[NaturalFork]

So I was thinking. Inner diameter of your blowpipe x pi equals the circumference .. then if you did the same thing for the diameter (roughly) of the shaft you ar attaching to .. couldn't you come up with a very easy template for uniform hassle free cone making?

Something like the following? Of course you would add a little extra length for the overhang where you would tape or glue the cone.

Note that this illustration was done in 30 seconds in paint and does not represent any actual measurements ... just gives an idea. I will actually work out the math and get an image together in GIMP and make some cones to see how they come out.

 

[Michel]

Hi,

Good idea, but the top and the bottom have to bee circleparts.

Caveman think about this, in a little other way, a few years ago

Look here: http://www.polar-electric.com/Blowgun/Darts/MakeDart.html

Michel

 

[NaturalFork]

You are absolutely right. When I was originally thinking about this I thought they would need a curve. Does anybody know how to calculate the curvature needed?

 

[Michel]

Hi,

you need the periphery of circle of your BG-caliber = 2r x Pi = d x Pi = U1

for example you shoot a .625 0,625 inch x 3,1416 = 1,964 inch

16mm 16mm x 3,1416 = 50,27mm

1/4 circle will get a nice cone, so you need 1,964 + a little for the glue = 2,1inch

50,27mm + a little for the glue = 53mm

so a the periphery of the full circle, U2 = 4 x U1

4 x 2,1inch = 8,4inch

4x 53mm = 212mm

the radius of this circle r2 = U2 : 2 : Pi r2 = 8,4 inch : 2 :3,1416 = 1,34inch

r2 = 212mm : 2 : 3,1416 = 33,7mm

if you want a slimmer cone, you can take U2 = 6 x U1, than you need a segmet of the circle of 60°

Michel

 

[neondog]

I use an inch and three quarter blanks when rolling cones but nearly half an inch is trimmed off so 1.34" seems about right.

 

[Pelletor]

Nice technique Neondog and great looking cone!