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View Full Version : Hi Ho I found myself stopping by, Lets talk coolant



cybor462
01-11-2009, 02:33 AM
Hi all.. I have been very busy and never seem to find the time to stop by. With my full time job vanishing early last year (linked to mortgage lending) I vowed to make my hobby/part time shop tool business full time.
I was not really ready, maybe I never would have been but here I am. Of course I only really do my own machine work so again I am dependent on the consumer directly. With this economy it is tough. Enough of the gloom now lets talk shop...

I was working today and actually amazed myself with a finding. No I did not invent anything new. It relates to process and fluids.

Quite some time ago I was in a discussion here about coolants, which ones were best, which to use and when. I am not here to debate that all again.

I am producing a new tool. It is 1018 CR 1 1/2" dia. Running it on my lathe doing facing, contouring with a form tool, drilling. I always was a firm user of syn. flood coolant, water based. I use flood coolant all the time. I saw a video some time ago where the user used oil, no flood.

I always thought why would you use oil if you had flood at your disposal. With this job I need a decent finish on the face and contour. I was not getting a good finish at all. I use sharp tooling, yes it is correct. I tried both carbide and HSS and still no go. I used flood with them all.

After getting disgusted I almost started to decide what additional step I would need to get that finish.

I decided to try oil.
To run down the discussion I had here about coolant, the consensus then was flood syn water based was the best. No bacteria or very little, no EPA issues and the list goes on.

I am now sold on oil. I have cheap Enco cutting oil I bought 4 gallons of the stuff a year or so ago. Used it on the mill mainly as I do not have flood setup on the mill. It worked ok but I do more aluminum on the mill so WD40 is the big gun there.

Today I machined these parts and as soon as I hit it with oil the facing, contouring, and drilling now went sweet. My finish is very good. No more ridges very smooth, a brushed satin finish. More than acceptable for this job. I tried the oil with HSS and carbide, gave me the same results. Drilling was easier. I do use parabolic drills for the deeper holes but there is no galling with oil and is goes much quicker.

Downside, it is messy, although for those that have a rust issue this will take care of that. I do not have trouble with rust. It sure makes a slippery mess of the machine. I need to learn to cut back a little, I do not flood it but I drip it. I think I can stretch it a bit more but Wow I am sold.

Any ideas? Am I just batty or is there some logic here.

The other discussion the main thought for coolant was to cool. No duh right! but there has to be a need for the oil for more than cooling. I am sure flood syn water based or water soluble oil would cool very well. Just by flooding it would carry the heat away. Oil seems to stick on the tool and work but it will heat up quickly so I feel it's heat dissipating properties can't exceed flood.

Just thought I would throw this up as I now wonder about this age long debate.

chief
01-11-2009, 04:15 AM
Flooding does not necessarily cool, the coolant needs to ramain in contact with the material long enough to pick up the heat before it travels away. The oil helps to allow the coolant to cling long enough to pick up the heat, it also help reduce rust in the coolant tank.
This is an endless debate, personally I make my own coolant, 2 parts water,
i part kerosene, 1 part mineral oil.
The way I have found to limit the mess is to make a funnel shaped spalsh guard from a plastic milk carton placed around the outside of the coolant
nozzle.

John Stevenson
01-11-2009, 06:07 AM
Chief,
What stops your mix from separating out again using water and non soluble oil ?

I use neat oil on a few of the machines, CVA lathe[ like a 10EE ] band saw, hobber but these are smallish machines.
The problem is with oil that to cool you need a good flow hence flood.
If you don't have this on larger cuts and drilling smoke is a serious issue.

I put my 14 x 40 on oil and had to swap back to soluble oil because of this. I can't run enough flood as it's a manual machine and has minimal guarding.

It is a pity as Klem has said I also get very good finishes on the CVA especially when threading and the oil takes care of a lot of the machines lubrication where the bed and saddle are concerned.

.

Boucher
01-11-2009, 07:57 AM
I went down this path several years ago when my lathe was located in a larger shop. It worked well but I could never control the mess. I went back to the water soluable type coolant. I have never had a problem with it spoiling or turning bad. (Knock on Wood) The last that I purchased was Rustlic WS 5050. I think it may be better than what I was using.

JoeFin
01-11-2009, 08:53 AM
Getting the perfect finish can be quite elusive.

1 particular piece of mystery metal I was turning was giving me a really hard time. I tried several types of tooling, carbide, HSS, insert tooling, until finally out of desperation I mounted a ¾ x ¾ shop ground HSS tool bit. (thought to myself “No Way”)

But the finish was perfect.

JCHannum
01-11-2009, 09:30 AM
Coolant and cutting lubricant can be two different functions performed by the same material. They can have different effects depending on the method of application as well as the different materials of the tooling and workpiece.

Just a suggestion, does the part necessarily need to be 1018? It is not the best material for surface finish. I am a proponent of 1144 and the leaded or sulfurized steels for free cutting and good surface finish. The initital cost is slightly higher, but the savings in machining time and exercises involved in getting a nice finish can quickly offset that.

cybor462
01-11-2009, 04:51 PM
Thanks guys for the insight. Let me ask a few questions to see if I got it.

Chief.. wouldn't flood always be in contact with the part. The flow is adjustable and if it is steady there is a steady contact just by shear volume of coolant across the tool and work. I do not run mine full out as my lathe is manual and as others mentioned the guards are not that great to contain the mess. With a reduced flow the contact is there. I think since it is circulating it helps cool the coolant so it is always much cooler than the tool or work at all times. I understand your point but I can't picture the difference to be that great to make such a difference with the finish.

But as my ex-friend always said, you do not know it all until your dead, and then you did not know enough to stay alive! Yep he is my ex-friend:o

JC no, using 1018 is for the cost as you eluded to. From what I found the difference in price for the 1018 and the 1144 is almost twice the cost. I am working on a tool that I maybe should not be bothering with. The final profit as is is real low. Paying more for steel would be a job killer.

I guess maybe therein lies the answer. :eek:

JCHannum
01-11-2009, 05:10 PM
It will depend, of course, on your metal supplier. But if Speedy Metals is any indication, 12L14 is cheaper than 1018. It will more than equal 1018 in all mechanical respects. It is not weldable however if that is a consideration.

http://www.speedymetals.com/

1018 $52.63 for a 6' length.
12L14 $43.27 for a 6' length.
1144 $74.25 for a 6' length.

A local supplier might price differently depending on the quantities involved, but price spread shoild be comparable.

bobw53
01-11-2009, 05:57 PM
Chief.. wouldn't flood always be in contact with the part. The flow is adjustable and if it is steady there is a steady contact just by shear volume of coolant across the tool and work. :

With coolant, for it to do its proper job of lubricating(high pressure additives), it needs to be where it needs to be, which is where there is the most heat, which is just behind the actual cutting edge, where the chip starts curling over.

In this area temperatures can easily approach 2000 degrees F, even you home shop guys with the little machines, there is an absolute buttload of heat in a very small area. Back to the coolant, with this type of heat being generated, obviously water based coolants will turn to steam and create a steam pocket. There is a reason for high pressure coolant(besides getting chips out of the way), it can break through that steam pocket and get the coolant to where it needs to be.

Of course coolant, even if it isn't getting to where it needs to be will keep your parts cool and take away heat from the whole system, not a bad thing when in a continuous cut on a lathe, since heat can build very easily, even if you are taking 80% of the heat out in the chip.

Going to oil probably gave you a better finish since it is able to get where it needs to be, not being pushed out by steam.