as you don't wander off axis much, both in & out
- ejecting aluminum chips on deeper holes / higher thread count can be fussy, so that usually means backing out the tap as necessary to clear chips & re-entering again. Personally I like the taps that eject swarf to the top of the hole vs. pushing out the bottom but its kind of application specific
- use a cutting fluid, something like Tapmatic aluminum or WD40 works quite well on aluminum
Good luck!
- tap should be very sharp & good condition. I prefer non-coated but its not as big a deal as it being sharp. If you do a lot of aluminum consider keeping some dedicated spiral type, they cost the same but perform better.
- do everything you can to stabilize the entry of the tapping operation so the tap enters concentric to the hole, at least the important initial part where threads are being cut. There is nothing wrong with hand tapping as long as you don't wander off axis much, both in & out
- ejecting aluminum chips on deeper holes / higher thread count can be fussy, so that usually means backing out the tap as necessary to clear chips & re-entering again. Personally I like the taps that eject swarf to the top of the hole vs. pushing out the bottom but its kind of application specific
- use a cutting fluid, something like Tapmatic aluminum or WD40 works quite well on aluminum
Good luck!
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Thanks for the tips Peter. I like the spiral bit.I already have a tapping set that is not the spiral type. I did use cutting fluid and was able to tap 1/4 of an inch #6-32. I wasn’t able to go deeper. The bit would rotate in the nut. I am not sure whether I should apply more force to tighten the nut ..
I used my drill press for a steady entry and drove the couple few turns by hand. Then I finished the job with the hand tool.
Anyways I do not need more than 1/4 “ and I got the wafer installed. I cut the #6-32 1/2” screws I had to 1/4 using a dremel with a diamond disk
Now looking for the right rod...
To be continued
I used my drill press for a steady entry and drove the couple few turns by hand. Then I finished the job with the hand tool.
Anyways I do not need more than 1/4 “ and I got the wafer installed. I cut the #6-32 1/2” screws I had to 1/4 using a dremel with a diamond disk
Now looking for the right rod...
To be continued
Attachments
I've heard good things about A9 cutting fluid too.
But is the heat sink you are showing in pics not copper (vs. aluminum). Or is that just the part that mounts to your aluminum work? Copper can be even more 'fun'. It's a very sticky material. Everything I said about aluminum X2. I find WD40 works pretty good for cutting but I haven't done much deep tapping thankfully.
Another process that might be considered for sticky materials is roll (form) tapping. There is no cutting involved to make threads, its kind of a distortion process. You need a special tap & different drill size pilot hole & it involves some other considerations. May or may not be suitable. Lots of info on the net.
http://www.practicalmachinist.com/vb/general/tapping-copper-231244/
https://www.cnczone.com/forums/general-metalwork-discussion/20322-cnc.html
But is the heat sink you are showing in pics not copper (vs. aluminum). Or is that just the part that mounts to your aluminum work? Copper can be even more 'fun'. It's a very sticky material. Everything I said about aluminum X2. I find WD40 works pretty good for cutting but I haven't done much deep tapping thankfully.
Another process that might be considered for sticky materials is roll (form) tapping. There is no cutting involved to make threads, its kind of a distortion process. You need a special tap & different drill size pilot hole & it involves some other considerations. May or may not be suitable. Lots of info on the net.
http://www.practicalmachinist.com/vb/general/tapping-copper-231244/
https://www.cnczone.com/forums/general-metalwork-discussion/20322-cnc.html