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  • How does a Machine Designer pick an oil?

    So exact a science is this, machine designers selecting what oils should be used? I suppose at some intellectual level it comes down to engineering, psi and all that, but there seems such variance. I mean is the design, pounds per square inch on bearing ways, size and fit of the gears, type of bearing used, etc, that much different than other mills in this size? Yet the oils vary quite a bit from machine to machine -32, 50, 68 and mine 90w.

    My Elliot calls for Vitrea 37 which near as I can figure is the same as a 100 ISO or about 90w gear or hydraulic oil . It's prescribes throughout - gearbox, ways etc. Perhaps in a gear box there's engineering to be done, but the ways? how much different can they be between other machines in the same class?

    its a @#[email protected]# to find, so i think I'm going with 68, but it just got thinking as to how much rhyme or reason there is to the specified oil??

    John S, what are you using in the Victoria?
    in Toronto Ontario - where are you?

  • #2
    I took a class in lubrication theory years ago.

    The one thing I still remember is the instructor saying to use the thinnest oil that the seals or configuration will contain.

    Comment


    • #3
      It aint rocket science. Oil is oil and even the wrong oil is better than no oil. I stock 4 oils and 3 greases and these fulfil 99% of my lubricating requirements. Get hold of a good cross ref fror lubricants modern and historical. Learn what lubes are generally used f[r what purpose. After you build a little discration about lubricants and lubrication you can wing it.

      Oh, your question: how does an engineer pick an oil? His outfit usually has a 4 lube policy too and a cross index. As for brand: safe assumption - he specs the brand whose rep last bought him lunch.
      Last edited by Forrest Addy; 05-23-2009, 10:09 PM.

      Comment


      • #4
        I learned a valuable lesson about oil last week.

        I usually oil the ways and leadscrews after cleaning up my machines. This time I noticed I was out of 30 wt oil that I normally use. But I had some Amzoil 5W30 synthetic oil from a recent oil change in my car. So, I poured some of the synthetic into my oil can and lubed everything up real good.

        Well, since I got busy with something else for about a week, I forgot about the synthetic.
        When I went to machine a part on my lathe, I noticed the handles were silky smooth, but the cut was terrible. I resharpened the M2AL tool bit I was using and tried again. Still the finish was bad...and the handwheels were creeping.
        WTF?? I tried carbide, still lousy. But, I noticed the crossfeed handle was actually creeping while making a cut.
        The synthetic oil! I got out a can of "Brake cleaner" and sloshed down all of the ways, lead screws, and feed gears. After the cleaner dried, I re-oiled everything with plain 'ol 30 wt oil. The next pass was almost mirror finish...
        Could it actually be the synthetic oil?
        No good deed goes unpunished.

        Comment


        • #5
          i use 30 w non detergent in my gear box and my ways and every where else on the thing and yes i can get a mirror finsih as well , i been using the 30 w on my hole lathe sence the day i bought it , and i wont change, way oil is BS ,its another exuse to spend money...even busy bee told me the 30 w was the better choice even though my book says 10w ,, the 30 w it runs smoother and quieter and i get great results...i have also started to do more dry turning as well and finding iam also getting better results as well on alot of the stuff iam doing,, where before well it was a challange,,

          fake oil is just that its fake and no good fr nothing and its very bad for your car as well..

          people that know what the hell is dip stick is use real oil and we have less engine problems then thoes using fake oil, its fake its gota be good is the way they think sad to say on the same note thoes that know what the dip stick is also us fake oil and they have more problems over time as well then thoies that know the dip stick and use real oil..

          some guy ask me to put fake oil in his car or any engin he has itell home go else where and get riped off iam and honest guy,,

          then they are like what are you saying,, well go put vegtable oil in it, it will last about as long well maybe not but you get the idea guys. ok

          not every thing you read is true or LAW ,

          my son use to belive everything he read and thougt of it as its the only way it is and thats it well he learnd different now,,

          my x wife calls me up, iam the computer expert here, also the most trusted , any how, she has this problem with her printer , tell me she called the place and they did this and did and still its half dead and wont print but it scanns so its half alive i tell her call back ask to talk to someone that has a brain in there head , the daughter board is shot 5 other people say no its the software, well not if you did a freash realod and all the drivers are in and you ahve also tested other devices onthe USB ports and they check out , ok morons ok thats what they are over paid morons and they want to give her a 300 dollar bill to have it looked at buy someone else they gave up on her , and blame the software, dummies got no brain in there head and call them selfs computer technitions that ar IT certified and trained well.. any one with half a brain cell would know its a 3 in one printer scanner fax and it runs indpendent boards on one main board in this case and it can stil runsome features if the others are down aka blown , the tech there dont even know the product they sold her ..

          get the idea here,, not trying to hi jack the thread but just show and example
          which also further shows not to belive everything you read its not always LAW whats in the books or what people say..

          use quaker state motor oil its the best , well same crap as tech 2000 from walmart at 2 times the price ..
          auctually its worse and still more expensive but thats another story,,

          use the 30 w on your ways, its not a problem and its not a hi precision million dollar machine that must have it ,,

          anyhow on that note good nite and happy machining

          Comment


          • #6
            Wow, just... Wow.

            I use pretty much just Iso 32 and 68 in my machines. I buy it in big 5 gallon buckets from Napa.

            I have opened machines and found all sorts of crap in them. There is no way I would put automotive gear oil in anything critical. Its specifications are not highly controlled, and it smells like a rotting swamp... Iso 100 oil is less than half the viscosity of 90W gear oil (middle of the road spec, 90W can be anywhere from ~125cST to ~300cST at 40°C. Iso 100 has a spec of ~90-~110cST at 40°.

            If I am not mistaken, the "Iso" oils are graded according to their viscosity. I use Iso 32 in oil baths, and Iso 68 on sliding surfaces.

            If you manage to decipher the recommended oils on any old machine, you will typically find that they match to any of the commonly available ISO xxx hydraulic oils.

            Later,
            Jason

            Comment


            • #7
              thanks for the replies, as to how designers select oils, i guess I'm still in dark but Forrest I think nailed how they select brand. I guess its less finicky than say how a violin maker selects his wood (which can come down to which side of the tree the sun was on).

              As to what I need, Jaso, your post made me realize how ignorant i am of viscosity. I'd erroneously assumed the the "number" was viscosity not realized motor and gear oil were completely different series....ie the "80w" on the gear oil scale is NOT thicker than 30 on the motor oil scale.



              The Shell Vitrea 37 i can't find, but i've found lots of other Vitrea oils.....http://www.shell.com/static/au-en/do...properties.pdf
              the Vitrea number is always the ISO number. So if what i read, that Vitrea 37=iso 100 is wrong and its in fact its ISO 37 I need....wow that's a much lighter oil than I'd been thinking...10-20w on the motor oil scale. does that seem right?

              are hydraulic oils graded on the same scale as motor oils, ie would an 10 or 20w hydraulic oil equate to an ISO 37?

              thanks
              Last edited by Mcgyver; 05-24-2009, 09:42 AM.
              in Toronto Ontario - where are you?

              Comment


              • #8
                I have never personally seen a hydraulic oil, sold as such, that was graded in the "wt" measurement. The stuff I buy is mobile brand ISO 68 and ISO 32 hydraulic fluid. Even the tractor supply who sells "universal hydraulic and transmission oil" doesn't grade it in the "wt" scale.

                I think the important part is to get as close to the recommended viscosity as possible, and to use an oil w/o detergents, friction modifiers, and other stuff intended to be used in IC engines.

                You can blend the oils to arrive at the needed viscosity, it would probably be much easier to go to the local farm store and buy a gallon of ISO 68 and 32 and blend to get your 37 cST variety then it would be to hunt for someone who is still producing it.

                Later,
                Jason

                Comment


                • #9
                  There is a Shell Tellus Oil T 37, listed on page 7 of your linked document, and it is indeed 37 cSt oil...

                  Good Luck,
                  Jason

                  Comment


                  • #10
                    Now I'm curious. What exactly is "fake" oil??

                    Also, what is a "hole" lathe??

                    Comment


                    • #11
                      Well, I know not to use synthetic oil on the moving parts of my machine tools, but....for automotive use, I beg to differ.

                      Sitting in my driveway is an eight year old car, with over 100K on it. After a break-in on conventional motor oil, I started using Amzoil 5w30 pure synthetic. The car picked up 2mpg when I switched over, and is tight and free of leaks. It uses no oil between changes (I usually change the oil @ 16,000 mile intervals) When it's ready to be changed, the oil is as clear and clean as it was when I first put it in. I'm a retired mechanic with over 40 years of experience, so I should know where a dipstick is. I've seen and had to repair sludged up engines (from paraffin based oil, AKA Penzoil)

                      Next time you board a jetliner to take a trip, look out at the wing. See that jet engine hanging out there? Probably cost $1.2 million. If you had to pay for it, you'd want the best oil, right? ALL jet engines use synthetic oil for lubrication, always have, always will. "Turbine oil" is all pure synthetic...And, if you knew anything about your "fake" oils, you'd know the original founder of Amzoil created the original formula by blending conventional and turbine oil together, eventually settling on full synthetic.
                      If you don't believe me...go to the Amzoil web site and look at the International diesel engine they took out of a school bus that ran for 275,000miles without changing the oil (the oil was Amzoil). NO measurable wear.
                      No good deed goes unpunished.

                      Comment


                      • #12
                        Originally posted by Forrest Addy
                        It aint rocket science. Oil is oil and even the wrong oil is better than no oil. I stock 4 oils and 3 greases and these fulfil 99% of my lubricating requirements. Get hold of a good cross ref fror lubricants modern and historical. Learn what lubes are generally used f[r what purpose. After you build a little discration about lubricants and lubrication you can wing it.

                        Oh, your question: how does an engineer pick an oil? His outfit usually has a 4 lube policy too and a cross index. As for brand: safe assumption - he specs the brand whose rep last bought him lunch.

                        Great answer. I suspect that the design engineers rely more on experience than anything else. If you have been designing lathes for 35 years, you pick up some knowledge about what works and what doesn't. Observation of the problems, complaints from customers, problems solved, etc. Forrest alludes to this.

                        And don't discount the free lunch thing. I have learned a lot at such things and a brand preferance can last a long time even in the presence of the the sure knowledge that other brands are equally good. I think you tend to have more confidence in a company that takes the time and effort to contact you personally.
                        Paul A.
                        SE Texas

                        Make it fit.
                        You can't win and there IS a penalty for trying!

                        Comment


                        • #13
                          Motor oil should not be used in a machine tool. It's designed to hold debris and water in suspension until the oil filter can remove the debris and the heat of the engine can drive off the moisture. In a machine tool you want the debris to precipitate out and you don't want it to hold water. You don't want the fine grit to stay in the oil and keep getting on the gears, etc..

                          Try this: Get two glass jars. Put motor oil in one and machine tool gear oil in the other. Put very fine grit and water into each. Shake the jars. Let them sit for a week.

                          Cal

                          Comment


                          • #14
                            Originally posted by Cheeseking
                            Now I'm curious. What exactly is "fake" oil??

                            Also, what is a "hole" lathe??
                            Synthetic.
                            One that is used for making a hole, using the whole machine.

                            Give the guy a break, he may,or may not be typing in a second language, give him the benefit of the doubt.

                            Comment


                            • #15
                              Originally posted by jacampb2

                              I There is no way I would put automotive gear oil in anything critical. Its specifications are not highly controlled, and it smells like a rotting swamp...
                              Jason
                              Thats interesting, so what do you run in your car gearbox (if its a manual trans)?
                              Think about it. An automotive gearbox is pretty critical, has to handle a lot more power than your average HSM machine (Don't know about the torque) Has to handle extremes of temp, vibration, uneven loading and general abuse from a variety of drivers, yet generally, most gearboxes seem to survive for a lot of distance using automotive gear oil.

                              bollie7

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