Sciencemadness Discussion Board

Non-oxidizing or corrosive lubricant for aluminum drilling

RogueRose - 24-10-2017 at 20:18

I have a lot of Al billots and ingots, and I need Al shavings, "swarf", powder and cuttings. My drill press works well with my tungsten carbide bits but it seems that I am going to need to add some kind of fluid to lubricate (and possibly cool) the cutting. I'm using 3/8 - .5" bits as well as stepped sheet metal bits that starts at 3/8" and ends at 1 3/8" - with each level increasing by 1/8". These are often used for hardened steel sheet metal and even cast iron, but they work find for Al (the ones I have do at least).

I'm wondering if there is some common fluid that I can use that will not effect the Al shavings, chips, etc. I would think water may oxidizer or cause other problems.

I do have old cooking oil (not sure content), I also have:
Liquid soap (100% coconut oil soap about 1:10 soap to water - could be watered down to strenghened)
Dish soaps ( Dawn, Palm olive and the like)
-coconut oil
-palm oil
-olive oil
-Saffllower oil
-Sunflower oil
-castor oil
-pork lard
-Beef Tallow
-Glycerol
-Motor oil - 10w30
-household 3-in-1 oil (not much left though)
-WD40
-Regular Diesel
-Biodiesel
-E85
-55-60% ethanol (rest is water)
-little mineral oil (best used for my beat bath though...)
-Ethylene glycol (pure concentrate anti-freeze - with stabilizers and other
-Windshield washer fluid

others that may be helpful
Na2CO3
NaHCO3
Borax
urea
TriSodium Phosphate

After the cutting is done, I'll have to strain the fluid, remove the chunks/shavings/powders so I can use the fluid again if possible. I'm just not sure how I can clean the shavings so that they don't have the oil on them or any residue, or have the Al react with any of this.

On a side note, I'm probably going to be doing the same thing with Mg slabs and probably Mg/Al slabs, but that won't be for a couple months.

Can anyone give any suggestions on which would be the best method to lubricate the drilling and not damage the Al shavings in any part of the process?

Much appreciate to anyone who can point me in a good direction for this. Thanks a lot and the best to ya'll!!

JJay - 24-10-2017 at 20:34

Cooling fluid isn't usually required for aluminum with a drill press, but you could probably use cutting oil (which is a fluoridated petroleum I believe). Compressed air and water might be options also.

Twospoons - 24-10-2017 at 21:21

I used kerosene regularly in the machine shop.

Fulmen - 24-10-2017 at 21:33

A good cooling liquid is quite beneficial when machining aluminium. It turns soft and "gummy" as heat builds up, this in turn will increase friction between the tooling, workpiece and chips. Chips can easily weld itself to the tooling or workpiece if left unchecked.

I mainly use oil dispersions as I have flood cooling on the lathe. Water also removes heat more effectively. Flood (or mist) cooling is obviously the most effective as it can remove more heat, but it also makes a mess. It's fine in a machine with a chip tray and water sump, not so nice on a drill press on a wooden work bench.

Almost any cutting fluid should help, the standard choice in machine shops used for most machining is a appr 4% oil emulsion in water. For aluminium straight mineral oils (like WD40 or CRC 556) are often used, some claim alcohol is the best for HSS tooling when a good finish is required. I guess it often boils down to personal preferences and availability/convenience.

There are also special cutting fluids (extreme pressure additives) based on sulfurized oils or chlorinated hydrocarbons. I make my own by heating rape seed oil with appr. 5% sulfur, it makes a huge difference for high-load operations like tapping and threading harder materials. But I don't think it will be necessary for drilling aluminium.

RogueRose - 24-10-2017 at 22:52

Thanks for the replies, I noticed someone said something about "It turns soft and "gummy" as heat builds up" - I'm wondering if some type of soap would work for this, like bar soap on the bit, or a diluted solution into the whole.

I'll just have to see how much it changes the A for the Final product. Thanks again!

bobm4360 - 25-10-2017 at 01:31

"A-9" from an industrial supply works with both Al and Mg, and cleans easily with methyl ethyl ketone or acetone. For cleaning chips, put 'em in a bucket or saucepan and wash 2 or 3 times by decantation. Both metals oxidize very quickly and will have a thin (molecular layer) oxide coat as soon as the metal is exposed to air. This layer stops further oxidation of Al; but Mg oxidizes quite a bit deeper.

[Edited on 25-10-2017 by bobm4360]

Fulmen - 25-10-2017 at 03:17

Soap could reduce friction, but so will lard or motor oil. And they would probably handle the high temperatures better. Reducing friction is only part of the solution anyway, as the cutting inevitably produces heat. I'm not sure if soap handles heat as well as lard or regular oil will, so you could end up with burning the soap causing more problems than it solves.

Bezaleel - 31-10-2017 at 08:41

Quote: Originally posted by RogueRose  
Thanks for the replies, I noticed someone said something about "It turns soft and "gummy" as heat builds up" - I'm wondering if some type of soap would work for this, like bar soap on the bit, or a diluted solution into the whole.

I'll just have to see how much it changes the A for the Final product. Thanks again!


Apart from "A-9", as bobm4360 mentions, there exist standard drilling fluids for light metals and copper. These both enhance cutting properties (which is what you want) and cool and lubricate. They are relatively expensive, though.

Another one that works for me is methylated spirits (just the cheap blue stuff). Obviously, if you take the cleaner white spirits (I assume this will also work) you won't have a minor amount of residue left on evaporation. For me, this worked surprisingly well when working with HSS drills in aluminium.

I advise you to stick to using lighter molecules, because the longer chains are more difficult to remove, rendering you aluminium unclean.

Sulaiman - 31-10-2017 at 09:04

Or possible alternatives;

Melt the aluminium and pour it into water to form smaller lumps
Use the lumps as is, or use a ball mill to pulverise them.

unionised - 31-10-2017 at 11:18

I'd use engine oil- because I have plenty and it will do the job.
Then I'd remove it with a lighter oil- maybe WD40.
If you need to, you can remove what's left with lighter fluid (carefully).
Alcohols risk reacting.

Bert - 31-10-2017 at 17:24

If you can disclose the purpose you have for these (flammable?) metal particles, it might help.