r/AskEngineers

So, a decade or so ago, I bought a set of Wera drivers. Really nice stuff. I got the kraftform, because playing with electricity is scary, and insulation is sexy. Anyway. I noticed that the Phillips bits fit really well. Like, precisely. On a whim, I tried it on a screw that had been stripped by a driver from a big box store. It worked. So, whenever I saw someone at work about to drill a stripped screw, I'd stop them and ask to have a chance. I couldn't get *all* of them. But like 4 times out of 5. Enough to confidently say that the Wera is a superior driver, considering it or be a 100% fail rate otherwise. And after the first month or so, coworkers were asking for my fancy driver before going to the drill.

So, question is *why* are conventional drivers crap? When asked, I've been guessing that cheap drivers are saving a fraction of a cent per unit, but the savings add up at scale. I've also noticed that a Stanley #2 is small enough to turn a #1 (not well, don't do it). Is that possibly intentional? The Wera #2 cannot fit a #1 at all. Or is there maybe another reason the tools from big box stores are just... Different?

i'm working on a project that involves a custom mobile structure and i'm about to lose my mind

i've been trying to get basic information from the manufacturer for like two weeks now. just simple stuff like section properties for the floor panels and the grade of aluminum they're using. nothing crazy

every time i call i get transferred to someone else. i leave voicemails. nobody calls back. i send emails and get one sentence responses that don't answer my question

i finally got someone on the phone today and asked about the connection details between the fixed and expanding sections. he said it's standar and i asked what standard and he said you know, standard

i don't know what that means

i guess you get what you pay for

anyway i'm not really asking anything specific. just venting. but if anyone has tips on getting fabricators to actually provide technical information i'm all ears

I'm not really mechanically inclined and am currently taking chemistry, but this topic and cars in general have fascinated me recently and while I can understand how a normal crankshaft and balance works somewhat, how is the Porsche's supposed to work?

A normal crank is just one long rod of usually forged metal so how does that weird ring with gears in the middle supposed to connect itself to other 'Cranks' with multiple cylinders across multiple cylinder banks?

I am a junior in engineering. I connected with a recent grad of my school working in the area I'm interested in, and he gave me the contact of a senior engineer at a huge engineering company who also works in that area. After emailing, he agreed to call / chat next week, and I'm quite excited and nervous.

What do you think I should try to gain from this call? I obviously know better than to directly ask for a referral / job, and I have a couple questions I want to ask, but do you have any overarching advice or guidance for how to make the most of this opportunity and future networking opportunities?

A character misunderstanding the meaning of "high-octane fuel" and filling their car up with pure octane from the chemical factory sounds like a gag from a cartoon. I found myself wondering what would happen if you did that in real life. Would it work fine or would the lack of other compounds/additives cause other problems with the engine?

I have been learning about RC delay circuits recently. I understand the math and everything, it makes sense.

The real question I have is why/how.

For example, what about the electric field or potential or whatever term it is that determines the capacitor must charge first before the "rest" of the wire sees the source voltage? Why is the current simply not halved at the junction as it is with basically anything else?

Visual of Hitch / Carrier setup I am considering for CX-5

I’m looking for some real-world experience/advice on carrying an electric motorcycle on a 2021 Mazda CX-5 Touring AWD.

Setup:

• 2021 Mazda CX-5 Touring AWD (2.5-liter Skyactiv-G four-cylinder)
• Draw-Tite Class III / 2" receiver (76138)
• Velocity Volts Charge Carrier, ~22 lb
• Talaria Komodo emoto, 158 lbs (battery removed)
• Total weight carrier + bike: ~180 lb
• Anti-rattle hitch clamp
• Bike is secured to the carrier through the foot pegs clamps & straps

The CX-5’s max tongue weight is listed at 200 lb, so I’m technically under the rating. However, the Charge Carrier puts the bike’s center of mass roughly 17" behind the hitch pin, so I’m concerned that the leverage/moment is substantially different from a conventional trailer tongue load.

I’m planning on driving conservatively and avoiding rough roads, but I’d like to know whether anyone here has experience carrying an emoto/e-bike of similar weight on a CX-5, or has engineering knowledge about whether this is a reasonable/safe setup.

Interested in real-world experience, relevant Mazda guidance, or advice on what I should measure/check before relying on this setup.

Not looking for a textbook answer here, more curious what people actually do in practice. Say a part's been running fine at one shop and then gets moved to a different one (same drawings, new vendor). How deep does the requalification usually go for you in that situation?

Full GD&T reverification on the first article is one option. Spot-checking whatever dimensions have burned you before is another, and honestly probably more common than anyone admits. I'm also curious how much people actually trust a new supplier's material certs versus pulling a sample and testing it themselves, and whether any of that changes between a machined part and a molded one.

Mostly trying to get a feel for where people draw the line between reasonable diligence and redoing the whole qualification from scratch every time a part changes hands.

Does anyone know what they're called? I think it starts with a "p", and I'm not sure if it's "piezo" or something else. I have heard that they're not very effective - I just like the idea

I'm an engineer but not a structural guy. Hopefully I can ask this with the right inputs and terminology. I think most of my question is more material properties at this point.

I am building a gym in my garage. I'm not concerned about protecting the concrete slab at this point, but rather the underlayment that will create a moisture barrier / room for water to evaporate out. The barrier I am looking at is rated at 10,000-12,000 psf (69.4-83.3 psi). This will between the concrete and the rest of the flooring stack.

I currently plan to have about 2 to 2.5in of plywood topped with 0.5in of rubber in the primary drop zones. That thickness is mostly dictated by a platform that will basically be a giant wedge to counter garage slope in one area, then maintained throughout. So the total flooring stack up will likely look like:

0.5in rubber
0.75in plywood
0.5in plywood
0.5in plywood
0.5in plywood
Underlayment
Concrete

For reference, standard deadlift platform practice is 2x 0.75in plywood topped with rubber.

So to the question at the heart of my problem - how much is the impact load distributed by all that plywood and rubber?

If anyone actually knows a good assumption or numbers for the wood/rubber cushioning, lets also assume a 495lb barbell dropped from 3ft.

I have bumper plates, but for sake of simplicity for now lets just assume they're iron with no bounce. They're 2.3in wide, there would be 10 total with 5 on either side of the bar. I don't know what is reasonable for how much of their diameter squarely hits the floor in reality. Hopefully someone who knows about dropping circular stuff is on here?

for a while now people have been having sooo much trouble with them and getting them to work right.

but they just don't seem to work well at all? how come? is this on purpose? why do they not make a model with all the fixes and sell it?

we get problems like the machine just suddenly stops working after a clean with white vinegar

(i had to open mine which was hard and i ended up breaking it anyway to reach up in there to push a button with a paper clip and pliers to reset the machine!)

coffee sometimes tastes burnt even after a clean machine. (machine makes water too hot?)

some machines just give up anyway after a short while.

i am sure that there is a much bigger list of problems with the keurig machine than this list i made.

it makes me wonder why they even make them still. even the expensive models are acting like cheap ones.

love the concept hate the execution.

Good afternoon. Let us say that two pieces of metal are bolted together. Two parts to the question:

1. I would imagine the only part of the bolt that is under tension would be between the head of the bolt and the nut. Is this correct? Thus, the part of the threads beyond the nut are just…present, not actually doing anything and have no forces on them.
2. How is the length decided? As long as the bolt can sufficiently pass through all materials and have at least one thread (arbitrary?) beyond the end of the nut, wouldn’t that have the same outcome as 30+ extra threads?

Thank you for your input!

I need wiring and connection details.
dimensions.
How much time i use once connected to Flight controler board
and how i choose for defence application

As a reminder, /r/AskEngineers normal restrictions for career related posts are severely relaxed for this thread, so feel free to ask about intra-office politics, salaries, or just about anything else related to your job!

I have a pilot operated regulator on a machine. TACO Model R53-201-00B0. It balances the Z-axis using an air cylinder. OE Techs think it might be bad/dirty, as it appears to be loading down the z-servo, during motion. Control has a z-force feedback. I set the balance force to 0, but it climbs/drops too fast/quick as the z-axis moves, causing too high a load, so the servo alarms.

I cannot find any info on it. I believe it has been discontinued.

How can I test the regulator, to verify it is working right?

I found some remnants of broken air line inside. I know they replaced the OE air pressure regulator. So I suspect the pilot or control orifice is clogged or restricted.

If you look at a tv remote with your phone camera youll see the infrared light coming out, but your phone cant function as a night vision camera because of a certain ir filter in its camera/lens. So can I see infrared from my phone or not? And if my camera filters the ir light how can I see the infrared light from the tv remote?

I need an off-the-shelf industrial fan that produces a strong vortex effect. Ideally the fan is no more than 16" to 20" in diameter but I can go 24" in diameter if that is the best option. Ideally the fan will have a stepless speed control and will produce a high CFM. This is for a science project which will be shared at the Orlando Maker Faire. The fan will "float" a 36" diameter balloon or beach ball. The vortex produced by the fan will allow people to move the balloon up and down (with the speed controller) and side-to-side / front-to-back (with a custom controller). Please point me to a fan design that might be able to meet my needs.