View Full Version : Mini-Mill / Router - Cutting Fluid??

22-02-2016, 09:23 AM
Hi all,

I'm building a mini-mill / router for aluminium mainly but also wood and plastics so its a multi-purpose build.

What are the recommendations for cutting fluid on aluminium??

On the Bridgeport while making the parts I'm using WD40 but its messy and not that cheap.

I see I have a few choices -

Manual spray bottle/can
Mist spray nozzle
Flood coolant

As the time taken can be considerable I think manual squirt bottle is out.

I have read about mist but the fogger ones have a bad rep due to breathing the fog, the coarse droplet misters seem better but what do you run in them?

Then there is good old flood, I used to use it on the lathe once but damn that was messy :) Again what sort of fluid is good for fine slotting and pocketing in aluminium?

I am building the machine with coolant in mind so all choices are possible at this stage, its only a small machine - 350x500mm bed area.

So far i'm leaning to flood coolant but not sure what type or if something else is better, compressed air clears the chips but makes a big mess and does nothing to stop it gumming the flutes up on the tool.

22-02-2016, 10:03 AM
Paraffin for cutting Ally

22-02-2016, 10:06 AM
Mist or flood??

22-02-2016, 04:30 PM
better to wait for someone that's running a mill setup to advise here, the guys with the high speed spindles tend to spray but also use air to remove the chips to prevent double cutting and fusion to the cutter.
Someone will be along to advise.

22-02-2016, 04:44 PM
Odour less Mist is best for Ali. I just use WD type De watering fluid I sell in my day job which is basicly paraffin type fluid.

Air is the key with Ali you want all chips blasted out of there before they get recut and overheat. Mess is just part of the cutting I'm afraid. The trick is lessening it but you'll have to accept some mess.!

22-02-2016, 06:50 PM
I know about the mess, the Bridgeport is dripping in WD at the moment and buried in a pile of chips :) at least it won't rust.

Probably not an issue on the mini-mill but I find the WD smokes a bit when hogging ally on the bridgeport, proves that the cutter is getting hot and that a squirt of WD is not enough, but as i said, that was a 14mm cutter, balls deep, cutting a pocket.

JAZZ, what fluid do you sell (if allowed to mention) and I presume thats the course droplet type of misting system?

Agree with the chip re-cutting, easiest way to bugger a bit is to let the chips pile up in the slot or hole, always when you don't have a spare bit ;)

22-02-2016, 07:33 PM
JAZZ, what fluid do you sell (if allowed to mention) and I presume thats the course droplet type of misting system?

Yes suppose could call it course drop let. There's very little fluid left so not messy and same goes for smoke. You'll also be cutting a lot faster with smaller cutters on the small machine.

The fluid is an industrial grade Maintenance spray I have made for me. It's basicly just Kerosene based fluid. I also have proper cutting fluid but much prefer this on ali. Unfortunatly being Kerosene based not something I think would be cost affective to send via courier else I'd offer.

22-02-2016, 07:42 PM

I have just read on a US group that a mix of Kerosene/Paraffin & ATF works, I'll have a go with anything that works ;)

There are a lot of simple mister units on the 'bay, for what they cost it's worth trying one out on the bridgeport I think.

Boyan Silyavski
23-02-2016, 01:25 PM
Recently i started using pure virgin cold pressed high quality Olive oil for everything and greatly recommend it.

All started as a friend of mine bought 5l from the cold pressed olive oil in a market, but did not like that particular taste. And as we always have 5l bottle at home, so i did not need it,so instead of throwing it away i took some for the MIG welder as i was dipping the tip in machine oil and had to use respirator for the fumes. It worked perfectly. No respirator needed now. I use it also on metal instead of ceramic weld splatter protector. Just brush table and parts in oil . Then i needed to thread 800 holes, so i gave it a try and it worked better than the threading oil.

Come on. I was genuinely surprised. It works for drilling and machining too. Also for preserving metal parts. Though i still apply it manually. Just the other day we were discussing how to mix it with water and use it in the mist system.

So if anybody has some ideas how to achieve homogeneous mixture and how much water and what about rust? I simply dont have the time these days to experiment on that. Though near seaside steel treated with said oil holds against rust very well. And i surely have rust problems living 300m from sea.

One thing that i guarantee you, is that it will be good for your hands, and it works perfectly on level with fine special purpose threading and cutting oils.Its not related but people quench in it and it works as well as a good quenching oil.

Note should be taken that i use the real deal-100% cold pressed oil, as i live in Spain. Not to speak of that the price is just a bit more per L than kerosene. Now i ask my self, why my hands were ever in a machine oil all day :stupid:


23-02-2016, 02:19 PM
The pressurised pot style of mister would likely work ok, may need a little more pressure but no problem once it hits the airstream at the nozzle.

No water needed, just air and oil.

Might be worth a try.