Fly cutter.
Fly cutters are useful tools for surfacing large areas of metal. The one shown above was made from a piece of 1.1/4" hexagon steel bar for the head and a piece of 3/4" round steel bar silver soldered together.
A piece of the hexagon bar was drilled out, on the lathe, 12 mm diameter for a depth of 12 mm. This was cut off at an angle of 30 degrees using the bandsaw. The surface of the 30 degree face was clamped level in the mill vice and then trued up using a 12 mm milling cutter. Next, along the midline of the face a slot was cut to accept a 1/4" HSS tool. Two holes were drilled and tapped M4 for the clamping screws along one face of the hexagon, as shown above. A 80 mm length of 3/4" bar was prepared by turning the end down to be a sliding fit in the drilled hole in the hexagon piece. This turned down section was 12 mm long and the shoulder should bottom against the hexagon piece. The other end of the bar was centre drilled. The two parts were then cleaned with kerosene and the mating surfaces fluxed with Easiflow flux. The parts were then silver soldered together and after cooling a little the head plunged into old engine oil. This gives a black colour to the parts as can be seen on the head of the flycutter.
The hexagon part was then clamped in the three jaw chuck and the other end mated with a tailstock centre. The MT2 taper was then cut. As a final operation the centre was removed and the shank drilled and tapped M10 for the draw bar.
The HSS tool was ground like a left hand lathe tool. When using the fly cutter it is very important to use a sharp, fairly pointed cutter, to run at slow speed and to wear suitable eye protection because the swarf flies off with some velocity in all directions. This tool will sweep a circle 80 mm diameter with the tool protruding 20 mm from the head.
A piece of the hexagon bar was drilled out, on the lathe, 12 mm diameter for a depth of 12 mm. This was cut off at an angle of 30 degrees using the bandsaw. The surface of the 30 degree face was clamped level in the mill vice and then trued up using a 12 mm milling cutter. Next, along the midline of the face a slot was cut to accept a 1/4" HSS tool. Two holes were drilled and tapped M4 for the clamping screws along one face of the hexagon, as shown above. A 80 mm length of 3/4" bar was prepared by turning the end down to be a sliding fit in the drilled hole in the hexagon piece. This turned down section was 12 mm long and the shoulder should bottom against the hexagon piece. The other end of the bar was centre drilled. The two parts were then cleaned with kerosene and the mating surfaces fluxed with Easiflow flux. The parts were then silver soldered together and after cooling a little the head plunged into old engine oil. This gives a black colour to the parts as can be seen on the head of the flycutter.
The hexagon part was then clamped in the three jaw chuck and the other end mated with a tailstock centre. The MT2 taper was then cut. As a final operation the centre was removed and the shank drilled and tapped M10 for the draw bar.
The HSS tool was ground like a left hand lathe tool. When using the fly cutter it is very important to use a sharp, fairly pointed cutter, to run at slow speed and to wear suitable eye protection because the swarf flies off with some velocity in all directions. This tool will sweep a circle 80 mm diameter with the tool protruding 20 mm from the head.