Pistons and rings

 The pistons have been machined from cast iron. The inside of the piston has been pocketed with a 4mm end mill.Note the fixture top left which is used to hold pistons for finishing the outside and ring grooves

 This image shows the pistons with ring grooves machined and gudgeon pin holes bored.The rings have also been machined with a slit made by a 0.2 mm saw. The ring in the foreground has been heated to dull red with a 4mm nut in the gap. Only two ring grooves have been cut both for compression ,no oil rings at first. These will be added later if found necessary.

Three pistons ready to be installed . The gudgeon pins are oil hardened silver steel. Teflon buttons on both ends of the pins prevent the pins from scoring the bore