Notching pipe

[Luck-E1]

Hi all,
I wanted to share a handy tip I learned while working at a chain-link fencing company as a welder. I was primarily a shop fabricator/welder but sometimes had to do field installations for gates, dog kennels, and handrails. We had a hydraulic notching machine that did 1-3/8", 1-5/8", and 1-7/8" OD fence tube and pipe in the shop. Notching (coping,or fishmouthing) in field was done by hand. Most of the weldments were done on 90 degree angles, but there were some handrails that required off-90 joints. This post is for 90's and maybe some slightly off-90's.
Here we go;
I set my bevel square to 52 degrees using a speed square.
http://s9.photobucket.com/user/167luckycharm/media/100_1629.jpg.html?sort=3&o=164

I'm using my craftsman band-saw for this project, but it can be performed with an abrasive cut-off saw. This is where I set the backstop angle with the side of the base as a reference.
http://s9.photobucket.com/user/167luckycharm/media/100_1630.jpg.html?sort=3&o=165

I'm working with 1-3/8" top rail #5 (16 gauge) tubing. Setting a square for the saddle depth plus the margin at the backstop. This measurement is determined by trial and error or sometimes a little luck. A side note about saddle depth; thicker wall material of the pipe to be notched will require a shallower saddle (or notch). The thinner the wall, the deeper the notch.
http://s9.photobucket.com/user/167luckycharm/media/100_1632.jpg.html?sort=3&o=167

This is a shot of the first cut being made;
http://s9.photobucket.com/user/167luckycharm/media/100_1633.jpg.html?sort=3&o=168

Using the same depth that the square was preset to, the second cut is made. Joints that require off-90 angles can be made by altering the depth either with the saw or an angle grinder (trim to fit). To get the second cut exactly 180 degrees apart, I attach a spring clamp about a foot from the end of the workpiece first. Make the first cut with the clamp pointed up, rotate until the clamp points down, lock the workpiece in place, and make the second cut.
http://s9.photobucket.com/user/167luckycharm/media/100_1634.jpg.html?sort=3&o=169

A shot of the finished notch;
http://s9.photobucket.com/user/167luckycharm/media/100_1635.jpg.html?sort=3&o=170

This is what the fit looks like on another 1-3/8" tube;
http://s9.photobucket.com/user/167luckycharm/media/100_1636.jpg.html?sort=3&o=171

Here's another notch on schedule 40 1-5/8" OD pipe;
http://s9.photobucket.com/user/167luckycharm/media/100_1637.jpg.html?sort=3&o=172

After reading up on all the helpful advice from the other members on this board, I felt compelled to share a little something from my own experience.
This is just a basic tutorial. I did a search first but came up with a full list of possible hits that would have taken a long time to sort through.
Aloha from across the big blue pond!
John

 

[Engine]

Thanks for the tips. I need to learn more about notching tubing and pipe.

What do you use for notching in the field? You said "by hand." Do you use an angle grinder with cut-off wheel or chop saw?

 

[Luck-E1]

Hi Engine!
I've been doing this since the early 90's. By now, I've figured out how to do the notches with an angle grinder with a thin cut-off disc, a SawzAll, a Port-A-Band, and a bunch of times I had to use a hacksaw. I think the only times I enjoyed working out of the shop was when I had to fabricate a handrail near a beachfront property. Bikinis everywhere!

 

[C96]

Hi all,
I wanted to share a handy tip I learned while working at a chain-link fencing company as a welder. I was primarily a shop fabricator/welder but sometimes had to do field installations for gates, dog kennels, and handrails. We had a hydraulic notching machine that did 1-3/8", 1-5/8", and 1-7/8" OD fence tube and pipe in the shop. Notching (coping,or fishmouthing) in field was done by hand. Most of the weldments were done on 90 degree angles, but there were some handrails that required off-90 joints. This post is for 90's and maybe some slightly off-90's.
Here we go;
I set my bevel square to 52 degrees using a speed square.

I'm using my craftsman band-saw for this project, but it can be performed with an abrasive cut-off saw. This is where I set the backstop angle with the side of the base as a reference.

I'm working with 1-3/8" top rail #5 (16 gauge) tubing. Setting a square for the saddle depth plus the margin at the backstop. This measurement is determined by trial and error or sometimes a little luck. A side note about saddle depth; thicker wall material of the pipe to be notched will require a shallower saddle (or notch). The thinner the wall, the deeper the notch.

This is a shot of the first cut being made;

Using the same depth that the square was preset to, the second cut is made. Joints that require off-90 angles can be made by altering the depth either with the saw or an angle grinder (trim to fit). To get the second cut exactly 180 degrees apart, I attach a spring clamp about a foot from the end of the workpiece first. Make the first cut with the clamp pointed up, rotate until the clamp points down, lock the workpiece in place, and make the second cut.

A shot of the finished notch;

This is what the fit looks like on another 1-3/8" tube;

Here's another notch on schedule 40 1-5/8" OD pipe;

After reading up on all the helpful advice from the other members on this board, I felt compelled to share a little something from my own experience.
This is just a basic tutorial. I did a search first but came up with a full list of possible hits that would have taken a long time to sort through.
Aloha from across the big blue pond!
John

Hi John,
Nice tip, thanks for sharing and welcome to the Garage.

 

[motobilt]

I have been notching tube using a similar method for many years. I have an abrasive Dewalt chopsaw that I use for notching. Between it and my belt sander I can fit tube really fast. I do use a JMR holesaw notcher as well. I have found when doing the same notch over and over it is much easier to use the holesaw notcher. Thanks sharing your method. Always cool to see what other people are doing.

Dan

 

[hdpusher]

What set up do you use to weld the galvanized?
I recently used conduit to make some goat pens. I used flux core wire with my smaller welder and the welds turned out fine.
Just wondering if you might know of a better/different way? Always seems like there is a lot of bad info on welding galvanized.

 

[rsanter]

Yip. That trick works great
I have done many roll bars that way over the years but I use an abrasive saw.

Now I have an iron worker with a not her as well as my mill

Bob

 

[Luck-E1]

Thanks C96 for uploading the pics. I work better with metal than computer technology.
HD, for gates and kennels that are made of the 16 gauge tubing, I use my Hobart 125 Handler with 71T flux cored wire (0.035"). Works great outside in the breeze and doesn't need the bulky cylinder if I need to do welding away from the shop.
A bit of personal history with galvanized metal. Everything in a fencing shop is made of galvanized or zinc plating. Which is what caused two bouts of bronchitis during my 5 years of indoor welding. After a month of coughing and hacking, blood starting coming up and I finally got to the clinic. Doc said I should consider another career. Bought a lathe, took a couple semesters of machining at the local college, and the boss at the fence company finally opened up one wall of the shop for ventilation. I left the company a week after a hurricane hit in '92. Worked in construction for two years and got hired at a sugar plantation...as a welder. The apprenticeship program was completed 10 months later and I became a Grade 9 Journeyman Welder at the factory shop. Very few objects were galvanized, which was a relief, especially the two years of not welding during hurricane repairs. I still get sick when I weld galvanized metal and get a good whiff of the fumes. I did a lot of welding with stainless and high manganese steels at the plantation. I got sick from them too, but we had a better PPE program in place; ventilation blowers installed, and respirators were worn whenever I had to weld in a confined space. These days, I work at a rum production factory! I still do welding since I'm in the maintenance shop. But I get to MAKE RUM!!!
Thanks for noticing this thread! I'm glad I can help.
Aloha!
John

 

[Sureshot]

I bet someone could come up with a formula using the ID and OD to calculate the depth of the cut.
I had bookmarked some stuff at one time but can't seem to find it. If a person got something simple they could use a labeler and put it right on the bandsaw.

http://www.metalgeek.com/static/cope.pcgi

Maybe someone knows how to get the formula from here. I think it would be a real help.

Edit: I think it would be the point on the pipe where "width" of the OD is equal to the ID of the notched pipe, measure from there to the outside of the pipe. It makes sense in my head but not a good way to explain.

If you set a caliper to the ID of the post and then put that on the OD of the rail it would give you two points to measure from. Put a square against the pipe and use the average measurement to the two points.

Hopefully someone will give the trig formula.

 

[Luck-E1]

My first attempt was to draw on paper the O.D. and I.D. of the pipe, showing an end view and side view with dotted lines as the thickness of the wall. Using a compass set to draw the O.D. of the pipe, I determined the depth against the I.D. of the side view image. Sureshot is on the right track with wall thickness and where it contacts the O.D. of the mating piece. The manual that comes with a Curv-O-Mark pipe marking tool has a page with instructions on how to determine saddle depth. Great for working with larger diameter pipe with thicknesses 1/8" or more. I've seen the layout of the templates available on a bicycle website a few years ago. This is where the dimensions and angles are typed into the calculator, an image shows up, and it can be printed on paper. Simply cutting out the template and wrap it around the pipe for a tracing guide. How the pipe was cut was then done by hand...torch or grinder. I went for the quick and simple method, after wasting several drop-off's from the chopsaw. Thankfully, I still have all my fingers, maybe lost some brain cells over the years but only the weak ones have left the building!

 

[C96]

Thanks C96 for uploading the pics.

Your welcome, I thought it might be a little eaiser for everyone to follow along. The next time I have a tubing project I will give this a try.

Again, thanks for taking the time to share with us.

Has anyone used that tube coping calculator that Sureshot posted with good results?

 

[RedneckWelder]

What set up do you use to weld the galvanized?
I recently used conduit to make some goat pens. I used flux core wire with my smaller welder and the welds turned out fine.
Just wondering if you might know of a better/different way? Always seems like there is a lot of bad info on welding galvanized.

Bad info on welding galvanized- just drink milk, you *****!

Good info on welding galvanized- use a particulate welding respirator at a minimum, weld outside if possible, use fans and plenty of ventilation, fume extractor if possible, powered respirator is also awesome but expensive. When I weld galvanized I try to do so outside, try to stay out of the plume, and I wear a respirator. It also really helps a lot if you take a flap disc and take the galvanized off as much as possible.


There are people who claim breathing in the galvanized fumes isn't harmful but I don't see how breathing in vaporized zinc can not be harmful.

 

[Sureshot]

http://www.mathsisfun.com/geometry/unit-circle.html

Check out the sweet calculator just down from the top marked "Try It!"

So now my head is getting back into this and it seems to be making sense. Good old Pythagoras.

2" OD pipe .250 wall therefore 1.5" ID

Side C will equal 1 (half the OD)
Side B will equal 0.75 (half the ID)
Solve for A.

A squared = C squared - B squared
A = 0.6614

Depth of cut = OD - 0.6614 = 0.3386

To make it more complicated you should add to the depth for the thickness of the angle since you will likely be marking your cuts on the OD. If you have followed it this far though and understand my thoughts both congrats and you will be able to solve for A because B is the wall thickness and you set the angle of the cut I do believe but this stuff was in the first third of my life.

How do you do square on a computer anyway?
If it weren't so late and the end of a very long day I would make a single formula for this and try it. Someone else feel free.

Maybe it could be an app??? or added to an existing one??
Likely been done and I never looked but good to exercise for what is left of my brain cells.


Edit: I did some crunching and it looks like 1.28 times the wall thickness is the proper extra to add to the depth to allow for the angle.