#video on #surveillance-pricing and possible #price-fixing by #Instacart and retailers. Good despite the #clickbait title and faked screenshots
#Veritasium #video on snowflake growth and crystal growth in general
#Cylo #video on books about #machining #precision #mechanisms: Richard Moore’s Holes, Contours, and Surfaces, which is largely about operating jig borers; Douglas Blanding’s Exact Constraint: Machine Design Using Kinematic Principles; CRC Press Basics of Precision Engineering, edited by Leach and Smith; Balasubramaniam, Sarepaka, and Subbiah’s CRC Press Diamond Turn Machining: Theory and Practice; Rowe’s Hydrostatic, Aerostatic, and Hybrid Bearing Design; Kittell’s Precision Mechanics; Evans’s Precision Engineering: An Evolutionary View; Smith and Chetwynd’s Fundamentals of Ultraprecision Mechanism Design; Slocum’s Precision Machine Design; of course Wayne R. Moore’s Foundations of Mechanical Accuracy; and Dave Arneson’s blog post listing “50 tidbits”. Smith and Chetwynd is hard to find.
#Cylo #video on #precision #flexure #mechanisms, starting with “wobble pins” connected with “pairs of notch hinges”, and cascading two springs of different stiffness, so you apply a large displacement to the weaker spring, which produces a small force in the “colinearly attached” weaker spring, which then moves a four orders of magnitude smaller distance. From Smith and Chetwynd. He proposes the “diving board” flexure, where a force on the end of a cantilevered beam produces a small displacement on the opposite side of its fulcrum, the beam being pinned at its end to form the cantilever support with the fulcrum, the displacement ratio being (16/3)L₂(L₂ + L₁)/L₁², thus asymptotically proportional to the ratio of the squares of the lengths, enabling a large transmission ratio in a small package. His realization uses a cross-leaf flexure for the pin, a bearing ball in a screw for the fulcrum, another bearing ball in a screw to bear on the end, and a wobble bar to a four-bar parallel-movement flexure for the output, which he’s measuring with an LVDT. He even has antibacklash flexures on the threads of his screws.
#video on #bootstrapping “#Precision on a Budget” for a US$10 micron-resolution displacement sensor. Specifically he’s using the 8-blade linear-movement flexure Gelbart taught, but made it out of plastic with #3D-printing, with a knife edge in the beam path of an optointerruptor, which he superglued into it once he found the linear region of the optointerruptor. A steel BB on the other end of the linear-motion stage serves as his “stylus” for feeling a shaft or whatever he wants to measure the displacement of. Then he calibrates it with grade-0 (±150nm) gauge blocks from Mitutoyo. He estimates his error at ±5μm over a range of 700μm.
#video listing books on #machining, mostly high #precision stuff, including Precision Hole Location from the Moore Tool Company, as well as their other books; ASME’s Handbook of Industrial Metrology (#metrology); Frank D. Graham’s Audels Machinists and Tool Makers Handy Book [sic sic sic!] from 01941; Franklin D. Jones’s “Old-Fashioned Toolmaking”; Henry Ford Trade School’s Shop Theory from 01934; The Starrett Book for Student Machinists; Goodrich and Stanley’s 01923 Tool and Gage Work; Miller and Russel’s Toolmakers Handy Book; Calvin & Stanley’s Gear Cutting Practice, reprinted by Lindsay Publications; Henriksen’s Jig and Fixture Design Manual; Moore, Davis, & Coplan’s Building Scientific Apparatus; Shigley’s Mechanical Engineering Design (by Budynas and Nisbett); US Steel’s The Making, Shaping, and Treating of Steel; Frank Curtis’s High Frequency Induction Heating; the ASM’s Metallurgy for the Non-Metallurgist, edited by Reardon; Dossett and Boyer’s Practical Heat Treating; the ASM’s Heat Treater’s Guide; and Edward F. Connelly’s Machine Tool Reconditioning.
#video explaining that dipped ceramic disc caps with a black paint hat on the tip are NP0/C0G #precision caps. #electronics #hardware
#video by #AmyMakesStuff showing her #stealth-camping #Honda-Element car setup. Not very stealth, really. One really interesting thing is the bed: a wooden frame like for a futon, but instead of having a single giant futon on it, it has multiple separate cushions, which are held in place with velcro. Also she added snaps to the edges of her curtains to hold them in place over the car windows, with the other side of the snap “screwed directly into the plastic trim”. Smart. Her solar panel is suction-cupped to the inside of the moonroof, so it doesn’t protrude outside the car. Also her bed frame sort of slides together to be half the width to use as a couch I think.
#video #toread about a 19th-century linear dividing engine for #machining a ruler.