I'm going to try my hand on some 80% lowers tonight.  Is WD40 a decent cutting fluid or do I need something else?

If its no good, what do you recommend I can get at homedepot/lowes/menards?

Thanks

It works just fine for aluminum.  Kerosene as well.

It may work, but WD-40 is actually a poor lubricant.  Either of those stores carry better options.

Kerosen for aluminum.

Even the cheap lamp oil kero is better then wd40

WD40 is fine. Kerosene, mineral oil, light cutting oil. I don't like to use pure kerosene as it'll fling off easily. You can mix it with the other 2 listed oils though.


WD40 works great on Aluminum. You can get very good surface finishes using it.
Why didn't you at least recommend OP a product?

Great on copper / brass / SS as well, IME.

Is 'nt WD40 mostly kerosene anyway?

Kerosene works fine for machining aluminum on manual machines.

I would suggest an undiluted petroleum or mineral-oil based fluid.  Pure vegetable oil or lard oil would be better than WD-40, even kerosene as mentioned.  

I like water based cutting fluid.  Not as messy.

I’ve even used isopropyl alcohol as coolant / cutting fluid on lathe for finish passes on aluminum.

Go to Walmart, or 99cent store and get the cheapest motor oil you can find.

At the same time, get a really small paint brush.....and a bigger paint brush.

Then use the small brush to brush the oil onto the tool, and onto the part as you go.

Use the large brush to help remove the chips....or use a wet/dry type vacuum to suck the chips away from your work as you go.

Blowing them with an air gun just spreads them around....and makes more of a mess.


At this point you'll wish you ordered some water based coolant (you just mix it with some water) from Amazon, and use a heavy duty spray bottle to apply it as you go.

It will be an easier clean-up.



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Thanks for all the replies.  I think I'll find a water based one and go with that.

On lathe turning aluminum it works nice but it will smoke on heavy cuts .

If you're set up for it; water soluble oil in the coolant spray works best for lubrication and cooling.
What you want to make sure of is that the chips don't stick to the cutter. They'll gouge the surface if the cutter is gummed up;
or plug up the flute face of an end mill so it doesn't cut at all; especially if you're using a non-center cutting end mill.
Keep a scribe or small pick handy to dislodge any that have welded themselves on.

Not a machinist, but when I want to drill on the  trailers I use PD Blaster or Mobil One.   The drill bits last so it must be ding SOME good.

When you're cutting holes with bits, take the sharpness out of the tip by lightly filing 90° perpendicular to the cutting edge because this will keep your bit from grabbing the aluminum and not torque on the piece. Your goal is to take the sharpness down rather than ruining it's ability to cut.
There's information on Google if you search things like: "how to drill brass(not aluminum)" as this is a trick brass cutters use and it applies to aluminum very well.

Also, ruin the bit's cutting surface where it doesn't matter or else you run the risk of cutting your jig's inserts, which will cause non-centered holes.

When drilling aluminum, use moderate to heavy pressure and slower speed. Be on the lowest speed setting and throttle the trigger until you find the best low speed. You should get aluminum coils instead of shavings if you're drilling correctly.
Moderate to heavy pressure and low speed.

Don't be in a hurry to mill. Take more passes w/ less depth instead of fewer passes with more depth.

Use a face shield, or eye pro at minimum.
Use a disposable rain coat so chips don't stick to your clothes.
Have a vacuum nearby.
Don't expect this to take just one day.
Go slow and have fun with it.

If your safety detent isn't reaching in enough, take a drill bit by hand and clear any chips/burrs from it's channel. Sometimes, you may have to drill that hole slightly deeper. Be careful, the hole uses two sizes, as I recall. O could be wrong here but think I am right.

I buy WD-40 by the gallon jug to use as cutting fluid for aluminum.  No ragrets.