ATOMATIC 5
5cc ITALIAN BEAUTY
Part ten - cylinder liners - by Ramon Wilson
ATOMATIC 5
5cc ITALIAN BEAUTY
Part ten - cylinder liners - by Ramon Wilson
Liners came out of a piece of very free cutting leaded steel. The bores were finished before the ODs to keep the wall thickness as much as possible to prevent distortion. Once done - to measurement using tele gauges (no plug gauge) the ODs were quickly roughed from each end to 1.0mm over size. One end (which will be the lower) was faced at the same time as doing the bores. The pic is of roughing the OD - not facing the other, top, end.
Very different to the usual 'tommy bar in a hole' practice these require a shaped blade as the lever. The profile was copied onto a piece of card and cut out then transferred to the material - steel for the bead version and a brass one for a bit of bling. The levers were silver soldered into bosses first.
The inlet 'regulators' were turned from brass and steel respectively - these had an 8mm slot run up the back and were expanded slightly using a tapered mandrel (dot punch) in the tailstock. This has given a nice tight fit but allowing smooth rotary motion.
The tank filler parts were also completed.
In the past the rotors have been turned on the end of a block of Tufnol, the profile and any lightening cavities milled in then the rotor itself parted off. I tried something different this time, in parting off two discs a mil thicker than the thickness required. These were then faced and bored to a running fit on the bearing before reversing and facing to finished thickness.
A stub of ali had a stepped washer turned and parted off before turning a register for the rotor and drilling and tapping. With the chuck on the rotary table the inlet cavity was quickly milled. First off was the drive pin location - the rotor reference point.
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