161–170 of 196 posts
Earlier quoted context omitted.
HDPE is also what Nalgenes and the like are made of (or used to be anyway), and is very popular for storing chemicals as well. It is very nearly completely inert.
you cunninghammed me: nalgenes are polycarbonate, which is a lot less inert all the polyethylenes are relatively inert, because polyethylenes are in some sense just heavy paraffins. paraffin is germanized latin for 'relatively inert'
Earlier quoted context omitted.
I'd really like to see some backing of these claims. I've seen "grain flow" claiming big gains for years in various enthusiast magazines (bike, motorcycles, cars, etc) as to why components are forged. Then I started working in engineering, and I can't find any support for these claims. For sure when a steel bar is worked down to become wire for a steel rope, it cannot be pulled to an elongation of 100x increasing str…
MIL-HDBK-5 [1] is a good publically-available source for strength allowables for several aerospace alloys, including multiple directions relative to the grain for some of them. The first relevant example I found was on page 3-86, extruded 2024, 2.250 - 2.499 inch cross-section. For ultimate tensile strength, F_tu, the L (in the direction of extrusion) allowable is 57 ksi, while the LT (perpendicular to the direction…
> Forgings have the added advantage of variable grain direction which generally can be tailored to the stress patterns of a specific design. This is a super underappreciated fact! It's often repeated that forging is just stronger, but just squishing steel does NOT make it stronger. Forging a part is so much more than just smashing it into a shape. Steel cable is made of pretty ordinary steel which is stretched 100s o…
> By the early 2000s, parts from the heavy presses were in every U.S. military aircraft in service, and every airplane built by Airbus and Boeing. >The savings on a heavy bomber was estimated to be even greater, around 5-10% of its total cost; savings on the B-52 alone were estimated to be greater than the entire cost of the Heavy Press Program. These are wild stats. Great article! I was fascinated to learn about the…
Columbium is apparently an old name for niobium, and one perhaps still in use by American metallurgists.
There's no way anyone was making huge niobium forgings, though. Or nickel? Surely this is a reference to the use of those elements in superalloys.
Earlier quoted context omitted.
HDPE is also what Nalgenes and the like are made of (or used to be anyway), and is very popular for storing chemicals as well. It is very nearly completely inert.
you cunninghammed me: nalgenes are polycarbonate, which is a lot less inert all the polyethylenes are relatively inert, because polyethylenes are in some sense just heavy paraffins. paraffin is germanized latin for 'relatively inert'
Some Nalgene's are polycarbonate, like those commonly drunk from. But not all, some are HDPE[0,1,2].
Some are Polypropylene co-polymer[3] but those are more for specialist things I guess.
[0] https://ultralightoutdoorgear.co.uk/ultralite-1-litre-wide-m... [1] https://www.cotswoldoutdoor.com/p/nalgene-hdpe-125ml-wide-mo... [2] https://www.elitemountainsupplies.co.uk/camping-trekking-c4/... [3] https://www.thelabwarehouse.com/products/bottle-nalgene-ppco...
Love them or hate them. Tesla's manufacturing prowess is unmatched.
These massive presses are/were of strategic importance. Something politicians, most of whom seem to be lawyers these days, completely fail to grasp. I am not in general a fan of government subsidy, but I was very disappointed when the government of the UK declined to fund a large press in Sheffield, which would have been used to build the next generation of nuclear reactors. June 2010 timeframe. Luckily natural gas i…
We're not going to build the nuclear reactors either. The problem will finally be solved by re-permitting onshore wind and a lot of batteries imported from China. (The "local supply chain is vulnerable to political uncertainty over long term project funding" problem is much worse in regard to trains, and has resulted in losing most of our train building capacity. See HS2 fiasco.)
At heart, this is the story of using less labor to product a unit of output, and possibly also improving the quality of those units of output. This led to much better outcomes for society. Was anybody then scared of what would happen to the riveters? Maybe, but those voices would have been drowned out.
These days, production is demonized, particularly at scale. Is there any successful producer being celebrated for being so? Are there any new, innovative, labor-reducing technologies being celebrated?
Does it take a war to snap us out of our fear of being better?