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Flood coolant/cutting oil options

MyLilMule

Hot Rolled
Joined
Jan 5, 2021
Location
Ohio, USA
Getting further along in getting my 2HL back together. Looking for options for flood coolant/cutting oil.

I should note that the mill is in my home hobby shop and won't get used daily, weekly or sometimes monthly.

My current thoughts are to stay away from water based coolants. I have heard from other K&T owners on the yootoobs that water based coolants in these machines are a bad idea since they can hide rust in places not easily accessed.

A friend suggested Ridgid Nu-Clear Threading Oil. It'd be about $175 for a 5 gallon bucket.

Looking for other options to make a better informed decision.

TIA
 
Some pretty good threads and an article here on PM:









I saw another one more recently, but cant find it atm.
 
We ran Mobilmet "Gamma" for years in the screw-machines and kept it well filtered. No complaints other than it's messy if you don't pay attention to flow and pressure, lots of the first and not much of the second.
 
Some pretty good threads and an article here on PM:









I saw another one more recently, but cant find it atm.
That's a lot of reading.
 
I thought this was an interesting quote from one of the threads.

Blame me I am a chemist that actually formulates coolants and cutting oils.
I run cutting oil in my machines at home, low maintance, high lubricity But
then I try to run dry whenever I can.

Coolants (water mix metalworking fluids) are need for high speed CNC machine
tools where cooling the part and the tool are of primary importance, water
based coolant will provide higher productivity in 90-95% of production machining.
If you are a manual machine user, my suggestion is stick with a good cutting oil.
 
I run flood habcool on my American 12" and both mills. Higher speed ops will splash it around which does make a mess, so I also use it in a pump oil can for smaller ops including tapping and threading. As flood, its fantastic for slitting saws, follower rest ops ie where lubricity and chip evacuation are important. Works fine for faster ops, but tends to be messy once it starts flinging- the improvment in finish and tool life is worth some effort but sooner or later the mess becomes too much.

I have a.length of conveyor belt material to drape over the lathe guard, to help capture chips and oil flinging off the lathe chuck.. at that point its tending towards diminishing returns.
 
First question would be: what type of water quality are you going to be using? The better the water quality the fewer hidden issues. Buy a premium coolant and use good water, and you should be good to go for months, even with intermittent use.

Straight oil, because it lacks water, is more forgiving. But you will want to make sure the pump can handle the viscosity of the oil. Most coolants have an effective viscosity of 1-3 cSt at 40C. Most good cutting oils will be in the 15cSt to 50cSt range. If your pump isn't rated for these viscosities, it will struggle and put unneeded energy into the oil in the form of heat.

For you K&T, something in the 22-24cSt range would be good for the type of work you would do. If you plan on running copper, brass, bronze, etc., then you should avoid oils with ACTIVE sulfur. Looks for copper corrosion scores of 1a and 1b to be safe. If not running yellow metals, or aluminum alloys with copper, then active sulfurs would be safe. If you want something multi-pupose, I would seek something with inactive sulfur and/or clorinated paraffins/olefins. This will give you broad performance over a range of materials and tooling.
 
Something in the MobilMet 42x series. I use 426 when I use straight oil flood.
This might be the front runner. Works for all metals and isn't all that expensive.

 








 
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