Large Design-Bid-Build Projects? I'm currently researching procurement methods for transportation construction projects (such as highways, bridges, etc.), specifically comparing Design-Bid-Build (DBB) and Design-Build (DB). As construction values increase, there’s a noticeable trend toward more DB contracts and delivery methods. The typical reasons stated for preferring DB are its speed, single point of accountability, fixed costs, and the potential for innovation. However, I’d like to dive deeper and explore large-scale projects delivered using DBB. The largest DBB project I’ve personally been involved in was \~$125M, and it was highly successful. What other personal... 2 0 replies
Making a watertight openable buoy Hey everyone! I’m looking at building a buoy (filled with sensors) that can be opened and closed and maintain a water tight seal, I don’t even know the first place to look. Would appreciate any tips, dms, websites, subreddits,YouTube videos or books to read about the topic! Thank you very much for your time!! 2 4 replies
Scroll saws Hi my knowledgeable peeps. I'm looking for a scroll saw to cut 2mm carbon fiber. I can't afford a cnc and don't know CAD. I can't afford a laser cutter that can do the job, so I'm going to use a scroll saw. So far iv found •Delta 40-694 •Dwalt DW788 •Proxxon DS 460 •Hegner multi max 22-v If also found Flying Dutchman ultra reverse blades to use. If anyone can drop some information about these scroll saws\blades for CF It would be much appreciated. Or if you have... 5 1 replies
Ideas on Viewing the Inside an Industrial Furnace My company is doing an R&D project where we need to view customer parts inside of a vacuum furnace that will reach 2100 F in temp and 2 bars of pressure during the heat treat process. Installing a viewing window is very unlikely because we would need to install it on the bottom of the furnace and because of the furnace's make up it would result in severly lowering the furnace's lifespan. Does anyone know if there are any cameras/housing that could handle these conditions inside the furnace or... 3 8 replies
Weekly Career Discussion Thread (27 Jan 2025) \# 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) ​... 3 2 replies
How do Glow Plugs Seal? I am trying to make a seal for a glow plug and I am struggling to find clear documentation on how the seal works. I have found that it is a combination of a o-ring and a tight threading. I have been looking at Bosch glow plugs which are all have metric threads which I don't think have a taper, so I am questioning the sealing ability and I can't find any information on where the o-ring would go. This is the glow plug I intend to use: [https://www.boschsparkplugs.net/bosch-0250201039-80006-glow-plug](https://www.boschsparkplugs.net/bosch-0250201039-80006-glow-plug)... 1 9 replies
Material recommendations for metal strips on paging conveyors? I'm upgrading a bag-feeding conveyor to include an in-line printer (pic below), and in order to keep the bags from shifting while under the printheads I added some tensioned metal strips like many paging conveyors seem to have. First, I tried making my strips out of aluminum, which helped but weren't springy enough. Next, I tried some 26 gauge galvanized sheet steel, which performed slightly better but was too flimsy for lengths over about 6 inches. I'd honestly prefer to just stear clear of galvanized coatings altogether if I... 2 2 replies
Calculating Impact force of tipped cylinder Say you have a cylinder (like one that holds a gas) and it tips over. How would you calculate the force with which the top edge of the cylinder hits the ground? Does the fact it’s moving in an arc change the calculation or is it the same as if it fell linearly? Edit: here’s the data I have to work with The cylinder tipped over and hit the ground from a standing position on the ground. It did not fall off of a table or anything Cylinder weighs... 1 6 replies
Trying to sell pumps, can't find them Does anyone know where i can find this company's website, I am trying to figure out how much this pump is worth, trying to sell it Thanks to anyone that helps 4 6 replies
Question about wind load calculations How do you calculate the final wind load when given these parameters? (Canada) - building importance factor: post disaster, lw=1.25(ULS) and lw=0.75(SLS) - q50=0.58 kpa - Terrain type: open - Design wind pressure: +/-0.92 kpa(ULS), +/- 0.55kpa (SLS) Our subcontractor is saying the resultant load is 40psf, and therefore the specified fencing is no good, it’s with the engineers for review I’m just a busy bee at the GC, but I’m trying to understand how they’re getting 40psf. Are they adding the q50 loading to the ULS loading and... 2 5 replies
Rotary bearing with detent mechanism Hi all. Very very new to all of this. I'm having trouble locating an off the shelf bearing. I'm looking for a rotary bearing with some sort of detent mechanism to "lock" the rotation at 0,90,180,270. It needs to have a 5mm profile or smaller. 60mm in diameter. To be sandwiched between two platforms to allow the top platform to rotate. It will be holding about 350gm. Any ideas? I have no way to manufacture this item. Cheers 3 2 replies
Help Identifying a Pick and Place Machine – Need Advice on Model and Condition Hi everyone, I’m considering purchasing a pick and place machine, but I’m unsure about its exact model and condition. The seller lists it as an SMT-PLC 3 from Madell Tech, which is supposed to be a manual pick and place machine. However, the machine is equipped with NEMA motors on each axis and corresponding drivers, which suggests it could be an automated model. The seller has mentioned that a PC with the corresponding software is included, but they are unable to answer technical questions about the machine. My background:... 5 9 replies
Van Table Steel Frame Design Hey experts, I'm electrical with limited mechanical structural knowledge - so I typically over design my mechanical stuff so much that I know it won't fail. I remember in college - in one lecture on heat transfer, the professor said "I know how you electrical guys do this - you design your circuit, build it, and test it. If it gets too hot, you add a fan." To the problem - below is an image of a table I'm building for my van - with a list of the... 4 1 replies
How do safety standards strike a balance between added costs and the extra benefits of safety. We are all aware of very cheap products that can be got from online retailers that don't comply with safety standards. A lot of the time these products still work and most of the time they don't kill anyone. Adding layers of safety costs money. Ensuring a product complies with safety standards costs money. How do people developing product standards strike a balance between the added cost and the marginal improvement in safety? Is there a point of diminishing returns? Is there an acceptable level of risk (as long... 1 11 replies
Weekly Career Discussion Thread (20 Jan 2025) \# 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) ​... 3 9 replies
What is this Hinge Called 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 3 4 replies
Advice for Making Watertight Clear Cylinder 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... 4 11 replies
Anyone in Industrial Automation? 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? 4 17 replies
2/3 Stroke Linkage Question 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. 3 2 replies
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