Need to make a cone

[side-show-bob]

Hi all

I need to fabricate a cone on the bottom of a litre metal drum, i have calculated the pattern but now i am unsure how best to proceed with out any rolling equipment.

I am wanting to use 1.2mm mild steel, would it work if i started tacking it to the bottom of the drum, would the tacks hold it as i pulled it round to form the cone?

Any advice greatly received

Thanks

 

[pedrobedro]

Get some 25x3mm strip and make a ring to fit the drum base then tack the cone to that just to give it a bit more anchorage.

 

[gordon stephenson]

Without any rolling gear I would mark off the base end of your development every inch or so and carry on these marks up to the point of the cone, then bent a little at a time between angle-irons in the vise etc, Don't think you will succeed by just tacking and trying to pull it into shape.

 

[cumbriasteve]

You could maybe bend the bottom as you tack but the top would not follow, too much tension over a small area, in the old days when my memory was still with me we used to mallet the cutout over a bit of angle, you need to taper the end of the angle to fit the cone end on, work away tapping and bending at about an inch a time.
Gordon has detailed a similar method that will do the job the same.

 

[Hitch]

Sheet that thin, and i assume its only around 3-4" diameter, mallet it round.

 

[side-show-bob]

Sheet that thin, and i assume its only around 3-4" diameter, mallet it round.

It is 23.6" top and 2" bottom do

 

[rockjock620]

Hi all

I need to fabricate a cone on the bottom of a litre metal drum, i have calculated the pattern but now i am unsure how best to proceed with out any rolling equipment.

I am wanting to use 1.2mm mild steel, would it work if i started tacking it to the bottom of the drum, would the tacks hold it as i pulled it round to form the cone?

Any advice greatly received

Thanks

If you have drawn the pattern out (and it's basically only a very simple technical drawing) then transfer that to card, draw a series of straight (spoke like) lines on the card, transfer them to the metal, score them (I would use a slitting disc in a grinder on 1.2mm0 and fold along the lines. That will give you a segmented or faceted cone shape, much like the faces of a diamond stone would look, or if you want it properly round then you WILL need rolling equipment.

 

[Paul.]

Forming a cone or cylinder in light materials is easily done with a piece of tube or round bar clamped to the bench with a couple of packers under,


Mark out your cone development using felt pen or similar with some bend lines that converge on the apex of the pattern to give a guide to the axis of the bends, then set the ends using a mallet.


Then turn it over, slip it in the gap under the tube and gently ease it round by hand, keeping the pen lines in line with the former, when you get halfway turn it round and work from the other edge.


Don't try to do too much at once, several passes are better, here i have changed the former tube for a smaller diameter to finish it off.


The finished item ready for welding, all hand formed.