#video by #Harrison-Low on his jugglebot triumph. He finally switched from kevlar kite string to #UHMWPE for the linear actuators. Also he switched to #ODrive Pro electronics to control the motors. Featuring a #JLCPCB #3D-printing ad, sigh. Oh, also he burned out the hand motor because a sensor cable came unplugged. #robotics
on 02026-08-18#Harrison-Low #video about how his #Stewart-platform juggling robot finally can juggle, two balls anyway. He actually did switch from kevlar to #UHMWPE (Dyneema) which I thought wouldn’t handle the friction heat. He shows the pseudo-capstan “hand” #mechanisms that actually throw the juggling ball. Oh, and he's using Zulip instead of Discord to make it more open. #robotics
on 02024-09-15SheerlyGenius #UHMWPE pantyhose is now Sheertex.
on 02020-09-27Recommended #knots for #UHMWPE fishing line. A lot like a hangman’s knot.
on 02016-07-01Idiot fishermen don’t realize fishing line’s strength is proportional to the square of its diameter rather than to its diameter. This may explain some of the anomalies I saw in the strength ratings in the fishing store. One fisherman correctly complains about its lack of elasticity. (I’m investigating #UHMWPE line.) #materials
on 02016-07-01Pure Fishing’s Berkley brand’s Whiplash Orange fishing line is “100% PE #Dyneema” (i.e. #UHMWPE) fishing line. From their UK website, it costs £0.1166 per meter on a 300-meter reel in the diameter range 60μm to 200μm. They have some larger; 280μm, the thickest they offer, is rated at 44.9kg breaking strength, and they charge £42.99 for 220m, or £0.1954/m, or £279.99/2000m = £0.14/m. 44.9kg is 440 N, coming out to a stunning 7.15 GPa tensile strength, almost three times the rated strength of the 50kg 500μm “Whiplash Pro” of which I bought 100 meters for AR$100 the other day (AR$1/m ≈ £0.15/m). They no longer seem to carry “Whiplash Pro.” #materials
on 02016-07-01#PDF properties of #UHMWPE #materials, including volumetric abrasion (compared to many other chemicals), coefficients of friction, and density.
on 02016-06-02properties of a variety of #materials used in composites, including #UHMWPE.
on 02016-06-02#pdf #paper on #Dyneema #UHMWPE #materials properties (Young’s modulus, tensile strength at varying strain rates, etc.)
on 02016-06-02#Dyneema “Bully Braid” braided fishing line for AR$305 for 100 meters in either 0.14 mm or 0.18 mm diameter, advertised at 10.2 kg or 12.2 kg respectively. That would be about 6–6.5 GPa, which is over twice the yield strength Wikipedia and Polyco claim that #UHMWPE has.
on 02016-05-24The manufacturer of #Dyneema brand #UHMWPE lists tensile strengths from 2.2GPa (for SK25) up to 3.3–3.9 GPa (for SK78 and SK75), and tensile moduli in the range of 52 to 132 GPa, with a consistent 3–4% elongation at break. Density is .97 to .98 g/cc. #materials
on 02015-11-16300 meters of 0.3mm, 30kg Dyneema #UHMWPE braided fishing line costs AR$139 now (US$9). That works out to a bit over 4 GPa and about US$400 per liter. Most likely this is a fraud, since WP says UHMWPE’s tensile strength tops out at 2.4GPa.
on 02015-11-16