Cutting fluid vs Thread fluid

[shtur]

Is cutting fluid that is used to cut threads on a barrel different than Tap fluid that is used to tap threads in a hole? There is cutting fluid for machinists and there is tap fluid for plumbers. Are they the same fluid?

[B R Shooter]

Cutting oil is high sulpher oil. Tapping fluid, such as "Tap Majic", is entirely different.

[BigEyeBob]

Is cutting fluid that is used to cut threads on a barrel different than Tap fluid that is used to tap threads in a hole? There is cutting fluid for machinists and there is tap fluid for plumbers. Are they the same fluid?

I use the machine cutting oil for tapping and machining on the lathe or mill .
For hand tapping I use a gel type lube called Trefolex ,a clear aromatic lube that smells a bit like a rubbing linament .Not sure if its available in the US.Tap Magic is reputed to be the ducks guts ,but is fairly expensive here in Aus.

[smokeywolf]

The type of cutting oil used is more dependent on the type of metal being machined.

If you're cutting threads at higher speeds with a machine, as opposed to low speed by hand, you do need a cutting fluid that will do a better job carrying heat away.

I usually use an oil with with a sulfur component, when working ferrous steels. When machining aluminum or brass I use Relton's A-9, Kerosene or a combination of the two. Crisco also works well for tapping soft, non-ferrous metals.

[country gent]

In aluminum the old stand by was lard. in summer time some shops really were "ripe" as the guys lard supplies went rancid. LOL. The old sulfar black oil is very good but finding true high sulfar oil is getting harder. The original tap magic is good reamers and taps cut very close to size with it. With it in stainless it discolors metals or stains. Most use more than is needed. The water sols are getting better all the time but if it sits to long it goes bad and gets nasty.

I prefer the old black oil, beeswax, and lard for tapping still. But I still have a pint can of white lead in my box for dead centers and steady rests. LOL

[bangerjim]

The cutting fluid I use is a water-based product that is pumped over the item being machined on the mill. It lubricates AND cools! Slo-speed thread cutting on my lathes is generally done with oil-based cutting fluids, depending on the alloy (Fe or Al based)

Tapping fluid is generally all oil -based and has various chemical additives depending whether Fe or Al based alloys are being worked.

Any of the stuff is dirt cheap! Buy both cutting fluids AND tapping fluids. You will not be sorry.

[55fairlane]

As a tool and die maker , please allow me to chime in

Coolent is a water soluble oil, minimum lube, mostly for carrying heat away from the work

Cutting oil, has sulphur in it, very good for lube but does not carry heat away

Tapping fluid is a host of different chemical compounds ment to applied to the cutting tool, not used as "flood coolent"

The better question here to me is A) what operation are you doing? Turning?milling?drilling? Tapping? B)what are you machining? C) is this a production or a one off operation?

Some other thoughts....don't use coolent on reamed holes, holes will come out under sized, don't use tapping fluid on reamers either, clogs the flutes, unless flood coolent (or oil) is used applying a little to the work surface can cause tool fracture, when I drill I use flood coolent (even applied from a squirt bottle) screw cutting or tapping I use dark cutting oil, reammimg a hole dark cutting oil, milling pockets, I fill the pocket with coolent, helps with chip removal and surface finish

Aaron

[Col4570]

Yes Trefolex is good for Tapping,even at High temperatures.Still got some left from my working days.The Trefolex we used was a Green coloured Grease and aromatic smelling.

[shtur]

Thanks everyone for the information. Aaron, thanks for the detailed explanation of different uses.

[EDG]

All the discrimination between cutting fluids and oils is pretty much a waste of time with non production machining.
If you are drilling, tapping and reaming millions of holes a month the choice can impact the cost of operations and tool life.
For a gunsmith the differences are minor and you might make the choice based on cleanliness and smell.

I ran production threading operations on a Landis threading machine with a 10" geometric type chaser type die head. The oil used was a very high sulfurized oil made by Oster.The smell was terrible and never came out of my clothes. I made custom 1/2" bolts by the 5 gallon bucket full. I also threaded 12 ft long pieces of 1/2" dia 304 stainless rod stock by the hundreds.

The rest of the shop used a red cutting oil in large lathes, Bullards, other VTLs and engine lathes. The red oil also stunk but it was used for single point threading on all the engine and tool room lathes.

Fast forward to the age of CNCs. Water soluble oil is mostly used now even for threading and power tapping on both CNC mills and lathes.

For low production or one at a time hand lotion with lanolin can often be used. It smells better and is easier on your hands.