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Recent content by gb2835

  1. gb2835

    Are these equivalent?

    Burunduk, 100% agree. And the thought was just that, if TP orientation can apply to a pattern then it can easily apply to a single feature, thus being equivalent to Perpendicularity. And I bought into that with equal convincing. FYI, I was also told to use Concentricity to control coaxiality. I...
  2. gb2835

    Are these equivalent?

    3DDave, let me probe this a bit further to clarify something that I may have been mislead on in the past. I've seen a lot of TP being used to just define orientation, not location. For example, a TP on a hole referenced to datum [A] which is a flat surface. Nothing special here, just a single...
  3. gb2835

    Are these equivalent?

    Thanks 3DDave and sendithard, I think you both have collectively reminded me of something. To be fair, I put the .000 tol as a default. The actual drawing had something like .010 tol. But yes without the FCFs in the figure I provided the envelope / median line principle accomplishes the same...
  4. gb2835

    Are these equivalent?

    See attached. I understand that with the left FCF that Rule 1 no longer applies. The right FCF, though a different symbol, controls the same thing (form of axis). Would Rule 1 also not apply with the TP? This came up on a drawing I reviewed. I told the designer to switch the TP to Straightness...
  5. gb2835

    Hall Sensor Spacing for BLDC Motor

    Cool diagram! I have a question if that's alright. How do the number of poles play into the diagram? Again, I am very new to this :)
  6. gb2835

    Hall Sensor Spacing for BLDC Motor

    Our lab previously purchased several BLDC motors with 21 pole pairs and 36 stators. These motors did not come with hall sensors, and previous lab members produced a pcb containing such sensors. They based the spacing on the hall sensors on the number of stators, so the sensors are 40° apart (80°...
  7. gb2835

    1045 CS - Corrosion Prevention

    Great, thank you both! This lead to some informative searches on my end regarding inhibitors and shear stability. We're going to order a few variants and see what works best across components. My advisor sends his gratitude.
  8. gb2835

    1045 CS - Corrosion Prevention

    I work in a lab where several gears, shafts, etc. are 1045 CS. I was tasked by my advisor to look into methods that help prevent corrosion. These components are used in walking robots in normal room settings, so no moisture minus lubrication on the gear teeth and oils from skin contact...
  9. gb2835

    minimum wall thickness of the four holes to the O.D. of the part.

    So pick a start and end point, one on a hole surface and the other on the OD of the part that sets the min gap calculation. You can think of the start point being fixed, and then you work through the stack up in a way that pushes the end point toward the start point. Pro tip, rotate the part 45°...
  10. gb2835

    Is this Corrent?

    I agree with everyone above. TYP is not a standard notation, so it is ambiguous. I've worked with enough people that do this, and when they explain it the same way as the vendor. Since they explained the symmetry thing, just go with that. But refer to @drawoh in the first sentence for the...
  11. gb2835

    Drawing Resources For Plastic Manufacturing

    So in the end it really depends on the mold maker for how detailed (if any) 2D drawings should be. In the past my drawings have only shown design specific features for the mold (rib thickness, various fillets at the inner corners, draft, threads if they are present, etc.) and locations of any...
  12. gb2835

    Gear Grease Recommendation

    Thank you TugboarEng, all great points. I will look into your recommended lubricants. I would certainly prefer 400 SS, but I am at the mercy of my advisor on this one. After testing, the gear assembly will be used with higher load thus the usage of steel, but yes a smoother material would help...
  13. gb2835

    Where do engineering companies pull there interview questions from?

    I am in ME, but have held interviews along with a panel and we all had our questions for the interviewer. I have not heard of anyone using a reference specific to interview questions, though I am sure you can find example questions online. As far as I know, we all have written our own questions...
  14. gb2835

    Swing Bolt Torque Calculation for Pressure Vessels with 0-ring Closures

    +1 to the above. I missed the o-ring mention in the title.
  15. gb2835

    Gear Grease Recommendation

    My advisor has tasked me with finding a grease to use for our gear assembly. The gears are not in a gearbox, thus oil is not ideal. The gears also work at low speeds (on the magnitude of a person's walking gait cycle). Temperatures are also on the magnitude of room temperature (not constantly...
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