This kind of math is where those multipliers come from! If you want to design the thing & tell me what to do have at it. Ron Stewart from Knoxville, Tennessee on October 13, 2013: I been doing electrical work for about 35 years. For example, if you had from left to right, 1/2" pipe and a 3/4" pipe, the offset on your 1/2" starting at 24" and you were bending 30 degree bends for a 6" offset, and you wanted 1" between your pipes, you'd make the following marks, measuring from bottom up. Although it is stamped on every bender I've ever seen, just as you say. And yes, math and its associated items (reading a tape measure perhaps) is very important and for someone that has no training in math at all even simple addition or subtraction of fractional figures can be difficult. When bending a 3 bend saddle , my mark A is 30 inches and im crossing a 3 inch object then what are my measurements for mark B and C. Dan Harmon (author) from Boise, Idaho on February 23, 2014: 10 degrees rise per inch = .08". Thanks for this easy to understand site. Recommended for Android phones is the RealCalc scientific calculator app, available from the Google Play store at no charge. But i still find myself coming back. Question: I'm trying to bend a 10 stick of 4 EMT in the centerline of the conduit so I can get equal lengths on both ends. I need to have 80" in the middle, with a 90 on each end. All wiring must be in metallic raceways, so bending conduit is one of the first things every apprentice learns. Question: How do I determine set and bend permissible radial length for bending conduit or electrical pipe? The last bender that you selected will be the bender that appears when you open the app up again. Some of the math is already built into a common hand bender device, and the rest of it involves the geometry of a triangle. This is all assuming that the pipe is a pencil line, not a 3-dimensional object, which we know is not true. It is very important to get the two marks at exactly the same place on the bender, and it isn't always easy with big pipe. The "length" of the bend is then 4.5", but the length of pipe used to make that bend is 3.14*4.5/2, or 7". 1/2" pipe Mark 1 at 24", Mark 2 at 36" (offset height, which is 6" x offset multiplier, which is the cosecant of bending angle, which is csc(30), which is 2, therefor 12" between marks) Now, for the 3/4" pipe, we take the O.D of the pipe, which we'll say is an inch and an eighth, and we add it to the distance we want between pipes, which is 1". Dan Harmon (author) from Boise, Idaho on January 30, 2015: Thank you, Steven. After they master these, I will then show them more bending techniques and formulas. My undergraduate degree is in applied mathematics and I often make the mistake of assuming that my new hires are equally versed in trigonometry. Dan Harmon (author) from Boise, Idaho on December 14, 2013: Not bad, although a few of additions need to be made. QuickBend is the quickest and most accurate conduit bending calculator app.QuickBend is an advanced conduit bending calculator that was created to be fast and accurate while being visually appealing, innovative, and intuitive. GREAT WRITE UP!!! I would have more trouble remembering Sohcahtoa than I would the formulas! Makes life easier and prevents math errors. I am so pleased and happy when I came across this site with or sincerity, I was glad. Wiring homes, for instances have little to no conduit bending. I can't remember for 3" pipe, but often a different shoe works very well to set under the end of the conduit to level it. Have you picked up an error elsewhere in the article that I missed when proofreading? Yes, the very word ("math") scares a lot of people off, but it really isn't hard. It helps so much to know where things need to go. Only a few numbers and math operations need to be memorized to make offsets, saddles and 90 degree bends. I'm grateful to you and your work, from here in Canada. Please verify if my calculations are off or if I am missing something, I never took trig but my calculator did and I can recreate your results on paper with it but the multipliers don't seem to be working.. Dan Harmon (author) from Boise, Idaho on March 06, 2012: ?? How do i figure out the bends and degrees for an existing conduit to match without removing the emt or rigid? This is a lot easier to understand if you draw your pipes first so you can visualize how your marks will be moving on each subsequent pipe. This app works great and is very accurate. Your easy to follow explanations, pictures and images really helped it make sense. 2022 The Arena Media Brands, LLC and respective content providers on this website. Stuff. He finally decided to weather the awful process of my 'math' usage, and sunnuva'gun if he didn't ask me later if I would go over some of the fine points with him , etc. My green helper can now bend pipe better then the old timers and I love it! From my understanding I'm going to learn about electrician tools, wiring, how to wire up motors, PLC n controls, power distribution, electric codes, blueprints schematics, electronic component circuits, a little construction, and how to bend conduit. This app allows an electrician or apprentice to select values for offsets and saddles and be presented with the figures to assist in making a professional installation. As you say, start simple and go from there and the math in this hub is not where to start. These are just the relationships between the sides of a right triangle; they depend on the angle (d) of the triangle. Why not just use the star on the bender rather than the arrow? ), an inaccurate or poorly placed protractor, etc. 160 (they also reference the wrong page which brings you to hand signals, ha,ha). I applied this to bending rigid ocal, and it got me pretty darn close. How can i know the different take off of degree of pipe using tangent. There will be some "shrinkage", which can be found by the math formula of Shrink=4.25-4.25*cos(22) = .31" in your case. The Arena Media Brands, LLC and respective content providers to this website may receive compensation for some links to products and services on this website. Dan Harmon (author) from Boise, Idaho on May 01, 2012: That's my guess, as I said - you simply overbent it just a little. I need to know how to figure it out. Very few beginning electricians are taught anything beyond the most basic instructions for bending electrical conduit pipe (EMT, electrical metallic tubing). You would have to check in practice, but I suspect that the NEC figure is to the inside of the bend, meaning that the loss will be 3/4" less than what is calculated: the length of the completed bend will be 3/4" more than the minimum radius. Once bent, treat it as if it were an offset using the same multipliers as you would for bending an offset. This is great and wow Love it so much very educating. Michael Willis from Arkansas on December 31, 2010: One of the hardest things to teach to "newbies" can be conduit bending if they do not understand math sometimes. And now that we have smartphones, the calculator isn't just cheap; it's free. Dan Harmon (author) from Boise, Idaho on November 28, 2011: I'm not sure I'm understanding your question, but let me try. I want to study more so as to know more. It doesn't matter what size pipe it is, nor what bender it is - the trig works for any and all pipe size or bender. This means that 1.25 inches is pretty close to half the OD of a 2" pipe; they are probably measuring the minimum radius at the center of the pipe rather than choosing either the inside or outside of it. The problem is that the radius of the bend varies with the size of pipe so instead of using the bender to determine the radius it must be matched to that of the largest conduit. - Joslin ( Detroit ). This article is accurate and true to the best of the authors knowledge. I figured a 5 1/8" to drop with 22 bends 2 1/8" if that is right, didn't write it down when doing it but I'm not sure what to add to account for the loss in the bend. I always wondered how some of those pipes were bent in such a precise way. Normally, this would be impossible using a 10 bend, as two bends cannot be made that close together (12) in a conduit that large. Brought back memories from trig. Got everyone at work to download it. Hahahahah. QuickBend supports the following bends. Offset Rolling Offset Matching Bends Offset Matching Centers Offset Parallel Offset Three-Point Saddle Four-Point Saddle 90 Kick With 90 Matching Bend Kick Matching Center KickParallel Kick Multiple Parallel Kicks Compound 90 - Circle Obstruction Compound 90 - Rectangle Obstruction Compound 90 - Square Obstruction Segmented 90QuickBend Benders Cosecant (Okay. Dan Harmon (author) from Boise, Idaho on June 05, 2012: Thanks, cablemanagements. I simply got curious one day and put some of my college math to work - it's been useful ever since. There is no deduct except when doing 90 degrees on a hand bender. Love this app and have been using this for several years. While this is not usually important in smaller conduit, it most definitely comes into play in the bigger stuff. I've never found it necessary to measure closer than 1/8" in the field so it works fine there. Shrinkage of an offset is the difference between "b" and "c" in the first diagram. What is the shrink per inch of rise for 10 and 60 degree bends ? I tried 22 degrees as close together as possible, it was over 9 inches. Two examples of angle finders from Amazon are shown below. A long pause followed. for a memory aid: Chief Sohcahtoa S= O/H C=A/H T=O/A, probably works for me since I'm Cherokee ;-). In the final analysis it will always be necessary to round off and simply choose the nearest fractional equivalent to the calculated decimal figure. But you can block it in and print it that way. I have tried using these calculations to recreate the results I had at work today. Point me to how we deturmine the deduct for a bend. And, yes it's an example in ugly's from the 2011 edition pg. 22 degree is around 2.4. So, 60\17 = 3.5. The "loss" is then 7-4.5, or 2.5". Nevertheless, learning how to bend conduit to very nearly any angle you want is not difficult. It is critical that the pipe be really horizontal, at 0 degrees; check with a level. See and edit your bender's information (Center-line Radius, Deduct, Gain, Setback, Travel, and Radius Adjustment) within the 'Bender Specs' section. shrink = hypotenuse(offset bend marks) - cos of angle X hypotenuse. The mark on your second pipe will be moved based on the distance between your pipes and the diameter of your second pipe. I've heard ppl say that AC theory n conduit bending are a bitch. Note that making concentric bends requires using some additional math not discussed in this article. Are you referring to an example in Ugly's? Question: How do I figure out how to match 90 degree bends with different size pipe? I actually do enjoy sharing my knowledge and work tips with others. Dan Harmon (author) from Boise, Idaho on September 23, 2013: Knowing electric codes is huge. The "B" bend is not at the same point on the bender, but at the center of the chosen degree for the center bend. Dan Harmon (author) from Boise, Idaho on November 15, 2016: Thank you, Jeffery. Question: how do i figure out the development for a 15 degree saddle bend if the center line radius is 25"? I enjoyed your article, particularly the comments. Great info. If you're making another pipe to fit onto a rack next to the 2" pipe, it will have to have a radius of that figure plus the distance between pipes (plus half it's own diameter, of course). Note that this can also be written as C = A * (1 / sine(22)). This leaves the pipe horizontal, with the end being bent upward. I found your explanations of the calculations easy to follow and I have sent links to your articles to all of my employees. See https://dengarden.com/home-improvement/a-conduit-b for complete instructions for saddles. You're on the right track here, and your math is correct - you even caught that the multiplier for 10 degrees is not 6, but actually 5.75 (6 is just a usable figure that is easy to work with). Dan Harmon (author) from Boise, Idaho on July 15, 2018: Not sure I understand the question. The formula is (distance between pipe + diameter of pipe) x tan(half the offset angle). I'm glad I found your blog!! In real life, of course, conduit is not a one-dimensional line, but rather a three-dimensional object with curved, not sharp, corners. ) Current Tools: 750/751 Current Tools: 77 Current Tools: 747 Gardner Bender: Big Ben Gardner Bender: Sidewinder Gardner Bender: Electric Sidewinder Gardner Bender: B2000 Cyclone Gardner Bender: Ultra Eegor Gardner Bender: B300 Series Greenlee: Hand Benders Greenlee: 1800/1801 Greenlee: 1818 Greenlee: 555Greenlee: 854DX Greenlee: 855GX Greenlee: 881 Greenlee: 884/885 Ideal: Hand Benders Klein: Hand BendersQuickBend Multiple Bends Layout multiple bends on a single stick of conduit. Offset to ObstructionOffset from ObstructionThree Point Saddle Four Point Saddle 90 Bend, Kick Kick with 90 Place a cut mark for those rare occasions that you need to cut and thread the conduit before bending. Flip bends around. Graphic representation of where the bend/cut will layout on a stick of conduit. Bend layouts are based on your benders centerline radius, deduct, and gain. Toggle 'Measure to Centers' to help line up conduits when working on raceways with multiple conduit sizes.QuickBend includes a protractor level which is easily accessible and can be Zeroed by a simple tap.QuickBend allows you to pick between either form of measurements, imperial (inches) or metric (cm).QuickBend's QuickCheck indicates if bends are impossible by a subtle change of turning the measurements and text red.QuickBend's center-line radius algorithm is especially useful when bending conduit that is larger than 1 inch and bends that exceed 30 degrees.If you'd like to make any suggestions or just want to say 'hi' please e-mail me at rigidpro@outlook.com, Parallel Kick Multiple Parallel Kicks Matching Bends Offset Matching Bend Kick Performance Improvements Improved GUI Milwaukee Hand Benders Greenlee 882 Hand Benders can now select rigid conduit Bug Fixes. but i know i wouldn't use them in the feild. HubPages is a registered trademark of The Arena Platform, Inc. 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Dan has been a licensed journey-level electrician for 17 years. Thanks for the comment - it's nice to know I was able to be of assistance. Dan Harmon (author) from Boise, Idaho on November 19, 2012: @Mike: yes the multiplier of a 30 degree offset is 2, that's what is in the chart above.
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