[alexccmeister]

Hi guys,

Very new to coolant and stuff. Just installed CNCfusion kit #4 on my X2 mill. Now I am looking into building an enclosure which I know how to do but as for flood coolant, instead of using the type used by alot of people here, can I use synthetic motor oil as coolant? Since its synthetic, it shouldn't smell after long use. Any reason why no one is using it?

I have read M oil is a good lubricating medium for cutting steel. Also in th epast when I was working in a hardware store, I have cut thread before with a theadcutting machine for water pipes. Old technology but we use a stream of oil for cutting the thread. Its messy but isn't the same with the other type of coolant? Thanks.

Alex

[cam1]

Hi: Motor oil is not formulated for metalworking applications. It's also very expensive and messy.You could start with a mist coolant sytstem (Noga for around $100), which uses compressed air/water/coolant. Just make sure to vent the fumes (cheap vacuum or suction fan with discharge going outside). The primary purpose of motor oil is to reduce friction on rolling and sliding surfaces. Metalworking coolants are designed to reduce friction, but primarily to cool the tool and to wash away the chips. Water is the best medium for cooling, and the oil is added to prevent rusting of the machine, and to reduce friction. Yes, motor oil can be used to thread pipe (it's better than nothing), but for heavy threadcutting, re-sulpherized oil is used, that just happens to look like motor oil.

regards

[alexccmeister]

Hi Cam1,

Thanks for your reply. The reason I am looking into oil as coolant is because I can't get the right coolant for milling job where I come from. I need to order online and I am sure custom here won't allow liquid to be shipped here.

When you say coolant, is this something similar to the coolant used for car radiator? Its antirust. I can mix that with water as well.

Thanks.

Alex

[cam1]

I suppose that could work, but the coolant I was referring to is cutting fluid that is a combination 97% water and 5% +/- soluble chemicals.
Let's see if someone else has any comments on using Automotive coolant.

regards

[alexccmeister]

Hi Cam1,

Thanks. Would love to know. I can get lots of these.

Alex

[AbsoluteZero]

The fumes from automotive coolant would be a lot to handle even with an exhaust. If you can't get metalworking fluid i suggest mineral oil. You can use it straight or with a air blast. I even have seen vegetable oil used to machine molds.

[budP]

Make your own
Use 18gal water---2gallons veg oil or corn oil---enough laundry soap to emulsify the mix

budP

[LeeWay]

I think straight water would be better than automotive coolant. The smell alone is enough reason not to use it. I tried it instead of Koolmist 77 for a very short time. 2 jobs. Then I cleaned it all out and went back to Koolmist. The best things about it is no smell or rust and it only takes a little. Mostly water.

Some automotive coolant is poisonous too. Best not to be used for machine coolant. I also noticed that it smoked. This tells me it wasn't cooling very well, but burning instead.

Whatever you chose to use, make sure you can't ignite it with a torch. I have seen some of my endmills glow bright red while being drenched with coolant. (Way too fast of a speed setting) A flammable source in this instance might just explode on you.

[alexccmeister]

Thanks guys. Will hear from more people and decide what to do next. I might end up looking for a source of coolant online and try to have teh stuff shipped here. Thanks.

Alex

[Geof]

If you are machining aluminum you can use automatic transmission fluid as a cutting fluid; this is Dexron (sp?) ATF. It works extremely well, just brush it on ahead of the tool.

When cutting steel a coolant/cutting fluid is not essential but sometimes it can help with getting good surface finish especially on manual machines. Try using ATF here, it may help a bit.

[alexccmeister]

If you are machining aluminum you can use automatic transmission fluid as a cutting fluid; this is Dexron (sp?) ATF. It works extremely well, just brush it on ahead of the tool.

When cutting steel a coolant/cutting fluid is not essential but sometimes it can help with getting good surface finish especially on manual machines. Try using ATF here, it may help a bit.

Hi Geof,

I am thinking of flood coolant with this stuff. I can get the stuff and use them over and over again. I can make a recirculating system for the coolant. I am surprise you are saying its not essential for coolant when cutting steel. I have always thought it more crucial to have coolant for cutting steel.

Alex

[LeeWay]

I think coolant or mist really helps out the hobbiest. It extends the tool life and speed error to some extent while also adding a touch of lube. With flood, it also helps remove chips from the cut path.

Coolant isn't required for mild steel. I milled many parts out by hand with only a drop of oil every few minutes. It got hot, but didn't effect the carbide tools much.

I have seen many video's on Youtube where no coolant is used on many different metals.

I personally use it for everything on the mill, just because it's there and I find it helps me from lack of experience.

[alexccmeister]

Hi Lee,

That is very interesting to learn. Can you explain its not necessary for mild steel as it is harder than aluminium.

I have tried milling steel before. The vibration and chatter I got from milling just a small DOC is scary. I was using HSS. I guess I should be using Carbide, shouldn't I?

Alex

[LeeWay]

Not necessarily. Chatter will kill a carbide end mill. Carbide is very hard, but fragile, because it is brittle. Cobalt will also break easily if you have lots of chatter.
HSS is the best choice if the machine isn't very rigid. Coolant will certainly help out with HSS. There are also lots of coatings that come on some HSS end mills. Some of these coatings greatly increase the tools heat limit. Close to that of cobalt in some cases I think.

If you are running a machine with lots of chatter, try to adjust it so that you have the least amount of that possible. Use the largest end mills you can and try to conventional cut more often than climb cut. Light cuts and slow would be your best bet even with coolant. Tool heating isn't likely going to be your main issue, but tool breakage will be.

[alexccmeister]

Thanks for the info. I try to adjust my gibs as tight as possible. Problem sometimes with X2 mill is that the gibs somehow loosen when milling due possibly to vibration. When I try to move the table from side to side, there is a lot more play than before. Not sure why.

Alex

[keebler303]

try some 'non permanent' threadlocker on the gib screws to keep em where you want.

Coolant is more important for aluminum as when it heats up a little bit, it likes to stick to the tool. Once you have a thin layer of aluminum built up on the tool, the rest starts sticking to it very easily. If you can keep the chips from sticking to the tool, you are in pretty good shape. With steel, you don't have to worry so much about the chips sticking so it is less important to use coolant. Just a quick squirt from time to time is plenty for normal cutting.

Matt

[Boots]

Motor Oil is designed for only one purpose and that is to lubricate. A lubricated tool does not cut well and will get dull quickly and soon snap under side presure. Use fluid designed to be used as a cutting oil not a LUBE oil. It is unsafe.

[alexccmeister]

Hi Guys,

Thanks for the info. Learned alot from the suggestions and comments. Will go with the light squirt and will also work on getting a mist or flood coolant from the internet.

BTW, regarding the loose gib screws. I think I have solved it. I use another nut to lock the first nut. So that sucker shouldn't come loose anymore. I did this for all my axes gibs screws. Now minimal play. Thanks.

Alex

[little bubba]

My two cents on this. A motor oil or lubricating oil is designed to inhibit metal to metal contact. A coolant or cutting oil is designed to promote metal to metal contact. One of the reasons you skim your sump, a lot of tramp oil/way oil in your coolant can effect your finishes and tool life. Cutting fluids also contain compounds that increase lubricity while there is metal to metal contact, such as sulfur or as in many flood coolants, chlorinated parafins. These actually mix with the metal you are cutting to create a very thin, very delicate very short lived coating similar to a TiN,TiCN or TiAlN coating on your tool.

As for the running steel dry, when turning, yes, run it wet. When milling you are in an interrupted cut. Carbide can take the heat, lots and lots and lots of it. It can't take the thermal cycling that coolant will put it under. Ever seen a hot coffee pot crack when cold water was put in it? Imagine that happening 3000 times a minute but with a much larger swing of temperature.

In a cut you can easily generate temperatures approaching 2000 degrees F. TiAlN or AlTiN coatings don't get hard and slippery until they are over 1700 degrees. So, a 1600 degree F swing a few thousand times a minute, I'd be pretty mad and explode also.

As for the floppy machines, don't discount carbide, variable helix/flute geometries are fantastic on floppy machines, probably more important than on a high dollar rigid 10k lb machine, they break up the harmonics that kill a floppy machine.

The trick is to stay with smaller diameters (cheaper), and load the machine in one direction to limit the floppyness. When profiling think deep and narrow, don't forget chip thinning and the higher feeds, load the machine up to the side so it won't bounce around, it will stay tweaked up during your heavy cuts and not cause so many problems. When slotting, ramp, load up the Z.