I need to source this hinge and am coming up blank on what to call it. The tubing is approx. 3/4" OD and the tubing end of the hinge goes inside the tube. I am not certain on how it couples together.

https://preview.redd.it/jub0502zdlde1.jpg?width=1512&format=pjpg&auto=webp&s=6e14a3463dec592f919eaba5672e060a4ca63641

I want to create a relatively large (~20'' diameter, ~10'' tall) cylinder that is transparent (for use in a laser system) and watertight (to serve as a tank). The base does not need to be transparent.

These are uncommon dimensions and difficult to find a vendor that sells anything close to these dimensions. Some vendors like UVacrylic (https://uvacrylic.com/plexiglass/acrylic-tube) do offer open-ended tubes that I can cut to the desired height and attach to a custom base, but these are 1m long and expensive, so there will be a lot of waste.

I'm wondering if anyone has advice or suggestions on how I can custom fabricate it? I have access to a machine shop, including a CNC machine. I'm also open to using glass, and outsourcing certain tasks. I have a budget of $300 but would prefer to get this done as cheaply as possible.

One idea is to take acrylic sheets and bake it in the oven. Then bend it to the shape of a cylinder and use waterproof epoxy to seal it. Then finally, epoxy it to a base. However, I am concerned about the watertight-ness as well as the structural integrity due to the water pressure. Any help is appreciated, thanks!

I’m specifically work for a distributor but our lines include robotics, motion & control, safety, RFID/Sensors/vision, pneumatics, linear actuators, aluminum extrusion, etc. pretty much covering anything on the factory floor.

Anyone here in a similar industry or involved with it?

Greetings,

I'm trying to reverse-engineer a machine for home use (please see attached video).

I have a good grasp on the internal construction, except that the extension must be 2/3 of the total cycle (retraction being 1/3).

I have a feeling this can be solved with a four-bar linkage, but I haven't spent enough time with them to know for sure. Perhaps there's another linkage I haven't considered?

Any thoughts are appreciated, thanks in advance.

Hi guys

In EU, so no imperial please.

When you design structures that use e.g. a metal frame to which a wooden panel gets screwed. How do you manage the details like holes (countersunk, regular, slot, ...) and wood screws? Are there standards you use for manufacturing in Europe and China? With bolts it's easy and built-in (currently using SW) but with wood screws I'm a bit lost.

Thanks for any help!

I have run across one of these before in my search for CFM airflow testing. I found one very much like it in France, but with a different number of rings. There is one currently on eBay which is identical aside from the gauge. Does anyone have any information on this or a set of instructions?

https://preview.redd.it/bsfyw398z0de1.jpg?width=3024&format=pjpg&auto=webp&s=b639ede1b2189ba2680a37ebfc827163c31816ba

Airablo link

eBay link

I’ll provide below a short description of the problem with given circumstances and you come up with a solution you believe to be most cost effective and practical.

A 40’ shipping container needs to be moved approximately 20’ transversely to its length. DL is 10kips (contents included) and currently sits atop 3 railroad ties.

Conditions: The container is in a pasture full of grass with surface conditions slick enough to get a 3/4 ton pickup truck stuck (2WD).

Railrod ties are $20 ea.

It would cost $450 to have a piece of equipment come out and move it from the dealer.

It would cost $700 to rent a t770 bobcat

A gas 4cyl 1963 Ford 2000 tractor is available https://www.tractordata.com/farm-tractors/000/2/5/255-ford-2000.html

And a neighbor with a similar tractor is also available.

If the tractors aren’t able to pull it due to slick surface conditions as well, how would you move the container with cheapest option?

You can ask whatever questions you want and they will be added to the post to help others.

Hello everyone,

I wanted to ask if anyone could recommend any good sources or materials for studying engineering mathematics. I’m looking for something that explains the concepts clearly and provides useful practice problems.

# Intro

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I never use reddit, however a clients request has me stumped. They are planning a project to build a home using middle-eastern / roman building practices and techniques in USA climate zone 3-4. The plans for this are relatively sound albeit a bit strange for the region they have picked (namely a large courtyard) but have made significant efforts to accommodate for this. Their budget is essentially unlimited. One particular request that they have been an immovable object on is the composition or formula for the concrete used to lay the foundation, first story walls and facade. They are insistent that it is not just similar, but the exact same composition found in ancient roman architecture like the pantheon and whatnot (volcanic ash, quicklime, aggregate, pumice, etc.)

I'm worried that it won't be as structurally sound as other concrete mixes, especially given a freeze-thaw cycle in northern climates. As ideas to perhaps modify or add a material to increase structural integrity?

Fuck, marry, kill is a type of question like "would you rather", except you have to choose what would do "fuck" (maybe do some side projects with, or some really cool shit), what would you "marry" (use for the rest of your life etc), and what would you "kill" (never use ever again)

Hey all,

I'm looking for resources (books, YT channels, twitter accounts) that teach the magic of engineering. I don't have a specify area of interest atm.

Thank you!

Totally serious here. I would say the requirements are 100-meter accuracy with 10-meter accuracy preferred. It needs to act like a water balloon, which means that it "explodes" on impact, releasing the water. Ideally it would be good to send it 10 kms, but let's say if it's not at least 1km it's probably not worth doing. Bigger is better, the equivalent of a helicopter water drop is the target I would pick.

What are the challenges? Needs to be a material that will contain the water and not break in flight, while opening on impact without causing secondary damage. Needs to be a shape with a predictable aerodynamic profile, to minimize aiming error. Has to be able to be filled in minutes, and transported in bulk (along with the launcher) to a fill spot.

I doubt this is a wholly original idea, and based on my search I don't see a great solution. What I don't know is how far people have pushed-- has it been tried & failed, does the physics just not work? Could you even employ something like SpinLaunch and have a range in the hundreds of miles?

I have a question. I have a cylinder with semispherical heads. Size is 140mm diameter, 350mm overall length, 210mm between the head seams. The vessel is a strap-restrained elastomeric bladder. Circumferential straps are of high strength webbing (UHMWPE/Dyneema), webbing width is 30mm wide x 1mm thick, spaced in contact side to side.

Properties of Dyneema:

Tensile Strength, Ultimate, 3500 MPa, 508000 psi ; (I de-rate that by 25% to 2,625 because the strands in webbing aren't parallel to the load).

Modulus of Elasticity, 110 GPa, 16000 ksi ;

Tenacity, 3.53 N/tex, 40.0 g/denier.

Breaking strength 1640 DaN

Working pressure 500 kPa (Design safe working 5x 2500 kPa)

Hoop stress at working pressure, I should get Stress Sigma 35mPa and total tensile load 1050 kg.

Hoop stress at design pressure (2500kPa) I get sigma 175mPa and load 53.535kg

Where I'm running into trouble is backing that data into the tenacity/breaking strength of the material to select thickness of the webbing

Hey engineers! I am not an engineer, but it is a pathway I am very interested in. I love CAD design specifically. Enough about me though, I wanted to know if any of you all had any engineering “problems” you’ve had to solve. I want some real world situations that I can practice coming up with cad designs or modeling already thought out ones. Thank you all!

# Overview

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Operators 100% inspect clear syringes filled with a water-like fluid. They use a white/black background with a 2000 lumen black light.

We ran a gage RxR and roughly half the operators failed, the other half got 100% accuracy.

I'm repurposing some large 10,000lb cast steel weights for a project. They were in a deadweight transducer calibration frame, so I know they were 10,000lb (at the original location's gravity). They're very old, 1960's ish.

Considering the parts' dimensions, I'm getting 0.26 lbf/in^3 (7.19 g/cm3). The porosity of this weight would be 8%. Is that something you would expect, or am I missing something?

I have a little aluminum casting knowledge, but none with steel. Modern aluminum casting for industry uses lots of technology to keep porosity to ~1%.

I realize the material and the times have changed, so it may be perfectly normal. Just trying to sanity check myself before continuing.

Any casting engineers in here care to shed some light?

Really? This is a thing now? FFS

I'm looking to seal between an aluminum flange and a PCB assembly that will pass thru the flange. This will act as a vacuum sealing barrier, and hopefully operate just fine down to 10^-7 mBar. Of importance for is low outgassing of the epoxy after curing (think NASA low outgassing, ASTM E595).

Does anyone have any recommendations?

# 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

​

1. **Before asking any questions, consult [the AskEngineers wiki.](https://new.reddit.com/r/askengineers/wiki/faq)\*\* There are detailed answers to common questions on:

* Job compensation

* Cost of Living adjustments

* Advice for how to decide on an engineering major

* How to choose which university to attend

​

1. Most subreddit rules still apply and will be enforced, especially R7 and R9 (with the obvious exceptions of R1 and R3)

​

1. Job POSTINGS must go into the latest [**Monthly Hiring Thread.**]((https://www.reddit.com/r/engineering/search?q=flair%3A%22hiring+thread%22&restrict_sr=on&sort=new&t=all)) Any that are posted here will be removed, and you'll be kindly redirected to the hiring thread.

​

1. **Do not request interviews in this thread!** If you need to interview an engineer for your school assignment, use the list in the sidebar.

​

## 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 am trying to calculate the force required to push a stainless steel cuboid through a hole in another cuboid of neoprene rubber and can't seem to find a good formula to calculate it with.

The data is as follows: It is a stainless steel cuboid of 0.04" (1mm) by 0.04" (1mm) by 0.32" (8.25mm) deep, the hole cut in the rubber is 0.023" (0.6mm) by 0.023" (0.6mm) by 0.32" (8.25mm) deep, it is a rubber cuboid of 0.197" (5mm) by 0.197" (5mm) by 0.32" (8.25mm). The exact material is ultra strength neoprene rubber with 70A durometers, 2,500 psi tensile strength, and a tolerance of -0.020" to +0.020" at 1/8" (0.125").

T.L.D.R. ——-(Basically the steel is larger than the rubber by a margin 0.4, how do I calculate friction?)——-

Suppose that the rubber cuboid is fixed surrounded by a steel rectangle.

How much force in Newtons would be required to push this rod in accounting for friction and all, and what would be the formula to calculate it?

Also, what would be the optimal shape if other than a cuboid to generate the highest amount of friction and therefore require the most force to push it in?

Thanks! Hoping this enlightens me and others because I couldn't find a way to calculate this.

I double majored in comp sci and accounting and am trying to self-teach myself engineering. I got some (older) textbooks from thriftbooks to give myself a bit of a crash course on just general stuff.

Here is a list of the general subjects i got books in and the years that they are and I just wanted to make sure I wasn't going to read anything super outdated even though I am pretty sure alot of mechanical engineering has been set in stone for a very long time.

Fluid mechanics (2005)

Mech E design (1988)

Dynamics (2001)

Thermodynamics (2010)

Mechanics of materials (2012)

Machining fundamentals (1993)

control systems engineering (2000)

If im missing anything that is going to give me a gaping hole in my general knowledge which I probably am can yall let me know

Thanks

I have been making smart devices with ESP32 boards, sensors, relays, LCD screens, etc. Recently I made my own smart thermostat for a natural gas heater in my detached garage. I design and 3D print my own cases and enclosures for these devices. I'm learning how to use KiCAD to make my own schematics and eventually make my own PCBs. I use SolidWorks and Inventor to make my designs. I code everything myself. I also have been dabbling with resin casting by making 3D printed molds and things out of silicone and urethane. I haven't sold any of these things or designs to anyone yet so I don't think I can consider myself an Inventor. Am I a "Maker"? Most of these things I've made are for my own enjoyment, or to make my life easier. A lot of times I just experiment to learn a new skill.

Hi folks,

I wrote a handbook on discrete-event simulation with SimPy, designed to get you building simulations using Python. Kind of like the official documentation but on steroids.

I have used SimPy for over a decade. Discrete-event simulation is useful for modelling real world industrial systems such as factories, mines, railways, etc.

My latest venture is sharing my know-how on how to do this.

If you do get the handbook, I’d really appreciate any feedback you have. Feel free to drop your thoughts here in the thread or DM me directly!

Here’s the link to get it: Handbook Link

For full transparency, why do I ask for your details?

Well I’m working on a full programme which will be all about real-world modelling and simulation with SimPy, and I’d love to send you keep you in the loop. If you found the handbook helpful you might be interested in the programme. That said, you’re completely free to hit “unsubscribe” after it arrives if you prefer.