Overview of coolant use please

I have bought a small coolant tank/pump unit from Axminster, description here: http://www.axminster.co.uk/axminster-machine-coolant-system-102148?sel=102148

It felt a natural upgrade to general lathe work for (a) lubrication and (b) rinsing swarf away from the immeadiate cutting area.

I have read that water soluble oil is not good since any residue (being mainly water) will readily tarnish all the exposed steel surfaces on the machine. Apparently Cora B neat oil should be used instead. Is this incorrect advice; since I've read in other threads on this site that people do use water soluble oil?

I have a bottle of RDG 'Sarsol Whitewater' lying about already https://www.rdgtools.co.uk/acatalog/1L-High-Performance-Water-Soluble-Cutting-Oil-705756.html and would be shame not be able to use it.

Hopefully you can see why this conflicting advice leaves me unsure! Thanks in advance.

Edited By choochoo_baloo on 24/06/2017 22:09:07

A rule of thumb is use soluble oil for cooling with not much lubrication, and neat cutting oil for lubrication with not much cooling.

All my machines use soluble cutting oil. The oil remains behind after the water has evaporated; at least that's the theory. I suspect that the newer oils are less prone to cause staining. I can't really comment as most of my machine tools were in less than pristine condition when I acquired them so any staining isn't obvious.

I use coolant primarily when using carbon steel or HSS tooling, otherwise I cut dry. The only exception is the CNC mill where the 'coolant' is mainly used to wash the swarf away.

To get the best from soluble oils, and particularly to avoid too weak a mixture, which can cause rust, it is important to have the correct percentage of oil and water. I use a refractometer to check my coolant mix on a regular basis.

Andrew

I bought a bottle of ALUSOL following a recommendation on here. It is supposed to be for aluminium but the instructions state that it is also OK for other metals.

I use it at a lower than the recommended 20 to 1 dilution and have had no problems whatsoever with staining or rust either on MS or on the lathe.

Brian

I tend to cut dry most of the time; when I need any lubrication I dab some neat cutting oil onto the work, for cooling what small MS work I do I use a lab 'squirty' bottle that has a mix of soluble oil/ water with no signs of rusting on my lathe, for Aluminium a few squirts of WD40 suffices. I have made up a 'mist' system for use on my mill that runs off the compressor but have never had the need to use it in anger so far so can't comment on any residuals left

​George.

Choo Choo, my vote is for soluble cutting oil as well. You will find that the lathe/mill will dry off after using soluble oil, I have been using it in my Bantam for 30 or 40 years and have never noticed staining on any part of it, and would not worry much if I did see a stain. One hears this story over and over, and wonder if it has reached the status of an urban myth.

If you use oil it will get everywhere, and migrate to everything you touch and make a real mess, you will also throw half of what you buy away with your swarf, and it is not cheap. Cutting oil is used in high cutting load applications by industry using powerful machinery, our usual hobby machines do not really require it. I used to operate Sykes gear shapers using cutting oil which is one of the correct applications for it. At the end of the day my overalls stank of oil and so did my clothes underneath them. It did not matter how many wipers we used, one could not escape it. As you are probably aware there are potential health hazards from oil soaked overalls.

Chris Gunn

A significant potential problem with soluble oil based coolant is bacterial contamination.
You can get bacterial growth in the water based coolant that makes it go rancid, which is both unpleasant and a health hazard. Nice explanation here

**LINK**

I use neat oil in my lathe to avoid the hassle of managing soluble coolant, especially as it is infrequently used

I've been using soluble oils for the last 15 years. Coolant sits in my tanks for months, or years, at a time and I've never had a problem with nasty niffs or contamination. I suspect it's one of those things that was a problem in the past, but modern coolants are much better. However, the old tales persist.

Andrew

Good to hear Andrew, I must admit it did put me off using soluble oil when got my lathe.

I used to use Biokool14 from Hallett Oils. But they were taken over and it became more difficult to obtain. So, on the advice of a friend who is a professional machinist, I swapped to Castrol. After a search I chose Castrol XF as a good all round coolanf, including for grinding which is important for me.

Andrew

I know a bloke who converted his three lathes and one milling machine to using a 50/50 mix of automotive engine oil and kerosene for coolant. Seems to work well. Lubricates all the moving parts of the machines too. No corrosion. No staining. No going rancid and smelly in hot weather or if not used for long periods.

I thought ALUSOL was medical rear end treatment ?
BobH

I don't know that I would like to use this particular ALUSOL for that, perhaps you were thinking of ANUSOL?

By the way, ALUSOL is a Castrol Product specifically for aluminium but also suitable for many ferrous metals.

Brian

Edited By Brian Hutchings on 26/06/2017 12:49:40

I've actually got that problem in the undiluted oil, and filter the bacteria out before dilution. Generally have no problems with it after dilution, but try to avoid getting it on bare hands, even so. I drip the stuff on and usually use a take-away food pot to catch the drips after use (so they can be put back in the dripper). Never have more than 500cc of diluted cutting oil at any time.

Regards,

Richard.

I just take a 1 litre bottle to a local machine shop and buy soluble oil from their bulk tank. Never had a problem with it going off with our South of France summer heat. I don't know if it's specially formulated for the temperatures here.

Russell

When I bought my lathe [many moons ago ] I bought some Dromus oil from Shell,since this was the stuff we used in the machine shop where I worked. I found,to my surprise,that it stained and indeed rusted my machine. I took the matter up with Shell,but got got nowhere,they could not be bothered. I ended up getting another oil elsewhere which had anti rust built in and never had a problem since..I would not worry too much about a little staining,since the machine is intended to be used,not admired. Rust is a different matter,it,s like an unwelcome guest,it,s very difficult to get rid of,and always leaves it,s mark.

Remember,if your machines are always clean and shiny,you are not making much use of them ! Enjoy them .

Try telling that to Joe Noci .

I suspect many of the stories of smelly and rancid soluble oil come from industry, in my working experience, the drip tray was treated as a convenient waste bin, and cigarette ends were thrown in as a matter of course, together with the dregs of tea and crusts from sandwiches and any other sandwich filling that fell short of expectations. Other things found there way in too, no wonder the suds went off. I avoid all the above and the suds in my machinery does not smell at all.

Chris Gunn

I appreciate there's a danger of sounding sarcy but how exactly do you filter out the bacteria? Presumably a devilishy fine filter? Sorry - had to ask!!

Murray

HI choochoo baloo

The coolant system that you have listed is unlikely to be able to
pump neat cutting oil. I too bought from Axminster a coolant system
20 years ago which was similar to the one you have indicated and
tried to use with neat cutting oil , it failed and i sent it back .
I bought from them a better system that uses the more commonly
seen type of coolant pump seen here in the J&l advert and it worked.
To improve the flow rate the pipework mush be large enough to
place little restriction on the pump ,i use 15 mm copper tube and
the same bore plastic tube ,placement of the pump relative to the
work to keep the pipework of minimum length and keeping the
pumping head low will increase the flow rate.
I use neat cutting oil Excelcut 401 in 4 machines and Excelcut 433
in the Universal grinding machine ,they all use the same type of pump.
The J&L advantage adverts are from May last year but come around
often.
The sort of flow can be seen from this boring bar.

John

Edited By John Pace on 27/06/2017 14:28:15

I probably don't filter out all the bacteria, just the visible clumps. Do it with the usual method, a filter funnel & some filter paper (in my case, kitchen roll), and leave it to drip until about 25-50cc have dripped through into my 500cc washing up squirt bottle that I use for it. Given the bacterial loading, this can take some while as the paper becomes pretty well choked with the bacteria. Then I dilute by filling the container with tap water. Seems to work, and I never get further visible clump growth in the diluted coolant.

Dependant on the pore size in the paper & bacteria size, it may be that I'm getting out a very high percentage of the bacteria. Certainly the first couple of seconds of filtering are very fast compared to the rest.

Regards,

Richard.

Edited By richardandtracy on 27/06/2017 15:07:07