Plasma cutters are awesome

[Screwdriver]

If it were me, I'd do something like this:

With a small bracket attaching a string/wire aligned with the tip of the cutter, restrained at 45 degrees to the pipe. The further away the end is tied, the more accurate the cut. I rather suspect a couple of feet and you'd be well inside the tolerance of the cutting process.

I'm sure Maker will be happy to do the calculations ;D

Screwd.

 

[skotl]

Maker is quite correct, good maths today, the variation gets worse the larger in diameter you get. If a notcher is not available, better learn how to develop the transitions.

That was my first thought on watching the notching attempt - I don't have the mental agility to think of things like that!

Interesting view on suitable PPE in those videos, TShirt/jeans/glasses and gloves versus molten metal being sprayed around by compressed air.

And that was my second thought!

 

[Maker]

If it were me, I'd do something like this:

With a small bracket attaching a string/wire aligned with the tip of the cutter, restrained at 45 degrees to the pipe. The further away the end is tied, the more accurate the cut. I rather suspect a couple of feet and you'd be well inside the tolerance of the cutting process.

I'm sure Maker will be happy to do the calculations ;D

Screwd.

I can't understand how that works.
I would get some kind of flexible, heat proofish material and cut out some ellipses of common sizes. You would keep the bit with the hole in it, wrap it around the pipe and trace the torch around the inside.
Like this:

This is for a 100mm pipe but a range of bigger and smaller ones would be good.

 

[CRB]

!!!!Sickipedia!!!!

?Have you not got better things to do with your time?

 

[mr migwire]

I can't understand how that works.
I would get some kind of flexible, heat proofish material and cut out some ellipses of common sizes. You would keep the bit with the hole in it, wrap it around the pipe and trace the torch around the inside.
Like this:
View attachment 60439
This is for a 100mm pipe but a range of bigger and smaller ones would be good.

and here was me thinking you were being a smart ar$£ but you just used google to its full potential,

I prefer using the Mk1 eyeball for my saddles and stuff but each to there own...

 

[Maker]

!!!!Sickipedia!!!!

?Have you not got better things to do with your time?

I haven't been on there in a while as I wont stop myself from repeating what I read and then wozzaaah will tell me off again.

and here was me thinking you were being a smart ar$£ but you just used google to its full potential,

I prefer using the Mk1 eyeball for my saddles and stuff but each to there own...

No, I was just being a smart ****. I'd spent ages trying to find an equation to cope tubes with no luck then last week when I was ill and off school I worked out how to plot an ellipse. All I did for this was work out the right width and plot it on a graphing calculator.

 

[CRB]

I haven't been on there in a while as I wont stop myself from repeating what I read and then wozzaaah will tell me off again.

Off, off, off, off

 

[Screwdriver]

I can't understand how that works.

Assuming two pipes the same diameter, they both intersect at an exact right angle. You could trim the end of one with a grinding wheel at 45 degrees and it would leave a perfect cut for example.

If the cutting head of the torch is connected to an infinitely long restraint at 45 degrees to the pipe, as you move it around it will describe a perfect circle and cut a perfect notch in the end. With a shorter restraint, it will be near as dammit perfect.

If this is potentially of interest, I could come up with a universal jig for cutting (coping?) pipe joints to join pipe of any diameter. Better than the one in the YouTube vid but I wonder how many people would really be interested in such a thing.

S.