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  1. geesamand

    Documented practices for tack-welding hardware

    It’s reassuring that I’m not the only one who thinks it’s a very poor solution for a host of reasons, and I’m sure we could each write our own thesis on good reasons to abolish the practice. Sadly, none of us are likely to change my customers opinions. So I’m still on the hunt for published...
  2. geesamand

    Simple Roller Bearing

    I'll posit that there aren't any good 'book' values for calculating the friction of rollers immersed in seawater. If that's actually how your design will function, you'll have to test or make conservative assumptions to get started. If the bearings will have conventional lubricants (oil or...
  3. geesamand

    LEEB Rebound Hardness Testing

    Our Leeb has worked relatively well for incoming inspection, where we are screening for bad material and we don't required highly accurate results. That said, it works poorly on light parts and unmachined surfaces. Castings also have innate hardness variation. It is inappropriate for hardness...
  4. geesamand

    Is it mandatory to use Helical gears(drive-driven) as a set? Is mix usage OK?

    If the gears are ground quality, free of surface wear, and made of a sufficiently hard finish like carburizing or nitriding, then they should be fully interchangeable. The big risk is if they are bevels that are lapped as a pair, or when one component is through hardened and a 'break-in' has...
  5. geesamand

    Efficient way to generate work instructions with slight variations?

    There is software for making instruction manuals where the content is written in 'chunks' and merged together as you view and use the document. It's called structured authoring. Of course that allows you to keep the alike content perfectly alike at all times. Sorry I don't have more specific...
  6. geesamand

    Agitator design

    Agitator design (for economy and performance) is a multi-faceted matter. The size and proportions of the vessel are critical, as are the properties of the fluid. The best impeller choices may be axial flow, radial flow, high shear … it all depends on the vessel geometry, required shear at the...
  7. geesamand

    Gear & Electric Motor Specs Needed

    Tricky question because an ice skater can apply sudden bursts of thrust as they skate or stop, and those could translate into shock loads on the drivetrain. These are notoriously tricky to estimate on paper and generally come down to durability in practice.
  8. geesamand

    Torque limit of a socket head hex drive

    Exactly the kind of information I was asking about, thank you. David
  9. geesamand

    Geometric tolerancing of bearing holes to avoid bearing misalignment

    Personally I wouldn't trust anyone who uses runout for keeping a machined feature square to an axis. That's perpendicularity all day long. Once you have a functional tolerance scheme, the real question is what angular misalignment will the bearing withstand before a degradation in performance...
  10. geesamand

    Torque limit of a socket head hex drive

    btrueblood, Good point about the ball ends. On a design level, I can specify that but I need to ensure there is room to torque each fastener using a straight driver. DAVIDSTECKER, Turn_of_the_screw: The point is that I do not trust a standard torque calculation by itself. If I must, I will...
  11. geesamand

    Torque limit of a socket head hex drive

    Hello everyone, Today I'm designing an assembly that must be 100% 316 S/S and I have good reason to use button head socket hex head screws. It's been my experience on small assemblies that these hex driven heads can strip out. So I assume my usual torque specifications for 316 S/S are too...
  12. geesamand

    Allowable bearing forces due to unbalance

    My company designs gear reducers with attachments. The balance quality of the attachments follows our company standards but it's a very basic practice. These are rigid rotors operating safely below first critical speed. Balance quality can be calculated from the allowable bearing forces. How...
  13. geesamand

    Thrust Stand Design

    I had good success putting the thrust bearing alone at one end to handle radial and all thrust load. On the other end of the stand I used a single taper roller bearing. We set the end play as if it were a pair of separated taper roller bearing. Elegant and effective.
  14. geesamand

    Radial Load to Torque on Bearing

    I once explored this question because hand-rotating a shaft with a torque wrench is a way to establish preload on a set of opposed bearings. Think pinion bearings on the rear axle of a vehicle. I was unable to find any equations that worked with the low rotating speeds. I suspect it's because...
  15. geesamand

    Export to Revit

    Interesting. We may have an Inventor license still in our company, so I could try exporting from Creo to Inventor using STEP or Parasolid, then look into how to get it from Inventor to Revit. It's crappy of Autodesk to do this, because our customers are saying "hey I want to buy a pump, I...
  16. geesamand

    Data on Cost Bias for Geometrically Dimensioned and Toleranced Parts?

    I wouldn't say those things out loud when your ISO 9001 auditors are around.
  17. geesamand

    Data on Cost Bias for Geometrically Dimensioned and Toleranced Parts?

    Since you didn't quote or reference anything, I'm going to assume it was referencing my post prior. To whit, how is GD&T not affecting cost, when the inspection operations required to confirm the part in GD&T terms cost more than the part itself? The point I've been driving at is, GD&T is a...
  18. geesamand

    Data on Cost Bias for Geometrically Dimensioned and Toleranced Parts?

    Well if it didn't have positional tolerances, I'd use a tape measure and/or a dial caliper. Unless you have a tape measure that consistently evaluates true position tolerances...which I do not.
  19. geesamand

    Data on Cost Bias for Geometrically Dimensioned and Toleranced Parts?

    I was thinking more about this, and how obviously GD&T boosts price when working with small quantities of low-accuracy parts. Take for example a bracket sawcut from a short length of angle iron. Drill two holes in one side of it. While GD&T says I should place a true position on the holes, so...
  20. geesamand

    Offerring gear material

    It appears to be a PMI gun. My limited understanding is they don't report small carbon contents accurately. The other alloys are what lead to a steel grade identification. Also I see some typos above with mfgenggear (who knows a ton and must have had a bit of brain fart): I think we mean 0.1...

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