Richard Christian

More of my CNC Ruby scripts. The basic 2.5D form was first machined from the dxf. The Ruby script generated the g-code to put in the radiused sides of the triangle. The tool paths are visualised here in linuxcnc.

General purpose vertical bicycle frame jig. The adapter machined here is for locating the main tube on a penny-farthing.

Machining fork plates for penny-farthing. I turned the large holes on the faceplate on the manual lathe, & CNC milled the tube holes of upper & lower plates together in a fixture I made. One of the large holes is the hole for the steering tube. This hole acts as a reference point for positioning the two plates on the fixture.

Building the rim-pressing machine.

Adapter to hold a 25,4 mm tube. Turned manually from free machining steel, 11SMn37.

Some tools I made during my training as CNC machinist. The first is a press tool to dish steel plates for hub flanges: I turned the dished face on a CNC lathe. The second is a tube holder for a jig, made almost entirely in one operation on a 5-axis mill.

Finished flange for the independent 4-jaw chuck, machined from stock ‘verguetungsstahl’ - hardened and tempered steel.

Machining a new flange for a chuck from stock.

Replacement spindle for the CNC mill. This was an interesting problem: fine dimensional tolerances, two threads, and a precision internal taper. I did this in two sittings, turning the internal taper and the external thread near it last by holding the work in a split bushing. Better would perhaps have been to turn a bushing with a fine slide fit for one of the bearing surfaces and threading to hold the work with the other thread. Material is unhardened tool steel, 42CroMo4. 

Prototype hub for a penny-farthing or unicycle. This is the output of a long process of refinement of the manufacture process. The square tapers for the cranks are rough-turned, brazed into the tube, and finish turned with reference to the tube. The flats are then CNC milled, with a nice jig I devised for the purpose. The flanges are silver soldered, and a final cut is taken between points across the bearing surfaces. I’ll post pictures of the whole process soon.