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Ball Bearings

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  • #16
    Long WB 30's GP chassis - laser cut front & rear sections joined with SS wire + a laser cut rattle pan. One of the drivers behind the experiment - I don't want a visible front axle where one should not be and it is my belief that independently rotating front wheels are an advantage. I have gone the upright + stub axle route before. The combination of a steel stub in an aluminum wheel seems to wear pretty quickly leading to independent wobbling front wheels. an alternative would be to sleeve the wheel with a bit of brass tubing but that still leaves the problem of a retainer that needs to be hidden behind the wire spoke detail. It's all still in the cut-and-try stage. I'll post the results when there are some.



    • #17
      EM, I am also looking into installing ball bearings on the front wheels. But I am planning to 3D print my own front wheels. (Also my own front tires!) I'll sand everything round on my benchtop mill.

      Like you, I am still trying to come up with a good way to retain everything. I am considering designing a snap-fit for the ball bearing into the front wheel. Alternately a press-fit. But there are other options.

      Eventually when I stop noodling with ideas and try something I'll report back.

      Ed Bianchi
      Last edited by HO RacePro; 02-11-2020, 05:56 AM.


      • #18
        RevoSlot cars have ball bearings on the front axle, but not on the wheels themselves. I prefer to have independently rotating front wheels. If you use low grip front tires or coat the tires with superglue, etc. using ball bearings might be less important. Sometimes we do things to our cars to improve their performance that in fact have little or no effect. A person might be doing a complicated and/or expensive modification to his cars without getting any benefit, so some track testing would be in order.


        • #19
          Rich, you know I am always trying new things. And far more times than not I am disappointed, or at least underwhelmed.

          Somehow that doesn't discourage me. Every so often something works. That's enough to keep me going.

          Ed Bianchi


          • #20
            While I was still doing research I knew that people were often repeating work that had already been done, sometimes years before and by their own company. At one time my company had a large library staff with people that were good at doing literature searches. A literature search might include patents, trade publications, academic papers and the company's own internal publications. In their infinite wisdom the bean counters eliminated the library staff and the guys in the lab were left to fend for themselves. As a result of that policy there were a number of projects that went on for some time and cost a lot of money before they got killed because someone already had a patent in that area.
            I spent much of my career doing process improvement work and that tended to yield few patents because process patents are difficult to enforce. You do not want to hand the competition a blueprint for a better process, so often those are kept as a trade secret.
            In the slot racing hobby a similar situation exists. People that are really serious racers may share some basic information, but are not always eager to disclose every tuning trick that they know.


            • #21
              HO Race Not sure what type of cars you are building?
              Sealed bearings do have more drag and will slow the car.
              There are many grades of bearings and the amount of friction varies from one class to another. Precision Spindle Bearings are the lowest friction precision bearings and are used in very high speed applications like Lazer Type setters, dentist drills etc.
              EM I have been using bearings in the BWA Front Wheels of my VRAA and Tasman cars for some years, to provide independent rotation. Only had one failure and that was a cheap poor bearing, the Loctite never failed.


              • #22
                I learned that the first company I worked for out of college would give new engineers development projects that had been worked on before and never caught fire. Not as stupid as it sounds...

                - There was always a chance new eyes could discover a workable design
                - Advances in manufacturing methods, materials and technology might make a solution practical that had not been before
                - The market and/or competition may have changed enough to make a solution economic that had not been before
                - At worst it provided hands-on training in a non-critical project -- a project where past efforts were documented and could be used for instruction

                In point of fact all of the above might happen.

                Revisiting old ideas is not always a waste of time and resources.


                I'll tell you a secret. Someone fresh out of college can be dumber than sh*t when it comes to anything practical. I've met electrical engineering students who have never picked up a soldering iron and mechanical engineering students that have never spun a wrench. Keeping them corralled in a safe little sandbox until they learn up from down is only good sense.

                I earned my undergraduate degree at an engineering school that had a co-op program. Was famous for it. Still is. After my first 9 months in school I spent 6 months in industry, another 6 months in school, and traded off until I graduated with two years worth of actual engineering experience in real-world companies. I had made most of my newbie mistakes and was actually worth something to the company that hired me on day one.

                I should also mention I graduated with money in the bank. Never had to borrow a dime. Back then a co-op student could earn enough on the job to pay for his education, plus a little.

                Why the frick isn't that possible now?!?

                Ed Bianchi


                • #23
                  Because, in most places, engineering schools are part of a larger university and everyone has to pay their fair share of the cost of all the touchy-feely deans, associate deans, assistant deans, advisors, counsellors, special officers, etc. etc. that are "needed" in the academic world these days. In addition, there is the requirement for the creation of sufficient "..........Studies" departments to balance the politically incorrect tendency of STEM curricula to rely on objective outcomes.


                  • #24
                    STEM - Science, Technology, Engineering, Mathematics.

                    Engineering is the profession that has the most immediate impact on human society. At their best, engineers take discoveries in science, technology and mathematics and use them to create things that benefit people.

                    So, engineer as hero?

                    Can be.

                    The engineer is uniquely positioned to shape how new discoveries impact society. In doing so they must advocate for -- something. Financiers, managers, marketers and politicians need to understand what is possible, and what the consequences might be.

                    At their worst, engineers develop whatever they are hired to do, uncritically. And that can have dire consequences.

                    But engineers can push back. No, they cannot dictate what can be done. But yes, they can influence what is pursued.

                    I do believe it is important that young engineers acquire a broad appreciation for the consequences of their work. I feel it is every bit as important as understanding the more traditional costs -- material and labor.

                    For there are costs that historically have been ignored. At one time engineers were taught that air and water are free. They are not. And there are many other costs that society must bear -- some we have only lately come to appreciate. Some can be measured in money. Some in human suffering. And it would be arrogant to say that we now understand them all.

                    No education is capable of fully preparing any professional for the challenges they will face in their career. The best that can be hoped is that they are introduced to most of them, to the extent that they will recognize a challenge when they face it, and have some idea of what can and should be done. Knowing full well how likely it is that they'll need to study up and consult before taking the actions needed.

                    Sorry to divert the discussion. I return you now to your regularly scheduled thread.

                    Ed Bianchi


                    • #25
                      Not an engineer by training - sort of a "pepper tree" engineer by necessity. The most valuable course that I took in High School was Mechanical Drawing. It gave me the tool I needed to transmit (and on several occasions translate) ideas that needed a physical realization.

                      This has a direct connection to slot cars. I am using the basic concepts (although the tools are now a CAD program not my still preserved Dietzgen drafting set) to produce drawings to submit to a laser cutting service for a chassis design.



                      • #26
                        EM, I too started my career using pencil, paper and drafting machine. I did begin to migrate to computer drafting once it became affordable for average people. But I remember designing the Slide Guide and my model railroad on my home drafting table because my monitor's size and resolution made detail work difficult.

                        I actually quit one job because they were requiring their designers to migrate to AutoCAD. I had no problem with designing on a computer -- I designed my second house on a computer -- but AutoCAD gave me hives.

                        I had a job shop build and run the injection mold used to make Slide Guides based on my paper drawings. That was my first venture in custom slotcar parts. I did not get much change back from a US$10,000 bill. But I also got thousands of parts.

                        Back in the '90's I started having sheet metal slotcar parts made for me by a job shop. I designed those parts on my computer, but gave the shop paper drawings, which they translated into machine code. I could not generate the machine code myself. Those parts were made on a wire-EDM and a CNC drill.

                        Now I am making my own 3D printed parts in house. I design them in a CAD program and create the machine code in another. Still early days. But I have built cars using those parts, raced them, and not been too disappointed in the results. Seems like every week I generate a new batch of revised parts. At some point I'm hoping to have refined them enough to be truly competitive. I love being able to do it all in house and the quick development cycle.

                        If I ever get to the point of wanting to sell those parts in quantity I'll go back to that job shop and get them injection molded. That is still not something Joe Average can do, but it is the only economic solution when you want thousands of parts.

                        I'd love to have the ability to CNC cut sheet metal in house. I'm thinking affordable consumer-grade equipment might be another 5 years out.

                        I've already made photo-etched parts at home. And I've contracted to have some made by a job shop. They can produce better quality and quantity than I can. Not cheap, but I've been able to afford it. Sadly, those parts have not performed to my expectations. I'm not selling them.

                        I just love being able to design and build my own stuff. And I've had enough success to keep me going.

                        Some people run cars. Some people race them. Some people tune and modify them. I like to build them. I also like to race them, but the real joy comes from proving I've made something that can win.

                        Ed Bianchi


                        • #27
                          While testing the drive for a custom 1/32nd scale car the pinion gear drifted out of contact with the spur gear. I was surprised at just how long it took for the rear axle to spin down after it lost contact with the pinion gear and motor.

                          That rear axle used two miniature ball bearings -- both open and flanged. Cheap ones I had picked up on eBay. I had dosed them with some spray dry lubricant. Otherwise untouched.

                          I tried spinning that axle again by hand. Again it took much longer to spin down than I would have expected.

                          So I did it again while videoing. Only a quick flick of my finger, but it took 32 seconds to spin down! Check out the video below...


                          So, a number of things learned.

                          - Ball bearings really do have low friction

                          - Cheap open ball bearings can work just fine

                          - Spray-on dry lube may help. Almost certainly doesn't hurt.

                          I may have just gotten lucky with the ball bearings I bought on eBay. Just the same, I'm convinced that good ball bearings -- cheap or not -- are superior to bushings.

                          Well, yeah, I should do that spin-down test with a bushed axle. But I have a hard time believing they could match the performance of the ball bearing axle.

                          Ed Bianchi
                          Last edited by HO RacePro; 03-08-2020, 10:47 PM.


                          • #28
                            I'm convinced - will join the BB brigade.