Soffietta construction

circle shear

The start of a soffietta, a square of brass sheet. This is cut using a circle shear to form the round blank to be spun into the cone of a soffietta.

blank after shearing

The cut blank. The waste piece from the outside will go into my scrap brass collection and will eventually make it's way to the scrap metal dealer.

1st stage spinning

The blank is clamped between the chuck which the metal is laid down onto, and the follower. It is then spun part way as shown. The spinning process work hardens the brass so at the point shown the cone is removed and annealed before further spinning.

2nd stage spinning

After annealing the cone is completed by laying the brass fully onto the chuck.

boring boss hole

The tip of the soffietta cone will be formed by a brass insert so the small end of the cone is machined to accept it. The fixture shown allows the cone to be quickly and accurately held for this operation.

cone boss

The brass insert which will form the tip of the cone. This shows the thread which will be used to hold the cone onto the soffietta tube.

soldering cone

Soldering the insert to the cone. The join has been fluxed inside and out and a ring of silver solder placed inside around the insert at the base of the cone. The join is brought up to the melting point of the solder at which point it will melt and flow through the join forming a fillet inside and out.

machining cone

After pickling in a mild acid solution to remove flux residue the cone is mounted on a mandrel to machine the tip of the cone. The neat fillet formed by the solder is clearly visible at the join.

finished cone

A virtually completed soffietta cone. After machining any final blending is done with a fine file. The last step is to give the cone a uniform finish with a woven abrasive pad.

completed soffietta

A selection of completed soffietta.

Top is for solitary use by the blower themselves.

Middle is a swan neck which balances to hang vertically and is used by an assistant.

Bottom is straight and used end on to the blown piece by an assistant.

Soffietta with added grip

A soffietta with knurled aluminium grip.