Expert Plumber EXPLAINS How To CALCULATE A Rolling Offset

[@Fargyy]

Just did this in class, good vid. Should do one for offsets going from vertical to horizontal

[@RogerWakefield]

Not a bad idea! Thanks!

[@karlbot4426]

@@RogerWakefieldI think that’s called a complex rolling offset. There’s also compound rolling offsets, which I think are realistically only for welders who can cut custom angles although I’ve heard rumors that in some parts of the country their wyes are cut at a weird angle on purpose to become a compound rolling offset, but I kinda doubt that’s true. I’ve used “swing joints” in the field, but I’d say almost all my rolling offsets were pretty much always setting drains. Where do you find yourself doing rolling offsets in the field?

[@cenation23able]

I’m in Vancouver Canada and taking my Red seal test on Friday, this video really helped me brush up. Thanks Roger!!

[@ryancorcoran465]

Great video! You are very good at simplifying things. Thank you sir.

[@davedeatherage4902]

You've made it easy through you're instructional teaching, I've had folks tell me in year's past they don't need any math skills??? ,. But they do!

[@guitar1301]

Very important to know if going for Master Plumbers licence in NJ

[@karlbaum1235]

Gotta love the simplicity of this video!

[@RogerWakefield]

Glad you liked it!

[@GiovanniGarcia-um3xy]

How can I start beign a plumber?

[@rustyspeake1751]

Great Video Roger Thank you!

[@RogerWakefield]

Glad you enjoyed it

[@Hahaguyz]

When looking for your horizontal measurement do you measure diagonal from the fitting to the a pipe run ? Taking my tradesmen practical

[@DrainMedic]

Great video Roger. The hardest part to the plumbing test for me was remembering all the formulas. Saved this video for sure.

[@jamarleeper8325]

On the Texas Journeyman Exam, they want you to find the travel piece between a 2" cast iron no hub wye and a 2" 45. Which constantwould apply for this example?

[@ringodingo]

The WYE is probably a WYE with a 45 degree branch off of it, right? So you still use the 45 degree constant of 1.414. Of course, your take off on the 45 will be different than for the WYE 45 if that matters for the exam question.

[@carultch]

To get the constant of any angle for a rolling offset, divide 1 by the sine of the angle. Also known as the cosecant of the angle. This is how 45 degrees generates a constant of 1.414 or the sqrt(2), and 30 degrees generates a constant of 2.

[@frankielopez2612]

The fitting takeoff is 3 1/2 inches, but you said to take off only 3 inches? Was this an error?

[@kylealessi7663]

Hello, thanks for the good content. Do you have a video on outdoor faucets and cold Temps? I'm in Austin TX and I'm scared to turn on my outdoor faucet in fears it got busted in our last cold front. I have a couple issues 1. My dog kept on taking off anything I attempted to put on the faucet to keep qarm. 2. Once I was able to keep something on it it seemed to freeze with the freeing rain. It was a sock and a towel with my hose wrapped around it. I live in a one story home on a slab. I believe the water lines are insulated but not sure. The wall the faucet it on is right behind my bedroom. The is a new build home less than a year old.

[@raybrower3180]

For straight offsets there is an easier way than the 1.41. multiply the offset by 1.5 then take off an inch for every foot of offset plus your fitting allowance. A 12" offset becomes 18" minus 1 inch minus fitting allowance. This trick can be done in your head don't need to take time to get out a calculator or write it out. Not exact but within decimals that really don't matter

[@MediocreAccount]

Seems like this would only be useful for offsets greater than 12”

[@TheMustang833]

Hey Roger. I’m a plumber in Garland, Dallas area. I go and take my shop test this Thursday. Is there anyway we could meet and help me with the offset?

[@johnhunt9674]

doing gods work

[@donnielane5094]

so how exactly do you just input the 8"rise and the 12" horizontal measurements? I thought you said you just measure center to center?

[@carultch]

Pipe B, when projected onto the plane of the 8" and 12" dimensions, will "cast a shadow" of 14.4" on this plane. This is what you get from sqrt(8^2 + 12^2). We'd like to make Pipe B long enough between two 45 degree fittings, such that it can cast this shadow on a plane that is 45 degrees from it. A right triangle that is 14.4" on its base, and 45 degrees on its remaining two angles, will have a hypotenuse of 14.4"*sqrt(2), which is 20.4" in length. The shadow is not necessarily literal, and it doesn't follow the exact optics of casting a real shadow. This is more of the mathematical concept of a shadow, which is a mathematical projection of a 3D shape onto a 2D plane.

[@cj0204]

The 20.39 is the total measurement of the travel correct? You still have to take off for your (2) 45s correct?

[@jacobkindsvatter4055]

Plumbob is a very handy tool that takes a lot of math out of the work

[@dennisharvey5852]

What do you Google to get the formulas for angles instead of memorizing 1.414 or 2.613 etc ?

[@AhernMatthew22]

Struggling with IE math, invert elevations. Wisconsin plumbing apprentice struggling w some concepts and work load

[@Dailytruth565]

What was the 42" there for?

[@BBQ_Stick]

for the 45 offset my foreman taught me the tape trick where you multiply the offset by 1.5 and then subtract a 16th for every inch. ex 10" offset turns to 15" and then minus 15/16"

[@gregoryhines7]

How would you calculate A and C on that diagram?

[@patrickguarracino3174]

That how we did it in the paper mill though a maze of piping to hit a cored hole in the concrete ceiling… no room for error 🇺🇸

[@freshcotv8761]

Completely forgot the formula until now needed it last week

[@PlumberWRX]

In the union I use this all the time! Great video Roger!

[@prestonwilliamson727]

Of course you would 🤣

[@RG-27]

Just passed my written exam, and hopefully I be called to go to Austin Texas within a week so i can do the shop test and finally get my plumbing licenses after 15 years in this trade. This video really helped me out because other videos that i watched are teaching us like we are going for our masters degree. I love how you broke it down easily, and im really confident that im going to pass the practical exam.

[@RogerWakefield]

That is awesome!! Good luck on your shop test, let me know how it goes!

[@RG-27]

@@RogerWakefield will do thanks

[@RogerWakefield]

Still waiting to go take it?

[@RG-27]

@RogerWakefield I just received an email, and the closest date is September 10th, so unfortunately, i have to wait 3 more months to take the practical exam 😢. I appreciate you for checking up on me.

[@MrChatty124]

@@RG-27 any updates? how'd it go?

[@danielbot3602]

This works with bending copper too, you just need to know where your bends start

[@27forme2]

cool video

[@Boblol126]

On average, should apprentices have the constants and formula memorized or can this information be referenced somewhere (on the job and in the classroom)?

[@RogerWakefield]

You don't have to have it memorized...just write it down somewhere and leave it in your truck, or somewhere you can reference it often, if needed. 👍

[@alexf6198]

Do vertical offset

[@27forme2]

how do you mean 12 inches vertical and 8inches horizontal?

[@carultch]

Draw an X-Y coordinate plane, such that we are looking straight through Pipe A. Place pipe A at the origin. Define x to be horizontal, and y to be vertical. If you form a 3-d coordinate system out of these axes, the z-axis is the axis of pipe A, which points toward us as we observe from this point of view I'm specifying. Now place Pipe C at a position of x=8 inches, and y=12 inches. If you were to extend pipe C, so that it passes through a plane containing pipe A, this is how far apart Pipe C would be from Pipe A.

[@RogerWakefield]

This community is great! Appreciate everyone looking out for one another.

[@johnmoore1495]

Great video but it would’ve been nice to see you build something using the math.

[@davidg5629]

I knew the 1.414 multiplier to get the length of a 45 degree cut. But I always just throw a tape measure on the work to make sure I end up in the fitting and not just ending up at its face. I almost never use math. Its just not one of my strengths. I'll watch he video a few more times and maybe I'll see what I'm missing. Thanks, Rodger.

[@independentinstallations8419]

Nothing wrong with your method if you get the same results without wasting materials. Its best however to at least have this knowledge as it still comes in handy at times such as estimating materials off site or working on longer runs.

[@alexis21812]

Do I measure from end to end of the box??? End of box to center of pipe??? I notice we got the measurements for just “C” so what about “A”??? This video did not help me

[@williamrutland8097]

How do you figure the size of a gas main into a house?

[@matthewrs7]

When I do the square root of 208 x 1.414, my answer is 17.149 on my Android phone calculator. My Windows 11 calculator gives me 20.392 like in the video. Whats the deal?

[@RogerWakefield]

You using an android

[@travismeek2627]

Check your order of operations and ensure you've landed on the square root. Then, do the multiplication. Don't just plug it it all in at once. I just checked on my android, and it gives me 20.392.

[@davidg5629]

Install your fitting on pipe A, insert a length of pipe, B, in the fitting, then, where pipe B crosses pipe C, hold your 2nd fitting up to both pipes, make a couple of marks allowing for fitting depth, then cut. No math, no errors. If you use formulas you will either be too long or too short. But I use these methods because I just can't do the math.

[@aaronbailey6384]

Lol if you do the math correctly you won’t be wrong either.

[@Allintn22]

So many guys never learn this and or just don't know about it they try to eye ball it or cut it long and shorten it to fit.

[@carultch]

Even this calculation is approximate anyway, because it doesn't account for exact geometry of the fitting. This calculation assumes your pipes and fittings are infinitesimally thin, when compared to the lengths involved. You still will need to shorten the pipe for fine-tuning, if you cut it according to this calculation.

[@user-ns7mz1ld9u]

If you get good at eyeballing it you can put a piece of pipe in faster than you could put those numbers in a calculator. Still good to know the math though

[@Allintn22]

@@user-ns7mz1ld9u I tend to lean toward the eyeball method myself

[@JB-jk3ow]

30 degree is 2.00

[@carultch]

Yes. It has to do with the fact that 30 degrees forms one of your special right triangles. Namely, the 30-60-90 right triangle, which is half of an equilateral triangle. Suppose you draw an equilateral triangle that is 2 feet on each side. Now cut it in half along an altitude line. You create a 30-60-90 triangle, with a 2 foot diagonal, a 1 foot base, and an altitude of 1.732 ft (the square root of 3). Its three angles are 30 degrees, 60 degrees, and 90 degrees. If you were to create an offset/return bend in piping, with 30 degree elbows, it will "cast a shadow" onto the 1 foot base dimension of this triangle. If you know the length of this "shadow", you double it to get the length of the diagonal pipe that casts it.

[@raylafleur6616]

I’m so bad at math

[@drewthousand700]

So much "fun"

[@edwardmarshall2035]

I thought I was the only plumber that watched your videos, but after reading your comments it turns out that everyone calls themself a plumber nowadays.

[@yangashi]

Math, not even once.

[@jorgepadilla5177]

I m sorry but you do not convince me,very confusing your video. What I see there is a rolled offset,one has to calculate the travel of the first triangle that becomes one of the sides of the second triangle and calculate its travel.