Mechanical Engineering

I've been dealing with this for months. I've received yet another drawing from a company calling "Diameters on a common axis/center to be 0.XX" TIR U.O.I. "

Total Runout requires a Datum. Your "common axis" is not a datum and can not referenced. It's driving me mad. Like, where did everyone get this notion that it's acceptable? It'd be one thing if it was just one or two drawings, but I'm into the dozens at this point. It's getting to the point that I'm starting to question if I'm either the one in the wrong or everyone has some sort of mass psychosis.

Am I in the wrong here?

Scientists and engineers have successfully tested a high-powered laser weapon mounted on a British Army combat vehicle.

According to the Defence Science and Technology Laboratory (Dstl) and the Ministry of Defence (MOD), this trial marks the first instance of such a weapon being fired from a UK land vehicle.

Crosspost from the "Energy" Community. Seemed too good not to put here.

Just build a replacement nuclear power plant and reuse the water. Right?

I can't stand the SpaceMouse Pro. They ruined it! Why would they swap the nice tactile buttons for stupid gummy membrane buttons? And why coat the whole thing in nasty soft touch coating that is going to turn to goo? We peaked with the previous generation of space balls.

Since I've been working from home though, it has gotten quite annoying to unplug my SpaceExplorer and take it back and forth to the office. It would be so nice to have one of those fancy new wireless ones. But that's not happening, since they ruined it.

So, I added USB-C to mine, instead. Now, I'll just have a cable at the office, and a cable at home and just take the unit itself back and forth. I can even leave a USB-C to USB-C cord in my case, in case I need to use it with my laptop away from my docks! If anyone is interested, I can share the STL for the little breakout board mounting piece I made.

A University of Virginia professor believes he has discovered how to create a freeze-ray device, inspired by the Batman villain, Mr. Freeze. Rather than being a weapon, this device is intended to cool down electronics within spacecraft and high-altitude jets.

A tiny, hard-working bacterium -- which weighs one-trillionth of a gram -- may soon have a large influence on processing rare earth elements in an eco-friendly way.

"Traditional thermochemical methods for separating lanthanides are environmentally horrible," said Buz Barstow, assistant professor of biological and environmental engineering at Cornell, the corresponding author. "It's difficult to refine these elements. That's why we send rare earth elements offshore -- generally to China -- to process them."

Not sure how useful it is yet, but it sounds like with some AI and proper cameras you could use it to completely repair certain components. Theres something similar to this using electrochemical plating to repair microfractures throughout a component - only downside is that it takes like weeks to do it properly (I'll see if I can dig up the paper later)

Looking for some ideas for friends and coworkers. If anyone can think of anything cool, I'd love to see it.

The proposed fuel is not SAF, it's a combination of magnesium and hydrogen mixed with hydrocarbon fuel. It's estimated to give 8% more range over other existing aviation fuels.

Engineering memes was a favorite on a similar site that I used to use, wondering if this community would want some too

I just came across this video about a motorbike gearbox, and have a couple questions.

Firstly, she says the detent for neutral is between first and second gears. Why isn't it between fifth and first? That would seem to make more sense to me. Are you expected to shift down to first when setting off, then shift back over neutral to get to second? And presumably the grooves in the shifting drum have gaps between fifth and first to stop you shifting too high and ending up back in first, or is there another mechanism for that?

Secondly, and probably more importantly for my understanding of the transmission, can someone elaborate on how the 'constant mesh' transmission means it doesn't need synchronisers? For example, before the shift from neutral to first is shown, the input shaft, and the first free-wheeling gear with it, are rotating while the output shaft and the corresponding dog clutch are not. Surely, when the dog clutch is moved to connect with the free-wheeling gear, they wouldn't be able to mesh, unless it happened right when the recess and pin were in line, and even then that would cause a jolt. What am I missing here? I also watched another video with a physical gearbox, which seems to confirm that it works like in the first video, but doesn't explain it much, and I can't really see why it works.

I just posted this at [email protected] but realised it doesn't have much activity, so hopefully it fits here.