Boca Bearings Workshop Weekly Update 12

It has been some time since we have updated you all, but we have been working on a number of projects lately. So, the first project that I will be discussing is the Power Wheels project car. Structurally, the Power Wheels car is ready for its first test drive. I finished welding the steering column more into place so that it was more linear with the chassis. I also welded the bracket for the steering wheel onto the shaft of the steering column.

So now the steering wheel is firmly mounted without question of it breaking off. The last task I completed on the Power Wheels car is adjusting the tie rods to the correct length. This was rather a challenging concept since John, Andrew, and I designed the steering geometry. You can also check the archives to see all of what we did to the steering geometry to validate that we had enough steering angle to actually turn the car. With that being said, I originally started out adjusting the tie rods to each be exactly the same length as one another.

This turned out to not be the case. As I tried to put each tie rod on, at the specified length, they would not fit onto the chassis at all. Not to mention that we were losing steering angle in one direction. So the “easy” but lengthy fix was to adjust each of the tie rods to different lengths that would not only fit but also give us the max steering angle that is geometrically possible. Yes, the problem is solved but it would have been better if we checked the Grashof conditions. In this scenario, a steering column assembly is purely a 4-bar Grashof linkage system. By checking the Grashof conditions as well as doing a couple lines of math we could of then determined the appropriate lengths for the tie rods as well as the coupler on the steering column.

This diagram demonstrates the one of the many Grashof conditions, but this will help you understand the idea of what I am refering to.

Besides the Power Wheels car I have been working on a couple of side projects/improvements. The most recently completed one was upgrading the our Monoprice 3d printer. I will say that the Monoprice printer has been printing exceptionally well lately, but we decided to push the envelop and try to make it better. In doing so we did a simple z-brace mod. The z-axis of the Monoprice/wanhao 3d printers is very weak despite being made out of metal. We printed 4 floor stands and two z stands that all bolt into the existing holes on the printer. Once assembled, we tried a test print and I will personally say that the mod did help but it for the most part it is hard to notice the improvement on simple parts. I am sure that it will be more obvious on a complex print.


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