Call for Engineers: Tell us about your job! (2020)

I require a 50A neoprene gasket but my vendor can only source 60A. From what I can find, there are no hard and fast rules to gasket hardness specifications although I admit, this is entirely new for me so I don't know what considerations I need to make. How should I approach approving/rejecting this recommendation?

I am a graphic designer creating a product catalog for a machine and fab shop and I have found myself a bit confused by roller chain sprockets. I haven't been given their engineering information for these products because the former engineer that worked here was not very organized and so no one has it all in one place. I've been learning everything I can about chains and sprockets using other similar catalogs and ANSI/BS standards. I am struggling to understand some things about the sprockets aspect despite several days of searching. This information is important for me to be able to make a comprehensive "engineering section" and to make sure that I don't miss anything that is important for a customer to know. I will list my questions and if anyone knows any of the answers I would really, really appreciate it. I apologize if these are very basic questions and I just did a poor job trying to find the answers but I am a graphic designer, not an engineer or mathematician.

1. Why do tooth counts in product listings skip? For example in the Tsubaki and Martin sprocket catalogs 35 sprocket teeth jump from 36 to 40 and I do not understand why that is. I worry that if someone was following the formulas to determine a roller chain selection the math might point them to a 37 tooth sprocket and when they go to check the dimensions of it there will be none to tell them what, say, the maximum bore is and then they won't know if it can fit on the shaft. Is there a reason why some tooth numbers just don't exist?
2. If most roller chains go up to 6 strands why have I only been able to find information on up to triple sprockets? Or in the case of 25 roller chain only single sprockets despite the chain having up to 3 strands. Are two triple sprockets put together on a shaft when 6 strand chain is used or do sextuple sprockets exist and I've just not been able to find them?
3. Is there a way to calculate the maximum bores and hub diameters for a sprocket? I have been able to work out formulas for pitch diameter, outer diameter, and bottom diameters but I have not been able to find a formula for bores and hubs.

If anyone needs the catalogs that I am referencing I can post links or dm the pdfs but most can be found when you search for them. I'm very lost so thank you in advance to anyone who can help me

I'm looking for the name of the following item https://imgur.com/a/V1k5Z2k

It's a rubber cover / seal where a shaft can go through. I'm looking for one but I don't know what its called.

I recruit engineers (automotive, software, aerospace, manufacturing and industrial) but I was truly amazed at this platform I saw last night. Absolutely amazing!! Even the platforms for last years Super Bowl. Now I wanna know more. Who designs these? Do you have to get insurance to have these types of structures? How safe and how much testing is done?

How can we check if the cl2 stored in cylinders (tonners) is contaminated. I'm facing issue with a vacuum chlorination system where the materials (especially PP) in the flow path is eroding in excess. (liquid cl2 entry is ruled out)

For example when using a rotary phone, the wheel spins back to its starting position when your finger is released, what is that called? Thanks in advance!

Is there a mechanism where the screwing motion (along the horizontal axis) moves an object in the vertical direction (No gears).

So lets say there is a housing flooded with an oil. In the housing is an electrical component, producing a consistent amount of waste heat. The oil is pumped through the housing to cool down said component. Now I want to compare two oils in the regard of which one is cooling better. The inlet temperature is steady at 20 °C and the flow rate is pretty small, so its in a laminar regime. The outlet temperature of the first oil rises more or less linear over the tested time to about 31 °C. The second oil reaches about 29 in the same time. Now what I don't quite get is this: higher temperature difference between inlet and outlet means more heat is removed (the thermal properties of the oils differ, but not that much, actually the heat capacity of the first oil is larger). But at the same time, if the temperature still rises over time, it must mean there is a temperature difference between the component and the oil. So I assume the component has a higher temperature with the first oil, although more heat is carried away? Maybe I am not seeing an obvious thing but I hope you can help me out. Thank you very much.

Hi AskEngineers, I thought you might have some good insights into this.

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Creo Simulate with availability for static, linear simulation just became available in the office. Do you think this would be at all usable in the designing of the products made from ABS/PP/PA? I was thinking that we could at least use it for identification of critical locations and predicting yield. I realize that beyond the point of yield this would be totally useless and that the stress results from the displacement driven simulations would be off.

Hello, where would I find data comparing 2mm steel pop rivets and solid head rivets tensile strengths? I'm researching failure methods at university and this is part of the information I need, and I can't seem to find it.

Any help would be appreciated :)

Then why does India not have a fleet of advanced indigenous fighter jets? Why does she need to rely on Soviet/American jets?

What are the necessary conditions required to build such advanced fighter jets? Like political will, huge R&D budget, and what else?

The garage was added to my house sometime in the 80’s, it’s a 4 car garage with a concrete foundation and an attic truss bearing on the exterior walls. There is a loft space created by the trusses, it’s previously and currently used for storage.

I’d like to turn the loft into a work space - adding lightweight flooring, drywall, desks, and some storage.

I found a manufacturer tag on the truss and called them, that company is out of business.

How can I find out how much weight the loft can support and if my plan is safe? Is this something a structural engineer can easily evaluate?

We're putting together a new process that uses toluene, chloroform, methanol and a few other reagents during processing, and then the equipment (metal and glass) gets cleaned between batches. What analytical tests could be used to validate that the residual chemicals were rinsed off of the equipment? Thanks!

I’m trying to build a soft gripper but I’m stuck on the pneumatic part of it.

What I understand:

How air from a compressed air source is passed into the soft gripper

What I don’t understand:

How air is released from the gripper to deflate it

[Questions]:

Is it a circuit of 2 actuators?

What type of actuators are used?

Does the circuit use a vacuum pump??

All in all, I’m confused as to how a solenoid valve allows air into the soft gripper and vacuums it(from the soft gripper) at the same time.

https://imgur.com/a/bXjFV01

Trying to find sensor replacement but can't find that anywhere aside from buying a whole new micron gauge. (this sensor head is perfectly fine was used to make sure the other one was borked)

I can't seem to remember where I found it but I remember seeing that the PSI needed to make super critical co2 is under the PSI that can be generated by a nitinol heat engine. I don't know if I'm using the right units here. I'm wondering about using the co2 from a composting reactor as the feed source for the co2.

(Pardon my English, I don't know the technical terms even in my own language [italian]) I'm doing a DIY project which I came up with to build a pottery wheel all on my own, by designing and 3D printing the components that I need. Unfortunately I thought too late about the torque that the motor has to handle (by the force applied by the potter) and I'm worrying that it could cause some problems. I bought a 24v 600 rpm DC motor, that I intend to connect to the wheel via two double-helical gears with a ratio of 2.4:1, so that at max speed (and no load) the wheel should spin at 250 rpm. The chart of the motor says that at load it can handle 0.5 Kg•cm of torque, but the speed is decreased to 420 rpm, it also says that it will stall at 1.65 Kg•cm of torque. Now, if I'm not wrong, the gear that I designed should increase the torque it can handle by a factor of 2.4, so the motor could handle 1.2 Kg•cm and still go at a top speed of 175 rpm. THE QUESTION IS: Is it enough torque for entry level pottery?

Bought that stupid levitating spinner that floats above a magnet ring, discovered that some, but not all, my forks stick to its magnetic base (i.e. enough that when stuck by its head, the handle can hold its own weight).

The magnetic one says "18/8 stainless steel" on its handle; the non-magnetic "18/10".

Was the magnetic one not annealed properly? Both are cheapest most generic "LingBingBing-Co-Ltd"-from-Wish-esque.

Supposedly authentic Herdmar is also magnetic, despite their site claiming 18/10.

EDIT-UPDATE:

After some investigation, magnetism seems to be most present in spoons/forks/... with pressed patterns. Apparently, it requires a VERY high pressure press that induces stresses so significant that they cause "stress induced martensitic transformation".

Feel free to confirm or deboonk, thanks in advance.

Edit: it’s for middle school 6-8th grade.

Just got a new role at a new school transitioning from general science to Design and Engineering. While I am very confident in my ability to teach it and make it fun - I am looking for some good places to start and help generate some ideas or even maybe entire units.

So far I know that I want all projects to follow a similar flow of something like:

Design -> feedback -> iterate -> prototype -> feedback -> iterate -> finished model -> Peer-review

In addition I know I will start out small to introduce the engineering / design process with something like building a boat out of aluminum foil or spaghetti bridge.

Also thinking about simple machines as an early project. Maybe a catapult or something.

I also know I want to partner with the computer science teacher toward probably Q3 to collaborate on a project of some sort (robot, security device, or w/e).

The school has 3D printers and laser wood cutting machines and potentially would purchase anything I need.

My back groin is NOT in engineering and tbh - while im also SO excited for this opportunity, I’m a bit nervous.

Any suggestions, links to resources, ideas or really anything at all, would be so helpful as I start to plan out the scope and sequence.

Thanks in advanced for any help!

Edit 2: why the down votes… like? I donno. Seems unnecessary.

Sometimes on old farm plots we see old wooden windmills which were used to pump water from the ground using the wind. They were replaced with electric ones for the sake of efficiency and reliability because the wind can blow from many angles and its force can vary resulting in inconsistent water pumping or too much water pumped. I wondered if adapting the wooden windmill with a rotative head and a fantail to always face the wind and with shifting gears to slow down the pumping when the wind blows too strong was feasible. Also would there be a way to store energy from excess wind without electricity? I don't have a windmill or plan to have one; it's just for my realm of ideas.

I have a vertically oriented shaft supported by bearings in two locations. It has a fan mounted on one end and directly coupled to a motor at the other end. I’m trying to determine the reaction forces at the bearings when the fan is running at a constant speed in order to evaluate the support structure. I have forces for the fan thrust and mass of the fan/shaft in the direction of the shaft axis. I’m unsure of what radial forces I should consider. If I assume the fan/shaft are perfectly balanced then would there be any radial force on the bearings? Am I missing something?

For some context, this is not a homework problem, this is a partially completed project I just inherited from a coworker who has left the company. I am trying to make sense of the forces he used and I can’t figure out how where the radial forces have come from.

Thanks!

Hi! I have read that canards are bad for stealth due to corner to hull. But aren't regular elevators/horizontal stabilizers the same? The only real difference is that canards are at the front, correct? Thank you!

https://imgur.com/a/JukJk7W (first photo - attached to fixed position, second photo - loose support to have a good look into the bearing)

Me and my friend are a member of a lab in our university. This is part of a pick-and-place robot that was made 15+ years ago. The robot failed and dropped from 1 meter into the ground while not in operation. It seems that the coupling between the servo and the ball screw was very loose because the ball bearing was slipping downwards into the support and after decoupling, the robot was free to fall. After falling, the ball bearing in the ball screw support is free to move inside the support. Does anyone know how to fix it? Do we need to remove the entire ball screw mechanism? Is there a way to fix the loose bearing or does it need to be replaced?

I need to make a silicone prototype of essentially a kitchen cooking mat that has suction cups on the bottom. For prototyping, I'm less concerned about the overall product and really want to 3D print or even pour at home a silicone prototype to test the suction cups functionality and overall design/look.

I currently have my STEP file and am working with someone who can do MJF 3D printing of molds. They wanted to first use TPU because it would be more flexible than SLA, but now they are saying their is a size limit to TPU and instead are suggesting Nylon.

Do any of you who are more familiar with these materials and methods have a suggestion on which would be the best for a flexible, working prototype? Again I'm totally fine narrowing the test model down to just the suction cup aspect since the rest is basically a flat kitchen mat with a slight lip around it.

Alternatively, instead of trying to get a physical prototype delivered, would it make more sense to try to get a robust mold delivered and then I could pour some sort of silicone into it, let it cure, and extract it from the mold myself?

Finally, if my end goal is to produce this mat from a factory in China anyways, would I save a bunch of time and money simply mailing them the two suction cups I'm modeling mine after and telling them to make sure the final mold must have that same size, functionality, and aesthetic? In my limited experience working with China for textiles, I feel like I want to hand them 100% exactly what I want and not rely on them to try to engineer anything, but maybe if they have a working silicone suction cup in hand, and are ultimately making the steel compression molding anyways, this would be a better option?

https://imgur.com/a/KrU1ZVq

Hubless spur gear Hex bore - 14mm ID - 20mm OD 10, 7mm teeth. 8mm thick

I don't have a 3d printer otherwise I'd just print it :(

No part number

I’m sure there is a mechanism for this or some term that I just don’t know. Haha

I am going to 3D print something where I have a large 3d circle that rotates with an outer ring that needs to rotate separately. Probably will be roughly 2 feet in diameter total.

I have a few ideas on how to maybe do this, the inner circle could just be rotated from the center, and I was thinking for the outside ring to rotate it via an inner gear or something. My main concern is how to best keep that outer ring attached? I could have a lip that the outer circle sits on and somehow rolls around, or find something like a very large bearing that can keep it together?

I’m open to suggestions on any aspect. Especially if there are any terms or things I can look into that might help.

Edit: Not a great explanation above, and circles weren't the best way to describe them. I basically want to make this clock: https://www.youtube.com/watch?v=ayUM4QALK9g&t=269s Where the outer ring moves for each minute, and the inner circle moves for each hour. I've got the basis of the electronics, so controlling some motors to rotate gears to get the right rotations and positions and all that. So the main question I currently have is how to best get that outer ring to rotate while also keeping it from falling off.

Hello fellow engineers! I've got a personal project that has me stumped and I am hoping that someone might have an idea, concept or knows of a similar mechanism that could help me out with this design. Image link below with sketches.

Fundamentally what I am trying to achieve is to have a handle that is attached to a horizontal structure that can slide. This will allow the holder ( two flat pieces of wood at a 90 degree angle) to slide out roughly 22" keeping the load horizontal.

Once the holder has been pulled the 22" out, while still pulling horizontally the holder would rotate 90 degrees in place to stand the load upright. Then the load could be removed from the holder.

The process should then be able to be reversed when the load is deposited on the holder and pushed back into the space.

Put simply, I have a tall item (`20 lbs.) that I need to store inside of an enclosed space. It of course cannot fit vertically (21.2" opening and 22" tall item), because of course. I realize that I could simply create a drawer fundamentally that slides out and that would work. The 90 degree rotation at the end would just be very helpful and a big "quality of life" improvement to have.

I sketched the concept I kind of had, but I'm having issues with realizing it and am not sure that it will work.

I've been googling around and looking up possible mechanisms but I am not finding something that could work. If anyone has any ideas, concepts or mechanism types that they think might work I would greatly appreciate it. If not, thank you for taking the time to read this and I hope you have an awesome day.

https://postimg.cc/CZrnV2Zb

I’m adding some support in my house and need to pour footers. The crawlspace goes below the grade outside the house maybe 2 ft. Our frost line in Ohio is like 3 ft. Should I dig an additional 3 feet in the crawlspace to be safe, now being about 5 ft down?

Hello AskEngineers,

I am looking for suggestions for some sort of DC load I can hookup to a stack of cells + BMS assembly to demo some features of the BMS. I'd like to be able to transport this around, which is why I can't just use an electronic load. In lab settings I'll use this variable resistor box (https://www.bellnw.com/products/clarostat-240-c) but it is pricey and large for demonstration purposes.

Ideally I'd be able to tell some FAEs to buy them as well, and the resistor boxes are well outside what an FAE can spend to bring to a demo, and most of what I've seen on the internet is stack posts of people trying to build something like this themselves which may be an indication that what I'm looking for doesn't exist.

When looking I found this (https://www.sparkfun.com/products/14449) but it is out of stock everywhere, but it is almost exactly what I am looking for. Being able to turn a nob/press some buttons to increase current draw quickly and easily to show OC/SC protection and show off some SOC features as well. Ideally being able to support 10s, or even 16+ cells would be great.

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Hey,

Somehow I'm 3 years into my engineering course and only just thinking this

Moments are force times distance, but if that distance was say, 0.1m, the moment's would decrease from the point load, ie, if the point load is 100N and the distance it acts is 0.5m then the force at that point is half what is on the point load

This doesn't feel right to me, why only is it when I get a distance away of over a metre does the moment start to increase? Surely any amount of distance is a mechanical advantage, not just where we arbitrarily set 1 meter to be

Thanks anyway, I'm sure this is a stupid question

edit : i’m not arguing that the meter is special, i’m asking why this makes sense intuitively