Cooling on a lathe

You're right, heat was your problem, and it's nothing new to anyone that has done any close tolerance work. If you don't cool your parts to ambient temperature when trying for specific sizes, there's almost no way in hell you're going to have success. The larger the parts, the more difficult it becomes to hold size, I'm sure you can understand.

As long as you stick with commercially prepared coolants, rusting is not an issue. The big problem comes from tramp oils entering the coolant, leading to some pretty bad smells. If your machine lends itself to the idea, you can install a skimmer and aeration to the sump, which will help keep the coolant fresh for a longer period of time. If you can keep oil out of it, simply circulating it daily can be enough to keep it sweet if you start with a well cleaned and sanitized sump. That requires chemical cleaning, a simple flushing with water or solvent isn't enough to do the job. Check with your supply house for a sump cleaner.

Keeping coolant in any machine that uses it only occasionally is a tough job. It's a decision you'll have to weigh heavily. It's messy to use unless a machine is totally enclosed. Engine lathes are usually not. In order to use it successfully you'll almost have to have a backstop that wraps well above and over the chuck, and is the width of the chip pan, which will minimize the amount that sprays away. Should you choose to build one, make sure it drains back into the chip pan, and has a side on it that wraps around the headstock, directing anything wet back to the chip pan. That requires a little thought so it isn't in the way of the chuck and the related chuck cover that you'll likely have to build to keep spray from the chuck from covering you when running coolant. This cover can be hinged, or slide out of the way, over the headstock, when changing parts. It's best if it can be removed from the machine easily when not needed. Mine simply slides off, making it very useful. Pics available on demand.

When you balance the pros and cons, I strongly suggest you get set up to use coolant. There are times when it's really the only way to get a job done, such as drilling large, deep holes, or trying to do finish machining on roughed parts that are close tolerance. It spells not only faster work, but better success. All depends on how you think you're going to use the machine. If you intend to "turn manhole covers", cooling is likely to not be an issue. If your plan includes light or heavy production of parts, especially parts that demand close tolerance, it's not a luxury, it's mandatory.

Regards the spray idea, it's better than nothing, but pretty useless when drilling deep holes, and I'm certain there are other places when it might not be adequate, although nothing comes to mind at the moment. I have used spray on the rare occasion when it was up to the task.

Good luck with your decision~

Harold

Yep coolant is a mess on a manual lathe .After you rough turn your part let it cool down .I just take a damp rag and rap it around the part.

I find on some older lathes at work that a misting unit works really well, especially on the lathes with no provision for coolant,

also when doing close tolerance work I will try stop turning and let the part cool to room temperature with about two light passes left to make , then when the part is cooled down take a pass to get a good dimension and then your finish cut to size

no cute tag line available

Certain spray degreasers work fast to cool a part in the lathe with a burst of spray from the nozzle onto the part.

RJ

Thank you for all of the responses. I guess if I want the best cooling I can go flood and spray my shop. For a bit less cooling, use mist and breath the fog.

Does commercially prepared coolant include soluble oil that is added to water, I have some of that, or would I be better off with one of the newer miracle juices?

I've run machines that use soluble oil and can say with total honesty that I hate the damned stuff. The chemical coolants are far superior in cleanliness and feel. I don't care for the way soluble oil leaves machinery feeling. Sticky, almost dirty feeling, at least to me. YMMV.

Harold

The water will evaporate out of the soluble mix and leave behind a mix of oil & finings that can eventually restrict the passages intended for lubrication of the machine. I found the saddle on my lathe seemed rather dry once. Pulled it off and gave a thorough cleaning. I have only used straight cutting oil in that machine since then.

michael

For what its worth..I work on CNC machines for a living. Fixing, repairing etc etc. Most of which use water sol.

Every coolant tank in my home shop is filled with oil. And will always be.

Gunner

"To be civilized is to restrain the ability to commit mayhem. To be incapable of committing mayhem is not the mark of the civilized, merely the domesticated." - Trefor Thomas

Foor cooling without lube, you could use one of the cold-air jets, though I suspect they eat a lot of compressor capacity for the cooling delivered.

hard as you try if you use water soluable you will get tramp oil in it and wind up with a blob of jelly in the resivoir. Proper maintainence of water soluable is utmost important and 99% of the home shop and even commercial shops do not practice it like it should be done. Go with a strainght petroleum coolant and don't wory about it. Visit my website:

expressed are those of my wifes, I had no input whatsoever. Remove "nospam" from email addy.

Gunner, you'll be proud to know that we changed out the coolant pump and are using oil in the recently-acquired GT-75 Omni.

RJ

Running oil is extremely messy, especially if you run machines to capacity. It doesn't take long until everything in the room is oil covered. The greatest advantage is that it doesn't start stinking like water based coolants do. As a coolant, it's a distant second to water based solutions. As an aside, I don't think you'd be very happy with oil in a surface grinder, and running a surface grinder dry is less than an ideal solution.

Harold

Bravo! It will last a long time this way. How do you like it?

Any further questions or help, feel free to call me or drop me an email

Gunner

The two highest achievements of the human mind are the twin concepts of "loyalty" and "duty." Whenever these twin concepts fall into disrepute -- get out of there fast! You may possibly save yourself, but it is too late to save that society. It is doomed. " Lazarus Long

Love it so far. It was definitely a good machine for us to start on. I am well versed in DOS applications, and the screw machine supervisor is highly skilled in his knowledge of what he requires, and computer savvy, so it has gone pretty well. We are both gaining ground with G-code as we go. Upgraded to the latest software version on Wednesday. Thank you again for your helpful input.

P.S. You're definitely not in my killfile, as long as you label OT posts.

RJ

Actually my 6x18 surface grinder does run oil when I choose to turn on the pump.Hangsterfeurs grinding oil. Same stuff I run in my Covel 512 OD grinder. The Hardinge lathe is filled with Castrol High Sulfur. And the HLV-H has a tank full of something I dont recognize. Shrug.

I can live with the occasional bit of oil here and there. The guards keep most of it in the machines.

Gunner

The two highest achievements of the human mind are the twin concepts of "loyalty" and "duty." Whenever these twin concepts fall into disrepute -- get out of there fast! You may possibly save yourself, but it is too late to save that society. It is doomed. " Lazarus Long