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

[Jamesrl]

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

Wanna give me a step-by-step?

Yeh, No Problem,

Left right left right left right left right left right left right left right left right left right left right left right left right left right left right.

[julianf]

...i thought it was all going too well.

[julianf]

Diversions aside -

Looking at Tony's cone calculator, what is the recommended "Desired cone angle from horizontal (a)"

The default value of 30 degrees seems quite shallow?  Im thinking 45 degrees may help more stuff roll down the inside edge of the cone?

Bertle's look steeper than that even -



(the angle at the lower port looks to be less than 90 degrees)

[bertle]

The bottom cones are 45 degrees, it is a bit of an optical illusion but look at the angle between the leg and the cone, that shows it best.The top cones are 10 degrees.

[julianf]

Thank you.

I also just realised how much more efficient cutting them in pairs is -



[attachment deleted by admin]

[Jamesrl]

Thank you.

I also just realised how much more efficient cutting them in pairs is -

Not when it comes to forming the cone.

When forming by hand it's the edges that are the hardest to shape, the main body of the metal forms easily. Making a cone in two parts doubles the edge work and reduces the ease of shaping.

[Julian]

Don't think they are two halves, they are two cones, nested.

[Jamesrl]

Don't think they are two halves, they are two cones, nested.

That may be the case but if you divide the angle you get the halves and one hell of a lot of waste.

With a bit of nesting I can get 6 cones from a 2500 x 1220 sheet.

[knighty]

I think this is what he meant

[therecklessengineer]

If my calculations are correct, then they won't nest like that.

A 30 degree cone requires a cut out of 48 degrees. Nesting in this fashion requires a minimum cut out of 90 degrees.

However, if you increase your cone angle to 42 degrees, then the cut out is just over 90 degrees meaning they will nest - although this will increase the flat circle diameter by 16%.

You could of course space the centres to allow them to nest.


An interesting problem. I'm sure there's a mathematical solution - I might try and find one if I get bored.

[therecklessengineer]

Yeh, No Problem,

Left right left right left right left right left right left right left right left right left right left right left right left right left right left right.

I thought this was a place of sharing knowledge Jim.

I've only made a few cones - and none of big enough to fit a drum, but I can offer my observations from my efforts.

Be as accurate as you can in marking out and cutting.
When you start to bend the cone into shape, make sure you're bending along the cone's axis - bending a little out of the axis will make the cone go squiffy and it won't line up at the end.
Don't try to do it all in one go, bend slowly all the way along each time and slowly pull it into shape. Keep looking at it to make sure it's going the right way. It's easier to correct mistakes earlier on.
As soon as the ends are together, tack the top and bottom before tacking the middle and finally welding along the seam.

[julianf]

The above is a CAD screen shot.  I used Tony's calculator for a 45 degree cone, and copied the values into my CAD application.  I figured i could then take measurements from that as to how to tessellate them efficiently.

[Jamesrl]

I thought this was a place of sharing knowledge Jim.

The reply was supposed to be light hearted.

I'm not aware of anyone who's given as much to the Bio world as I have over the last seven years.

Julianf has been in my shed where I shew him how to form a cone, albeit a small one but the principle is the same irrespective of scale.

[julianf]

I don't remember that.  I'm not saying it did not happen, just that i don't remember it.

I would have thought, however, that it would be obvious: If i knew how to do it, i wouldn't be asking.

[therecklessengineer]

The reply was supposed to be light hearted.

I understand now. I'm not sure about anyone else, but I didn't interpret it that way.

Please don't forget that each thread provides information for others as well as OP. I'd certainly be interested to know how you make your cones, as I'm sure would others and those that find this thread in the future. As an owner of one I was impressed with the workmanship.

The above is a CAD screen shot.  I used Tony's calculator for a 45 degree cone, and copied the values into my CAD application.  I figured i could then take measurements from that as to how to tessellate them efficiently.

Aha. Yes, for a 45 degree cone it would certainly make sense.