What thickness steel can you roll (for a cone) without special tools?

[julianf]

Im thinking of trying to do myself damage with the welder again, and am considering a twin coned (for water heating) drum as a project.

There's a steel place within walking distance here - wondering what thickness i would need to have hope of forming the cone without fancy stuff?


Ahh, thinking about it, i have a metal break that ive never used (due to not having a work bench to bolt it to at present.  I dont know if that would help?

[Rotary-Motion]

funny you mention a cone i been thinking of this for a while now, but never really gone round to it as i dont need one hehe, doesnt stop me thinking about one though and the how to get it to a cone...

[bertle]

Well I would say 0.9 you can just about pull it round your knee. 1.2 if you are strong enough, but really you are going to need some sort of tool. Now you could probably get it with a big diameter ball ended mallet and a sand bag if you are carefull, or any device which will produce a straight bend will do it. 1.5 and you are pushing your luck, you need rollers or a press brake I would say.
This is advice given by someone who works with metal although I am no "tin basher" in the hammer and dolly kind of way.
I expect that Jim will be along to tell you he can beat one out of 1/4" plate in a bit but we are mear mortals and have to bow to his skills.

[Rotary-Motion]

this is my take on it, get a square bit of metal (bigger than the drum or tube) draw a circle, cut a hole in the center (ball valve fitting) cut a section out aswell (like a slice of cake) and the outside the big circle bits, then drop in into a old car tyre to start the cone going by pulling the 2 sides together (wedge shape cut out sides) maybe standon center push it down, if too stiff make something to jack the 2 lines together, could leave 2 lugs of metal on to help pull it together? hold with malgrips and weld the sucker...

pulling 2 sides together will create a cone shape

maybe use a clamptop lid clamp to hold it to size to weld slice of cake line

try it with a bit of card first

[greasemonkey]

I think I made mine out of 0.6, and intend to do another one very soon.
It was not difficult to bend, but I wouldn't have wanted it much thicker. I think with 1mm it would be a bit of a struggle to bend it around your knee without over bending it in one spot. 0.6 is plenty strong enough, in my mind, for the average settling tank, processor application.
There is the added advantage with going a bit thicker, that is is just that bit easier to weld.
I don't know if I will do it or not, but it would not be a major project to make a simple bending machine.

[julesandtash]

I have done a couple with 1.2mm steel sheet (because the local scrapyard had a load in going cheap)
I cut it as per the pretty diagram above except I added a extra bit on one side of the pie slice to make an overlap weld.
I then used a piece of steel pipe as a former and slowly worked my way around standing on the pipe and pulling the edge up a little bit as I worked around.
By the time I got to the end, the two edges were pretty much touching and it was just a case of pulling them in and putting a couple of tack welds in place then welding the seam up.

Clearly not as nice as one of Jim's but then I am no sheet metal worker.

[Rotary-Motion]

nice one jules, where theres a will theres a way fo sho...

 

[bertle]

The most important thing is to get the dvelopment right and cut it out accuratley. If you have the correct amount of metal and can pull it round well enough to get the ends to touch so it can be tacked, you can then tack it to the drum and it should come right. The important thing when tacking to the drum is to split the circumferance up into quarters. You then have your first four tack points, this helps to minimise the accumulated error you would get if you started at one point and just worked round, you would find that as you got back to where you started you would have far too much or not enough metal.

[Rotary-Motion]

good pionts, i would of got the errors...

[greasemonkey]

The most important thing is to get the dvelopment right and cut it out accuratley. If you have the correct amount of metal and can pull it round well enough to get the ends to touch so it can be tacked, you can then tack it to the drum and it should come right. The important thing when tacking to the drum is to split the circumferance up into quarters. You then have your first four tack points, this helps to minimise the accumulated error you would get if you started at one point and just worked round, you would find that as you got back to where you started you would have far too much or not enough metal.

Precisely the cock up I made on mine..........

[Jamesrl]

It would be simple enough to shape a cone cut from 1.5mm steel thus making MIG welding easier, I use my knee to shape my cones.

To work out a cone very accurately use, included angle = 180 x diam / slope length.

Any one can work out or develop a cone, shaping it is where the skill is.

[Julian]

All this talk about cones ... don't forget that Tony put together this calculator ... http://www.biopowered.co.uk/forum/tools/cone.php

[julianf]

It would be simple enough to shape a cone cut from 1.5mm steel thus making MIG welding easier, I use my knee to shape my cones.

To work out a cone very accurately use, included angle = 180 x diam / slope length.

Any one can work out or develop a cone, shaping it is where the skill is.

Are you saying that its simple, or that its not simple?

To quantify - In your option, for an average mortal.

[Jamesrl]

It would be simple enough to shape a cone cut from 1.5mm steel thus making MIG welding easier, I use my knee to shape my cones.

To work out a cone very accurately use, included angle = 180 x diam / slope length.

Any one can work out or develop a cone, shaping it is where the skill is.

Are you saying that its simple, or that its not simple?

To quantify - In your option, for an average mortal.

Ah, a poor choice of words Mr Mortal.

The actual manipulation of the metal would be easy because of it's physical size, knowing where/how to start and what to use to aid the shaping, remembering it's being done in a shed without rollers, press etc. is where the skill bit comes in.

Any truly skilled craftsman will make his trade look easy. 

[julianf]

Right - an "easy when you know how" one then! : )

Wanna give me a step-by-step?