Making tee joints in pipe

[Furry Freak]

I wonder if I could tap into the knowledge bank once again. I'm after any tips for making a neat mig'd 90 degree joint in round pipe. Say I take a piece of 1" tube, cut a piece off and try to weld it back onto the body of the tube, there's an obvious gap between square and round. Clearly I need to round the end of the piece of pipe to the same as the OD of the main pipe. And that's the issue. I may need to do this a dozen or so times. If I was adding a piece but using flat, I could cut it with a hole saw and the cut across the hole leaving me with two pieces with a cut out - yes? But with tube, I would most likely go off to one side and make a right mess. So how do I approach this. The job itself isn't important, the question is pretty universal.

Make sense?

Thanks in advance

FF

 

[busa]

You can actually use the holesaw method if using a pillar drill and suitable vice. Alternatively for a 90* Tee joint, cut the tube at 45*, rotate it 180* then cut it again at 45*, cut off the two resulting points and dress up with a half round file, this will leave a good tight fit. After you've done a few joints this way you will find it easier and quicker than messing with holesaws.

 

[Furry Freak]

Yes, now I like that idea. I hadn't thought of it like that. I think that the hole saw route in my drill would be arduous, but on the chop saw, it would be fine. Especially if I made up a little jig to get it the same each time.

Thanks for that. It's a good start.

FF

 

[rory1]

when you get the right angles make a pipe wrap out of a bit of card or plastic, cut it to the right shape so you can draw round it on the next one you do.

i did have a link for a little programme you can download called tube miter which gives you pipe wraps you can print out. cant find it for the life of me though, im sure someone else will know where to find it?

 

[Paul.]

Here you go, clicky,
You also might want to read through this thread

 

[hotrodder]

chopsaw/bandsaw method including a link to an online angle calculator. Metalgeek has an online 'pipe wrap' calculator but some others were posted when this topic was discussed a little while ago

D'oh, must refresh page!

 

[Furry Freak]

Thanks guys, I found some of the earlier threads on here simply by using Gurgle to look up tube-miter. It lead me straight back to here! Got some good tips now. The application would be useful, except that I use a Mac. I wouldn't give a PC house room. I shall see if I can get a Mac App to do this. Some really neat looking joints on here. All I need to do now is weld them neatly myself. Ahh another flaw in the plan, eh?

Thanks everyone

FF

 

[KTMMICK]

Thanks guys, I found some of the earlier threads on here simply by using Gurgle to look up tube-miter. It lead me straight back to here! Got some good tips now. The application would be useful, except that I use a Mac. I wouldn't give a PC house room. I shall see if I can get a Mac App to do this. Some really neat looking joints on here. All I need to do now is weld them neatly myself. Ahh another flaw in the plan, eh?

Thanks everyone

FF

I think you will find if you cut an angle of 30 degrees you will be just fine.......from both sides...that's how I do it. Ooooooooops misread the thread, 45 degrees is the may to do 90 degree joints if you have a chop saw should be a piece of cake.......make sure you cut them shorter than you need so you have a gap to fill........better penetration that way. Oh I am a plank......you do want 'T' joints first part of this reply applies..yeah I could of deleted my mistake but thought it would give you all a laugh

 

[BillJ]

I recently did this with some small tube (12x1mm) and found by experiment that two opposing cuts of about 30 degrees worked quite well. I had a suspicion that 30 degrees wasn't perfect but it worked well enough for me so I stopped experimenting there. Then someone mentioned on here that (I think) 33 degrees was the magic figure and that sounds reasonable.

 

[KTMMICK]

I recently did this with some small tube (12x1mm) and found by experiment that two opposing cuts of about 30 degrees worked quite well. I had a suspicion that 30 degrees wasn't perfect but it worked well enough for me so I stopped experimenting there. Then someone mentioned on here that (I think) 33 degrees was the magic figure and that sounds reasonable.

30 degrees does work I think......but because it is cut straight it does leave a small gap, not enough to worry!

 

[busa]

Yes, now I like that idea. I hadn't thought of it like that. I think that the hole saw route in my drill would be arduous, but on the chop saw, it would be fine. Especially if I made up a little jig to get it the same each time.

Thanks for that. It's a good start.

FF

Doing it on the chop saw is a breeze, I have a stop which clamps to the tube and butts up against the back of the saw vice, it has a short piece of flat bar so I can use a small level to set the 180* rotation. With a little imagination something similar can be knocked up out of scrap. Regarding programmes such as tubemitre, if you are working with small diameter tube, inch and a quarter or less, in the time it takes to fire up the computer, generate the wrapround, cut it out, etc you would have the notch marked and cut by hand. Hand cutting notches is one of those jobs where you shouldn't compromise on tools, you need a good hacksaw, with good quality blades and a selection of good quality files. If you use a cheap market stall blade then after a few strokes it will have less teeth than your grandmother, and cheap files will be tedious to say the least.

For angles other than 90* on same diameter tubes, draw the tubes out at full scale on paper at the required joint angle, draw the centrelines of both tubes also. Draw two lines from the point where the centre lines cross to the points where the sides of the branch tube meet the main tube, you can now see the required cut angles. This is by no means an exact science as it does not take wall thickness into consideration but it will be near enough to dress up into a pretty close fit.

 

[Welderpaul]

One to watch for if you are welding up a tee joint in tube - all the welding is carried out on one side of the tube. This will have a tendancy to bend the tube towards the weld. (The process of welding shrinks the tube on one side as it cools). May be wise to clamp it to reduce distortion.

 

[hotrodder]

With the chopsaw/bandsaw/hacksaw method the angles change depending on the diameter(s) of the tubes. The first link in my last post explains, there's also a link to an angle calculator in that thread

 

[Blackjack]

With the chopsaw/bandsaw/hacksaw method the angles change depending on the diameter(s) of the tubes. The first link in my last post explains, there's also a link to an angle calculator in that thread

OK, I have to ask, have you ever actually tried this?

Because whenever you're joining tubes (or pipes) of equal diameter, the angle of the intersection between the faces is ALWAYS 45 degrees...

If you were to draw it out, then changing the OD of the tube would only be a matter of changing the scale of the drawing not the angle of the intersection.

Look, this is particularly awful, it has some fairly large issues, the sound is frankly awful, and I'm not overly happy with it...

But, FWIW here's a link to a video

http://www.thefont.info/video/Tubemitring01.wmv

After I made that I went out and bought some new hacksaw blades, and a new file, without the jabber, with the new tools, one mitre, one minute and twenty three seconds...

The 1/3 thing works for the sort of wall thicknesses I use, guys who use thicker wall tube, tend to use 1/4 rather than 1/3 for the cuts.

 

[wyn]

A good point on your vid, Blackjack, is getting rid of the "feathered edge".
When i use a holesaw on tube it leaves a lot of this edge that has to be ground off to get back to enough tube to weld to. By the time this is done the joint looks the same as if it had been done with a band/hacksaw.

 

[hotrodder]

Yep, i have (and will continue to) use all the methods discussed so far including the one you used in your video. They all have pros and cons to them (jmo), the method i go with for a particular joint depends on the angle the tubes intersect at, material, wall thickness, the mood i'm in etc

The chopsaw/bandsaw method i linked to... can't really explain it better than that thread does. The angles are different because cuts are made to the centreline of the tube. If i get the time i'll make a couple of joints using that method tomorrow and post some pics

To add to the tips mentioned about distortion and the feathered edge, don't forget to drill a breather hole when a tube is welded at both ends. Once the tube has been fitted the hole can be hidden inside one of the joints

 

[Blackjack]

The chopsaw/bandsaw method i linked to... can't really explain it better than that thread does. The angles are different because cuts are made to the centreline of the tube. If i get the time i'll make a couple of joints using that method tomorrow and post some pics

I've seen it before, and this is the bit I have trouble with..

2.0" to 2.0" tube, base angle of 30 °
1.75" to 1.75" tube, base angle of 28°
1.5" to 1.5" tube, base angle of 26°
1.25" to 1.25" tube, base angle of 22.5°
1" to 1" tube, Base angle of 20°

That's complete nonsense. If you're joining tubes with identical ODs, then then the cut angle should stay the same. The reason it doesn't is that the wall doesn't remain a constant proportion of the OD.

That tells you this method offers a poor fit up and the cut angle needs adjusting to suit the wall thickness of the tube as a proportion of the OD.

It's probably great if you're making railings (but so's squashing the end flat ), not so hot if what you're doing is structural.

If it said something along the lines of...

"An approximation of a "T" joint can be acheived by using this method, where, if the wall thickness is X% of the tubes OD, you need a cut angle of Y degrees, rather than you having to work that out, here's a look up table for some different OD's of tube of around the wall thickness you're likely to be using, increase the base line angle for thinner wall stuff and reduce it for thicker walled stuff."

I think that's what you'd need to do with the angles, but I've only just woken up and I might be visualising it wrong.

Anyway, that would be nearer the truth than saying "this is how you make "T" joints in pipe or tube" which is what it seems to say every time I see that repeated somewhere on the net.

 

[paulmowers]

Hi

Slightly off topic, but in a fabrication workshop where I used to work there was this guy named David and he was their pipe fitter (heavy gauge) and I used to watch him cut out angles and mitres for joints with no marking, freehand with a cutting torch, 45deg, 90deg, any angle, any size of pipe, 2" and upwards. And they fitted with less than 1/16" gap anywhere. It was fascinating to watch him work.

 

[hotrodder]

If we're talking critical structures every method requires a fettle prior to welding. Whether it be to provide a suitable edge for welding or if a perfect, 'daylight' tight fit is required. Even with several grands worth of tube/pipe notcher (milling cutter or belt sander) there will be feathered edges that need to be removed.

First up, 33* degree cuts. Cuts have NOT been cleaned up or even deburred...


Nowhere near daylight tight but gaps are less than than the tubes wall thickness (1.5mm). Change the cut angle to follow the yellow line and the fit changes (36* for the pics below), the apex of the cut will make the fit appear worse but trim the apex and...



Again the cuts have not been fettled, made 2 cuts with chopsaw and snipped the apex back only. For a daylight tight fit up a few seconds with a file or belt sander (as in your vid) is all that's required. As it stands there is a light bevel from the cuts making the fit appear worse from some views. Depending on the wall thickness this may even be of benefit...

I never claimed this was a better method than any other, just another way to notch tube joints as per the OP request

 

[Blackjack]

I wonder if I could tap into the knowledge bank once again. I'm after any tips for making a neat mig'd 90 degree joint in round pipe.......................

................ The job itself isn't important, the question is pretty universal.

Make sense?

Thanks in advance

FF

I guess the point is, the job itself is important.