THIN cutting oil - Suds alternative?

Hi Forum

On my 2 day Axminster small lathe engineering course, we used soluble oil to assist drilling. I did ask about rust issues after use, but this didn't seem and issue, with the application of WD40 after a wipe down.

Now, I'm looking into this currently, to use with my even smaller Chester DB7 lathe, and yes, I'm concerned about staining / rust / wear.

I've searched the forums, and found solid answer, each preferring their own solution. I guess I'm looking for a neat, thin, coolant that doesn't cause any of the fore mentioned pitfalls.

I know WD40 isn't a lubricant, but what about GT85? That IS supposed to be a lubricant. Is there a product that anyone recommends that can be used as a coolant / cutting spray that can assist drilling (since that's what we used it for on the course)

Ta

Hi I have a rag which is soaked in slideway oil 68 and when I have finnished I give it a wipe all over gets rid of swarf, dust and I get no rust.

David

Thanks David. I do have slideway oil. I take it you use soluble then?

On my (rarely used) drill press and vertical mill I drill dry with one exception. On aluminium alloys I use a quick spray of WD40 to prevent the swarf from sticking to the tool. Nothing to do with cooling or lubrication.

On my lathes I use flood coolant when drilling with HSS drills, except for cast iron, brass and plastics. I run drills fairly hard and flood coolant is built into the machines so I use it.

For coolant I use Castrol Hysol XF, a multipurpose soluble oil. I use it for some turning, horizontal and CNC (but not vertical) milling and grinding. I don't care about staining, although it's not an issue. Rust simply isn't a problem, provided you keep the concentration in the correct range. As the water evaporates it leaves a film of oil. I don't understand how wear comes into it? Nasty niffs are reputed to be a problem with soluble oils. I've never had a problem even though the coolant sits in the tank for months, or years, being topped up as required.

Andrew

Edited By Andrew Johnston on 12/09/2019 10:04:41

Thanks Andrew,

Wear was mentioned in one of the threads on here... not sure of the date / forum, but it definitely mentioned wear. I thought exactly the same tbh. Maybe not cleaning the wipers? Not sure.

If I used soluble, it would be in a hand spray I think.

Hello Lainchby,

I think I can provide some reassurance on the vexed question of coolant staining.

I am currently restoring a Churchill Cub lathe made in 1947. When I took the headstock off the bed, the joint faces beneath had residues of old oil and looked very poor. A wipe with a rag, no more than that, swept all that mess away to leave perfectly smooth and clean ground surfaces, stained black by the effects of soluble oil that had crept into the joints after many years use.

The staining is clearly superficial, no more than microns in depth as on re-assembly it made no difference whatsoever to the location of or accuracy in re-positioning the headstock.

I conclude from all this that the staining which so many worry does no harm to the machine surfaces. Furthermore, this old machine had stood out in all weathers for some time after a factory closure, waiting for the dealer to collect; there was even water below the oil in the all geared headstock!

The rain had not penetrated into those joint surfaces other than just along one edge for maybe 1/8 of an inch and was no more than a slightly red mark.

I sweep my machines clear of swarf with a bannister brush after a machining session, it does a lot to keep them clean ready for the next job and only rarely wipe over with an oily rag.

I hope that story slays some dragons for you and perhaps others.

Brian

(Edited for punctuation)

Edited By Brian Wood on 12/09/2019 10:34:42

Cheers Brian

On steel, for turning/milling, I often cut it dry. Depends on circumstances.

If I feel I need to use a lubricant I am currently using Ambersil Tufcut, just because I have a bottle sitting around.

I also use 'Neatcut' (Google it).

I have a suspicion that Neatcut labelled up by various suppliers is nothing but ISO 32 hydraulic oil.

I have a very low general opinion of today's formulation of WD40.  Jack of all trades, master of none.  The lubricant content is a mere 5%.

It is, however useful as a lubricant for aluminium (as is paraffin, which is much cheaper).

I have GT85, but I use that as a mountain bike lubricant!

Basically, the more well known branded product, the more you will pay for it, and you don't need to.

Edited By David Standing 1 on 12/09/2019 10:53:00

Hi Lainchy, I use this as and when I need it on my Chester Conquest lathe and on my Cobra mini mill WD40 Specialist it doesn't seem to stain, but I'm not that worried about that, but I've not noticed any rust problems, even if I fail to wipe down afterwards. The Ambersil Tufcut that David S 1 mentions is also very good, especially for tapping holes and thread cutting with a hand die. If you go for the WD40 one, don't avoid getting it from that other well known outlet that sells similar items, as they charge just over £1.00 more.

Regards Nick.

Edited By Nicholas Farr on 12/09/2019 11:13:16

I use only pumped neat cutting oils for cutting and grinding
Exelcut 401 for turning and milling steel ,aluminium ,brass ,cast iron.
Excelcut 433 for grinding all of the same.
No rust problems ever, keeps the machines clean and oiled
I buy it from J& L the 401 is sometimes on offer in the Advantage flyer.
John

Cheers David.

I do have some Metacut CF that I do use for steel. I should have tried it on Aluminium I guess, but I did think it was more cutting, not coolant for drilling. I wonder if I could just thin it a bit with paraffin or white spirit for spraying in behind a drill bit?

The GT85 is from my bike shed also

...thanks also Nicholas and John. (I was replying and I've just seen your posts)

In my last place of employment, they used Dromos , or Dromus, not sure which spelling is right, so when I got my own lathe I began with that. Sad to say, I found that it caused rust to my lathe. I contacted Irish Shell about it and they agreed to send someone out to me to sort it out. Twenty years later, I.m still waiting !

I found a supplier in my local Farm Shop who sells a perfectly good soluble oil with an anti rust built in, for 28 Euro for 5 Litres. This mixes at about 20/1, so it goes a long way

I now get no rust problems no matter how long I use the coolant.

Have never used neat cutting oil, so cannot comment on that.

Why not? ISO 32 hydraulic oil is actually a good cheap general cutting lubricant for steel.

For a short while whilst doing a paid job i had to use some
Rocol V cut ss soluble coolant in the Myford, the photo here
shows the damage to the lathe bed that you can feel with
your finger tip not just the nail .I don't know if there was some interaction

between the cutting oil and the slideway oil that caused this .
I originally used the Rocol on the cylindrical grinder the continual
rusting problems with this have gone away with the neat grinding oil,
The rocol is now only used in the cut off bandsaw.

John

You can obviously use any oil as a cutting fluid but Neatcut et al are meant to be specially formulated for specific purposes, bit like putting cheapo oil from Wilko in your high performance racing spec car, it will run but for how long?

Tony

There are, of course, many different grades of hydraulic oil (including those used in aircraft control systems), but I suspect that a good grade hydraulic oil is probably a better spec that your average neatcut oil, not the other way round!

I'm with the those who lubricate sparely or dry. There's a flood cooling system on my milling machine but I don't use it much because of the mess. It is my least satisfactory tool purchase; pricey to buy and rarely switched on. The exception is hacking large lumps of steeI; then I pump neat cutting oil rather than emulsion because I fear - probably irrationally - that a water emulsion will cause rust. Repeat warning: flood is the operative word!

Neat cutting oil works as a dab-it-on lubricant, but I prefer the convenience of CT90, because it's much lighter and can be dripped or sprayed. For Aluminium, I use either WD40 or Paraffin, not because CT90 doesn't work but because it's more expensive. WD40 is handy because it comes in a spray can.

In the good old days before HSS it was vital to keep Carbon Steel cutters cool at all times and work had to be hosed continuously with emulsion. Although HSS less fussy, it still pays to keep it cool. The water in emulsion is excellent at absorbing heat and the oil improves finish. Another major benefit is washing swarf away from the cutting area. However, there are showers of disadvantages: early emulsions were a stinking biohazard; pipework, pumps, filters and tanks; mess; contaminated swarf and pollution. Although emulsions are still common, modern systems are more likely to use compressed air, aerosol mists, liquid gases, etc with a precisely aimed and metered high-pressure delivery system. It's unlikely that many hobbyists need anything like this sophistication - the amount of metal we cut and our low cutting rates don't justify special equipment. In practice good results can be achieved with sprays and brushes.

Never noticed any ill-effects myself but carbide is alleged to crack when thermally shocked. With carbide, it's best to either flood cool or not at all (Aluminium excepted).

Dave

I've mostly cut dry in the lathe and bandsaw, but use Trefolex CDT spray cans for most drilling and tapping. It does help with turning in the lathe but I've only found it necessary occasionally. It apparently leaves an anti-corrosive residue, but that might simply be one of the properties of the main constituents which are distillates of petroleum. It doesn't stain and does leave a more 'oily' residue than WD40 which I used on a friends milling machine to mill aluminium and zinc alloys. I've not tried anything else so can't make any comparisons.