/r/engineering
r/engineering is a forum for engineering professionals to share information, knowledge, experience related to the principles & practices of the numerous engineering disciplines.
r/engineering is NOT for students to ask for guidance on selecting their major, or for homework / project help. Read the sidebar BEFORE posting.
If you see any post or comment that violates these rules, please report it so the moderators can respond in a timely manner. Thank you.
No questions related to university, school, major selection, GPA, coursework, etc. NOTE: Asking for help on homework will result in an instant ban. DO NOT DO IT.
No questions on "how something works" — try r/AskEngineers.
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r/engineering is a forum for engineering professionals to share information, knowledge, experience related to the principles & practices of all types of engineering: civil, structural, mechanical, electrical, aerospace, chemical, computer, environmental, etc.
Questions about current engineering projects you are working on, how to interpret codes and standards, and industry practices are all encouraged. Engineers should help each other to make the world a safer and better place.
Images and videos related to engineering are acceptable, provided they are relevant to engineering. Completed projects, destructive test results, and unique machinery and hardware are all acceptable and encouraged. Lead-in comments are required to provide context to the readers.
Pick an engineer from the list of volunteers below and send him or her a PM indicating that you would like to conduct an interview:
Directory of Useful Subreddits
/r/engineering
Posted this in r/chemistry, but it deserves some respect here too.
Some 40-50 years ago, I was attempting to implement the NASA RP-1271 (or possibly an earlier variant) chemical combustion equilibrium code, developed by Gordon and McBride, on a clunky old MS-Dos clone. I decided to send an email to the developers, and Ms. McBride replied, and then called me (at the time I was a young rocket engineer). Helpful, polite, knowledgeable and witty - she helped me figure out how to get the code to run reasonably well, and chatted with me about ways to tweak the numbers for what I was trying to do. Yes, I was surprised, a bit, to be chatting with a female person, but not as much as you might think (my wife is also a rocket engineer and I grew up around smart women).
Replying to a post in Chem Engr., I brought up this topic again. And then decided to see what became of her. This is what:
https://www.nasa.gov/centers-and-facilities/glenn/glenn-history/bonnie-mcbride/
I knew she was a looker. Smart chicks always get me fired up.
Have an electric winch on my boat. Uses small 1/8 rope and 2 ft of 1/8 chain. About 8 inches, or 1 wrap of chain will wrap around rope, on drum in housing, when stowed. I want to add 5 ft of 3/8 chain to the end. Note... A davit is 1 roller to allow anchor line to drop in water off top of bow. Allowing 90° drop, and also holds anchor when stored, keeps it from swinging in the wind.
Can I install 2 statationary pulleys to more or less, store 3/8 chain, make up the difference in length of new 3/8 chain, keep the 3/8 from winding on my rope drum ?
Instead of running in a straight line, from winch to davit, I'll have,
1 pulley in front of winch, where davit is now. 1 pulley next to winch. Move davit to in front of 2nd pulley, to the tip of the bow.
I'll have an " N shaped path. Winch and davit for anchor, would be mounted at each point on the "N". The 2 points of diagonal line on the "N" would be stationary pulleys. Which would "store" larger 3/8 chain. Allow 1/8 chain and rope to pass thru rollers.
Would that affect lifting capacity ? If...proper chain roller pulleys are used. I'm not introducing mechanical advantage, or snatch blocks, only using pulleys to allow a bigger chain at the end, between current 1/8 chain and anchor. Increase distance between Davit and winch drum. I DO have a basic drawing, but didn't know how to post a picture in this post. Will this work ? Thanks !
Any tips or guidelines for designing a facility with a self destruct sequence? I've scoured the local and national codes and can't find anything. Has to be ADA compliant too. I've reached out to local demo contractors to determine where the charges should be placed already to provide space in the walls to make sure the architect is pleased with the way they look.
Specifically looking for timer length recommendations.
Any tips on how to go about learning PV Design.
I been digging thru a bit but havent structured in compress.
How much can we expect to lesrn in the firdt year. Im 6 months in and want to show some progress.
I'm a tradesperson turned mechanical technologist. I work in design for a late stage startup. Our shop floor and tool situation is... Chaotic. I joined up the the terminal phase of a failed 5s environment, where it’s too late to save it without chucking it all and starting over. Plundered drill indexes, wrenches disappear, etc.
I'm from a shop floor background, I've been a part of and know what a successful 5S environment for production looks like. I know what works when it’s all trades and production cells, but an R&D environment is different. More fast paced, more variety, it’s much much harder to begin the 1st stage of a 5S, the “sort”. We need a wide variety of hand, power, fabrication and measuring tools available in a fairly unpredictable pattern.
Our main issue is tools disappearing. My usual approach to that is to “flood” and “identify”. People steal tools when they can’t find what they need, and don’t return them when they both forget to return, and forget where the tool came from.
I want to have enough tools to have them readily available, and have the tools so obviously identifiable that you can see from 10 feet away if that tool needs to go back to its home.
I don’t like tools in drawers. I want to see everything fast. If I can’t find my tool, as someone new, in less than 15-30 seconds, it’s a failed system. The problem here is 5S boards aren’t usually very dense, without putting incredible amounts of work into a careful layout that inevitably becomes out of date when your tool requirements change. Maybe a “see through” drawer? Does that exist?
So how do I solve the 2 main issues:
1- Storage in a visual shadowboarded way for large amounts of unique tooling,
-Multiple vertical leaf through panels? Like they used for flipping through posters
-I actually like screws or bolts in thick plywood, but that has lots of other issues. Main advantage is easy to reconfigure.
-Shadowboard tracing I have had luck with simple paint marker outlines. The main problem with shadowboarding is it is so labour intensive to setup.
2- Tool identification. -words are not obvious enough
-tape doesn’t last
-spray paint is ugly (but an option)
-I’ve seen nail polish enamel used with success
I’m just hoping for some examples and advice here… A pretty shadow board example where they have pliers, cutters, a wrench set, and a couple sockets isn’t going to cut it.
Hi folks, I have a vessel working at mawp. I am a little worried about overpressure. By law, does this require a PSV?
The code is a little confusing for me.
Hi everyone, I am designing a system where I need to measure flow in order to regulate it close to but not exceeding 0.5gpm. I already have the flow regulator I will use the McMaster-Carr precision flow adjustment valve 1/4 inch with a 0.51 max flow coefficient (https://www.mcmaster.com/46425K12/).
In order to measure precisely the flow so I stay close to 0.5gpm I am considering using the Swissflow low pressure flowmeter, (https://www.daitron.com/sf-800) since it is the only reasonably affordable flow meter I could find that is able to measure flows under 3gpm.
I am trying to keep the design as simple and affordable as possible. This will be an external standalone design.
What display could I use with the Swissflow flowmeter in order to get a reading? Would the display be enough to get it to function?
Am I over-engineering this? Is there a simpler solution for staying close-to but not exceeding 0.5gpm?
TLDR: What display could I use with a sf-800 Swiss flow flowmeter?
any feedback is appreciated 🙏
# Intro
Welcome to the weekly career discussion thread, where you can talk about all career & professional topics. Topics may include:
* Professional career guidance & questions; e.g. job hunting advice, job offers comparisons, how to network
* Educational guidance & questions; e.g. what engineering discipline to major in, which university is good,
* Feedback on your résumé, CV, cover letter, etc.
* The job market, compensation, relocation, and other topics on the economics of engineering.
> [Archive of past threads](https://www.reddit.com/r/engineering/search?q=flair%3A%22weekly+discussion%22&restrict_sr=on&sort=new&t=all)
---
## Guidelines
* Job compensation
* Cost of Living adjustments
* Advice for how to decide on an engineering major
* How to choose which university to attend
## Resources
* [The AskEngineers wiki](https://new.reddit.com/r/askengineers/wiki/faq)
* [The AskEngineers Quarterly Salary Survey](https://www.reddit.com/r/AskEngineers/search/?q=flair%3A%22salary+survey%22&include_over_18=on&restrict_sr=on&t=all&sort=new)
* **For students:** [*"What's your average day like as an engineer?"*](https://www.reddit.com/r/AskEngineers/wiki/faq#wiki_what.27s_your_average_day_like_as_an_engineer.3F) We recommend that you spend an hour or so reading about what engineers actually do at work. This will help you make a more informed decision on which major to choose, or at least give you enough info to ask follow-up questions here.
* For those of you interested in a career in software development / Computer Science, go to r/cscareerquestions.
Hi everyone,
I’m currently working on a project involving PLS-Tower for the analysis of transmission line structures. A significant part of my work includes creating and managing Angle Group files, but manually inputting this data is quite time-consuming.
I’m looking for ways to automate the creation of these files using tools like Python or any other scripting language. Here are the key points I’d like advice on: 1. Is it possible to automate the generation of .pls or .lca files for Angle Groups? 2. Are there specific formats or requirements I need to follow for PLS-Tower to accept these files? 3. Has anyone here worked on similar automation tasks with PLS-Tower and could share examples or useful resources?
I’d appreciate any suggestions, documentation, or guidance that could help me move forward on this topic. Thanks in advance for your help!
Best regards,
I work for a tech start-up. We have teams whose work is composed of administrative, labor-intensive, manual work. Our engineering team is working on ML and automation models to alleviate the need for humans to do this work. Some of the engineers are anxious that the work they are doing will eliminate the need for their co-workers jobs on the other teams. Have any of you felt this way in your jobs, i.e. that your work might mean fewer employees are needed and you are torn/anxious about that? If yes, what has helped you work through this?
I am designing something that will probably use a roller chain with extended pins on one side only to actuate something, but I have never worked with extended pin roller chains before (also not had much to do with roller chains either).
As the force is on one side of chain and therefore induces a moment on the chain along the rigid axis, it seems that there should be some special design considerations that need to be made, but I'm not found anything.
Google has not been much use (not that's it's good these days) and I've tried looking at the manufacturers guides and catalogues hoping for some starting place, but not everyone carries them and those that do don't seem to include any special data specific to them. I can't even find things like basic maximum load data for double sided extended pins!
I'm hoping someone might be able to point me the right way.
Solidworks or Inventor?
Lots of 304 eye screws, but google search is annoyingly inconsistent and does not filter despite using the minus shortcut. Any recommendations for manufactures would be greatly appreciated.
Hi
i'm to use some threaded rod like a lead screw - just normal M20 thread not trapezoidal - and want to have the lowest coefficient of friction between surfaces - probably choosing between zinc plated (not hot dip galv) and black oxide. it will be greased, moderate humidity climate and no weather exposure. but i cant find decent data.
can anyone advise or suggest between the two?
thanks!
Hello everyone,
I am asking if anyone out there has any idea where I can purchase more venturi pumps. We use them in our steel mill on a regular basis and the normal supplier we use (Fischer Scientific) has discontinued the product.
The product in question is: https://www.fishersci.com/shop/products/airejector-aspirator-pump/11474208?
I have found other "venturi pumps" but a lot of them are getting stupidly complicated for the application, and many of them are less robust than a fully metal piece (lots of them are plastic from what I see). The environment it would be in is greasy, hot, and full of abrasive dusts. I worry about the longevity of polyethylene parts compared to nickel plated brass.
I hopefully need a new supplier (so not just someone who has a couple left that they want to get rid of so they can discontinue the listing), but I will take any leads I can find right now.
I have searched Mcmaster-Carr, Schmalz, sciencekitstore (found 3 here, but that's all they have and will ever have), and Humboldt (I think they have parts that we could work with).
I want to ask if anyone out there has any idea where I can find these things in the U.S. I would have thought it shouldn't be hard considering every chem lab I was in through school had these on the sinks so that you can draw a vacuum for filtration, but apparently these things are becoming hard to find from what I am finding.
Picture of what I am talking about (this is from humboldt, I can't find a picture of the one from fischer scientific): https://prolabscientific.com/images/product/P-5565.jpg
Also, they are sometimes called air ejectors on these websites, not only venturi pumps
Thank you for any help you are able to provide!
Hi all. I am trying to design a fixture that essentially rocks a flat plane back and forth. I was going to do a lever type deal but the torque is like >50kFtLbs. I moved the fulcrum to the center and reduced torque a lot but now I want to use smaller pistons instead of a single double acting. I tried researching online to find info about common design practices for having this setup but I can't find anything. Basically, I'd need to set it up such that one is pushing while the other is pulling and vise versa. I know you can hook up opposing ports but I don't know much about parts selection and such. Anyway, I am just looking for any texts yall may have that I could reference to design the system. Thanks.
Processing img ak52mtoxjs1e1...
This camera enables flexible study of animals in areas with poor cellular reception, such as the mountain ranges of Colorado, or rural farmland.
“Chronic wasting disease (CWD) is a serious disease in animals such as deer, elk, moose, and reindeer. Since first reported in the United States, CWD has spread to animals in more than half of the states in the continental United States. It is always fatal in infected animals. There is no vaccine or treatment. CWD is a type of prion disease.” - CDC
Processing img yady5p8lyq1e1...
Processing img r811taxgyq1e1...
Studying and mitigating Chronic Wasting Disease (CWD) can prove challenging in animal populations. It’s difficult to incentivize hunters to volunteer their efforts as they go about chasing a prized game animal. Hunters have to volunteer tremendous effort, time, and cost to assist. In addition, due to the nature of remote environments, it’s difficult to collect and send data. Any given state’s local Department of Natural Resources (DNR) has limited resources and it can be difficult to plan where to expend those resources on managing CWD.
Colorado for example has continuously struggled with CWD within their deer, elk, and moose populations. Recently they found an increase in certain populations like the White River herd in White River National Park. The terrain can prove challenging to navigate and cell signal is not guaranteed usually due to the deep valleys from large surrounding mountains that block signal.
A trail camera that performs extremely well under constrained cell signal conditions can help collect data to further study and make more informed and timely decisions when planning and managing CWD within animal populations. For the case of Colorado, this trail camera can collect data about animals within valleys via satellite and be moved to ridge lines of surrounding mountains where cell signal is present to send the images.
Local DNR can set up and move multiple cameras themselves or try to incentivize local hikers to move cameras to be more efficient and save cost. Cameras could be continuously rotated between ridgelines and valleys for when data needs to be collected. Thanks to the use of satellite data transmission, it can be easily figured out when these cameras should be rotated to a different location for either uploading the data or collecting more data.
Processing img hcvnplr9yq1e1...
How does it work? Let's Walk Through an Example!
Let's use Pascal, our corgi friend, as an example. He's standing in for a deer, wearing antlers and laying in front of the trail camera. The camera detects movement by comparing images with difference hashes or using a PIR sensor. Once Pascal is in front of the camera, these methods help detect his presence and determine when to save an image.
Processing img 5x1mo327yq1e1...
The metadata from the original image is sent via satellite using the Starnote notecard to Notehub and then routed to a Django web app.
Processing img 3paestk5yq1e1...
The data sent includes:
{
"img_dhash": "0e2e0e0e0e6ec607",
"h_dist": 8,
"loc": "6FG22222+22"
}
Images that look perceptually similar also have similar hashes. The measure of similarity or dissimilarity between these hashes is called the Hamming distance
, labeled as h_dist in the metadata. This value is calculated by comparing a periodically taken image's difference hash to a more frequently taken image's difference hash. The greater the difference between the images, the higher the Hamming distance
value. This helps determine how much of the camera's field of view is obscured by whatever triggered the recording, providing insight into how interesting the image might be for further inspection.
Knowing the Hamming distance
allows us to decide whether to remotely download the image or take other actions regarding the trail camera. It also reduces false positives by preventing unnecessary alerts from the camera being overly sensitive to movement.
When enough images accumulate on the trail camera, we can either move it ourselves or ask someone to relocate it to an area with cell reception. We can also gauge the number of stored images and get a sense of their quality.
On the web app, we can request to download Pascal's image if the Hamming distance
is above 3, which, in a static environment, often indicates something worth inspecting.
Once a request is sent, the web application sends a command back to the Starnote via satellite for a specific image:
{
"img_dhash": "0e2e0e0e0e6ec607",
"method": "cell"
}
When the hardware receives the request, the image is resized from its original 480x640
(500KB+) .PNG
format to a 120x160
(10KB) .JPEG
. The resolution is reduced by a factor of four in both width and height, and the change in file format results in a 50x reduction in file size. This smaller .JPEG
is then sent over cellular data.
You can see the .JPEG
stretched back to its original resolution for comparison, revealing a loss of quality and visible compression artifacts.
The hardware converts the .JPEG
to a base64
encoded image and breaks it into chunks for reliable transmission. The chunks and the status of sent images are tracked in IMAGES_SENT.json
. Once the web application receives all the chunks for an image, it reassembles and displays it. An example json message is shown below:
{
"b64_chunk_total": 54,
"b64_img_chunk": "qLuc86dpWOO1a9l1TUprybhpWyF/ujsPwFdl8O9J8uKXVZl+Z8xQ59P4j+J4/A1y",
"chunk_index": 39,
"img_dhash": "0e2e0e0e0e6ec607"
}
Pascal is now made whole again. However, he's still fairly low resolution and hard to see. What's great is that the web application makes use of a model called xenova/swin2SR-realworld-sr-x4-64-bsrgan-psnr
to bring the resolution up on the client side via a library called transformers.js
. You trigger this functionality through the Enhance
button. A model to upscale images to save on data transmission costs and create a better user experience is by far the most underrated science fiction to become a possibility in recent years.
Why yes, we apparently can nowadays.
It does a sufficient job of making the small image clearer. Despite some loss of detail, it's still possible to discern whether an animal's ribs are visible or if its spine alters its silhouette, which could indicate CWD, a different disease, or malnourishment. This model increases the resolution by 4x
, allowing us to send lower-resolution images, save data, and reduce transmission costs.
Pascal now has an airbrushed appearance, but it's clear he is a well-fed good boy. While some detail is lost, the edges and shadows are preserved well enough to check for visible ribs or spine. This is notable, given how little of the image he occupies. The same process could be used to count deer, elk, and moose suspected of having CWD, helping the DNR track the spread of the disease and allocate resources more effectively.
The software and hardware are open source: https://github.com/legut2/Sat-Cam-New-Way-to-Study-Animals
Hey all, I am looking to get some feedback/inspiration on a design of mine for a truck rollbar I want to fabricate. Main tube will be R8 while this is not structural and can be made of something cheaper. I'm making a function that allows a controlled part to pivot 90* with a linear actuator. Total weight of bar and associated hardware will be around 13~16kg or 30~35lbs. Any way, I am in need of advice on how to have it pivot.
Here is what I got so far:
Now the tube dimensions at the moment are:
If using a roller bearing, I was thinking of pressing it into the tube and using a similar method as above. Alternatively, a larger bearing pushed into a modified blue part and insert the tube into the ID of the bearing.
So, pivot on the brass bushing, use a roller bearing in one of the ways above; or something else completely?
Open to advice and all that.
Thanks.
Hi all
I'm looking for a knockoff swagelok (factory is on back order for 1/8th brass elbows). Any good alternatives that I could check out?
Cheers
# Intro
Welcome to the weekly career discussion thread, where you can talk about all career & professional topics. Topics may include:
* Professional career guidance & questions; e.g. job hunting advice, job offers comparisons, how to network
* Educational guidance & questions; e.g. what engineering discipline to major in, which university is good,
* Feedback on your résumé, CV, cover letter, etc.
* The job market, compensation, relocation, and other topics on the economics of engineering.
> [Archive of past threads](https://www.reddit.com/r/engineering/search?q=flair%3A%22weekly+discussion%22&restrict_sr=on&sort=new&t=all)
---
## Guidelines
* Job compensation
* Cost of Living adjustments
* Advice for how to decide on an engineering major
* How to choose which university to attend
## Resources
* [The AskEngineers wiki](https://new.reddit.com/r/askengineers/wiki/faq)
* [The AskEngineers Quarterly Salary Survey](https://www.reddit.com/r/AskEngineers/search/?q=flair%3A%22salary+survey%22&include_over_18=on&restrict_sr=on&t=all&sort=new)
* **For students:** [*"What's your average day like as an engineer?"*](https://www.reddit.com/r/AskEngineers/wiki/faq#wiki_what.27s_your_average_day_like_as_an_engineer.3F) We recommend that you spend an hour or so reading about what engineers actually do at work. This will help you make a more informed decision on which major to choose, or at least give you enough info to ask follow-up questions here.
* For those of you interested in a career in software development / Computer Science, go to r/cscareerquestions.
Hello, I'm designing a large machine that has a very nice operator cabin: AC, mini fridge, microwave, the works. I need to put a little chair in it that attaches to the wall and folds up so a trainee can sit with the cab operator and learn how to work the machine, but I can't find any I like. I did a lot of googling around and found model # 6844 offered by northern tool + equipment.
I really want something that looks a little more robust than that one, and ideally would weld the to the wall of the cabin so when the seat folds up it has a very minimal footprint. It should have at least a little bit of cushioning, I don't want just bare metal, otherwise I'd just have the shop weld something together for me. Thank you in advance. (Also budget is around 650$, and it should really just be an off the shelf item, nothing custom ordered)
I have a very specialized project for which I need a relatively flexible string-like wire (diameter somewhere in the neighborhood of .010-.050) with highly consistent diameter over a 8" length. I've found 1080 music wire with a consistency of somewhere in the ballpark of +/-.0001, but it is a bit too stiff and prone to kinking for my application.
Does anybody have any suggestions for other options to try? I realize the two aspects I need (flexibility and minimal diametral variation) are nearly strictly opposed, so I want to try a few more options to find a happy medium.
To be clear, it's not a specific diameter I need to a very tight tolerance, I need a very tight circularity tolerance along the 8" of wire I am using.
Edit: I forgot to mention, the maximum tension on the string is 10lb.
# Intro
Welcome to the weekly career discussion thread, where you can talk about all career & professional topics. Topics may include:
* Professional career guidance & questions; e.g. job hunting advice, job offers comparisons, how to network
* Educational guidance & questions; e.g. what engineering discipline to major in, which university is good,
* Feedback on your résumé, CV, cover letter, etc.
* The job market, compensation, relocation, and other topics on the economics of engineering.
> [Archive of past threads](https://www.reddit.com/r/engineering/search?q=flair%3A%22weekly+discussion%22&restrict_sr=on&sort=new&t=all)
---
## Guidelines
* Job compensation
* Cost of Living adjustments
* Advice for how to decide on an engineering major
* How to choose which university to attend
## Resources
* [The AskEngineers wiki](https://new.reddit.com/r/askengineers/wiki/faq)
* [The AskEngineers Quarterly Salary Survey](https://www.reddit.com/r/AskEngineers/search/?q=flair%3A%22salary+survey%22&include_over_18=on&restrict_sr=on&t=all&sort=new)
* **For students:** [*"What's your average day like as an engineer?"*](https://www.reddit.com/r/AskEngineers/wiki/faq#wiki_what.27s_your_average_day_like_as_an_engineer.3F) We recommend that you spend an hour or so reading about what engineers actually do at work. This will help you make a more informed decision on which major to choose, or at least give you enough info to ask follow-up questions here.
* For those of you interested in a career in software development / Computer Science, go to r/cscareerquestions.
It's been 6-7 years since I took thermo and I think I borrowed the book. I do mostly mechatronics, but might be doing some projects where thermo is something I need to brush up on. Any good recommendations for something terse?
Hello!
Looking to get the UL 1741 SB Certification (inverter safety certification) on a product. I've heard how important it is to have a consultant to help you with that process. I was wondering if anyone here had any consultant recommendations?