Recommended Cutting Fluids for Aluminum (50/60 series alloys)

Hey Everybody,

What cutting fluids/lubricants do you use when cutting 5050 & 6061 aluminum alloys?
I have tried dry-cutting, but obviously prefer the benefits of cutting with oil.

What are some good sources to pick up cutting oil? I am in the GTA (Canada). Does anybody run a coolant stream or fog buster?

Thanks for your input!

My plan is to run a mister/fogger style system with 100% IPA.

Probably similar to this: Low cost IPA mist cooling/lubrication system for cutting metals on my AVID CNC router - YouTube

I run mostly wood, so I don’t want oil getting all over everything and IPA works pretty well as a cutting fluid.

Thanks for the link. I will definitely have to take a closer look at this!

I’ve been using Tap Magic with very good results. I’m on my first bottle of it, but I will probably buy more when I run out.

If you use oil or cutting fluid (vs a mister with IPA), you might want to use a piece of 1/8" tempered hardboard on top of your spoilboard. You can pin it into place with a pin nailer, brads or staples. That way any overspray or excess oil will be captured by the hardboard and not soak into the MDF spoilboard. You can hold your material down using blue tape/superglue or double-sided tape.

When you’re done, just pop a flat paint scraper or other wide blade and lever off the hardboard. It’ll come off easily leaving your spoilboard unspoiled :slight_smile:

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I use WD40 when using my lathe and milling machine. I have done some aluminum in the OF but did it dry.


Thanks Bill. I have heard of TAP Magic before and people seem to like it!

Yes, WD-40 always works in a pinch! Been there, done that all too often :joy:

Hi Jim,

Thanks for the tip! I actually have an HDPE wasteboard with T-nuts so the oil is not a problem. I started off using the double-sided tape method, but now that my wasteboard is finished, I mainly use cam-style clamps in combination with some machining parallels.


@jarrfarr would love to see a pic of your HDPE wasteboard!

I worked as a machinist in Aerospace. We were only allowed to use coconut oil or griddle fry made from coconut oil. It is nontoxic and safe to breathe. Cutting oils were banned from the shop. Cutting oils will soak into the grans of the metal and come out in zero G’s was another reason. Coconut oil is easy to clean.


For sure. I’m working on a detailed post about our machine setup at school. For now, here are a couple of pics! Hammering 256 T-nuts was fun!!!


WOW! That’s perfect, as we are in a high school machine shop. I saw a lot of products containing chlorine and some other nasty stuff and didn’t want to use those products. We have a few ounces of “legit” cutting oil in the shop, but I think we will switch to a natural/safe alternative when that stuff runs out.

Very nice, love it!! Thanks for posting the pics!


Did those tee nuts cause the board to flex? Looks like your holes were just right but wondering about the displacement due to the nibs being buried in the non-compressible material?

Hey Alphonse, there is no flex whatsoever. The T-nuts are 2" apart and the holes are only 1/4" in diameter, We used a 3/4" sheet, secured with 6 bolts through the bottom of our table, so it’s pretty solid. The T-nuts bit in nicely to the HDPE.


Hey Jarrfarr,

meanwhile you could have milled away the top surface of this wasteboard. Did you have difficulties with milling it? What were the cutting parameters you used?

I did in fact surface the board once it was installed and bolted firmly.
If I recall, it was around ~120IPM, with a 1.25in surfacing bit. It wasn’t really a proper surfacing bit, but I used what I had. If you run into chip welding or long swirls coming off, run a slotting operation perpendicular to the surfacing tool path (this interruption will break the chips/swarf).

BTW, I milled the pockets and bores first, removed the wasteboard, hammered in the T-nuts, flipped it, then installed the board to surface it.


Hey jarrfarr,

thank you for the tip and for the cutting information!