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  1. random_guy

    Perpendicularity to Two Datums

    Back in my day, the airbox would take at least 10 gallons.... :) In my experience, most machinists have a general working knowledge of the standard but I never expect them to know the standard cover to cover - and I have yet to meet a machinist that does. Chances of getting a call using...
  2. random_guy

    Perpendicularity to Two Datums

    My point was that a machinist or inspector that sees an angularity callout will likely be looking for a basic angle. I'd probably get a call to ensure that the part isn't 87° or something silly. And when I say, "oh, it just controls perpendicularity to those two faces", they'd more than likely...
  3. random_guy

    Perpendicularity to Two Datums

    I assumed that was the case - it's technically not perpendicular to both planes, but the intent is clear. And if I were to pass this drawing along to a machinist, I'd likely get a call asking why I have angularity on perpendicular faces, and where is my basic angle? Just another example of the...
  4. random_guy

    Perpendicularity to Two Datums

    Ah, total brain fart for me. I'll blame it on the Friday afternoon. Thanks Dave! Wise men learn more from fools, than fools do from the wise.
  5. random_guy

    Perpendicularity to Two Datums

    Y14.5-1994 shows perpendicularity to two datums, which I've always used (Fig 6-35, p.182). Y14.5-2009 and 2018 show perpendicularity to two datums but add an angularity constraint to A|B (Fig 6-4, p.101). I believe the intent is the same, but the addition of the angularity FCF is just confusing...
  6. random_guy

    Parallelism on a Slot

    I agree that it's not ideal, and it's not how I'd apply the GD&T, but it's not my drawing. Dave is correct in that an overall profile tolerance controls the location, and the parallelism is a refinement of orientation. Wise men learn more from fools, than fools do from the wise.
  7. random_guy

    Parallelism on a Slot

    That's what I thought. Thanks Dave! Wise men learn more from fools, than fools do from the wise.
  8. random_guy

    Parallelism on a Slot

    Can parallelism be applied to a slot? Y14.5-2018 shows it applied as a refinement to position of a hole (Fig 9-9 and 9-10). If I wanted to control orientation of the slot to a datum plane, but not necessarily position, I don't see why I couldn't. If it's applied in this sense, what does that...
  9. random_guy

    Angular Position of Grouped Holes

    3DDave - it's 6 holes, not 4. Essentially a mirrored pattern of 3 holes 90° apart. Eric - that's how Creo displays centerlines. Once printed they show properly. Wise men learn more from fools, than fools do from the wise.
  10. random_guy

    Angular Position of Grouped Holes

    Thanks, I meant to refer to that section but grabbed the wrong one when typing my post out. I think you're correct. If the centerlines were to extend to the center, then it would likely fit that definition. As is, however, I'm not sure it does. I find that too often we get hung up on these...
  11. random_guy

    Will straightness affect the circularity and cylindricity?

    Plenty of free CAD software out there. https://www.tinkercad.com/ https://www.autodesk.com/products/fusion-360/personal https://www.sketchup.com/plans-and-pricing/sketchup-free Wise men learn more from fools, than fools do from the wise.
  12. random_guy

    Angular Position of Grouped Holes

    There are 6 holes in the pattern in question (notice the vertical holes are a different size). The 6 holes are all controlled by the same FCF. I have applied a 4X 45° callout to the holes. A coworker believes there needs to be a 90° basic dim connecting the two groups. I think it's implied...
  13. random_guy

    Stress on strap wrapped around a drum

    The vendor states that the material is fully annealed. I asked if they considered stress-relieved to be annealed, and he said no, it's a full anneal. Who knows.... I got my answer regarding higher tensile and yield strength, and that satisfied me. :) Wise men learn more from fools, than fools...
  14. random_guy

    Stress on strap wrapped around a drum

    I spoke to the vendor. Those values are understated. Tensile as tested is 90-100ksi depending on the batch. Yield is around 40ksi. Coupled with conservative estimates in my fatigue calc, this solves my problem. Big thanks to everyone for your input! Wise men learn more from fools, than fools...
  15. random_guy

    Stress on strap wrapped around a drum

    If I'm getting 50% more tensile strength, that bumps my fatigue calc up from 5500 cycles to 75,000. More in line with our failure rate. I think the material properties are greatly understated. What a rabbit hole this has become.... Wise men learn more from fools, than fools do from the wise.
  16. random_guy

    Stress on strap wrapped around a drum

    Here is the material spec I have. It states annealed. Wise men learn more from fools, than fools do from the wise.
  17. random_guy

    Stress on strap wrapped around a drum

    Although, I am looking at the material spec again, and the properties are listed as minimum yield and tensile strength. I am now thinking that the actual values are much higher than that. Wise men learn more from fools, than fools do from the wise.
  18. random_guy

    Stress on strap wrapped around a drum

    btrueboold - you're absolutely correct. And my first suggestion was to utilize a stainless steel with a higher temper (I suggested 1/2 hard). I was not assuming the strap material, it is annealed 302/304, and those values are accurate. Wise men learn more from fools, than fools do from the wise.
  19. random_guy

    Stress on strap wrapped around a drum

    Thank you all for your input. This forum is amazing. MintJulep - it's not a constant spring, but good idea. However, the equation referenced there is the same equation I was using. dvd - These are excellent resources, thank you! Interestingly, their equations use Poisson's ratio. When I...
  20. random_guy

    Stress on strap wrapped around a drum

    That would be the axial stress. And it won't be reduced, the load supported will always be held by the strap. But there is a separate stress related to the bending of the material as it passes over the drum. That's where my discrepancy is. Wise men learn more from fools, than fools do from the...

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