Hi there,
I'm making a gear to go on the end of an engine that I am manufacturing. Before we start, no I cannot use a standard gear, or go and buy one. I need to shrink fit a gear onto a shaft. This gear drives a cam chain system for the engine. What is the best way to positively lock this gear considering that the gear and the shaft will have been case hardened. I originally had a key way in the shaft but I think the stress raisers will be too large. My first thoughts were once the gear has been shrunk into place, drill a small hole axially in the interface between the gear and the shaft and to press in a small pin to stop the two from twisting. My concerns with this are 1) If I drill say a 3mm hole for this pin and the case hardening is less than 1mm deep, will this discontinuity in the hardened layer screw with everything? 2) Drilling through hardened steel is a horrible experience, especially when the shaft and gear you are making are quoted at $1500.
Background info: I am making a V-Twin engine from two single cylinder engines. The gear drives a layshaft which drives the camchain on one cylinder as its direction needs reversing. The shaft I spoke of is not so much a shaft, it is more another gear. This gear has a shaft from one side for this other gear to fit onto. This mega gear then slides on a spline on the crankshaft.
I'm making a gear to go on the end of an engine that I am manufacturing. Before we start, no I cannot use a standard gear, or go and buy one. I need to shrink fit a gear onto a shaft. This gear drives a cam chain system for the engine. What is the best way to positively lock this gear considering that the gear and the shaft will have been case hardened. I originally had a key way in the shaft but I think the stress raisers will be too large. My first thoughts were once the gear has been shrunk into place, drill a small hole axially in the interface between the gear and the shaft and to press in a small pin to stop the two from twisting. My concerns with this are 1) If I drill say a 3mm hole for this pin and the case hardening is less than 1mm deep, will this discontinuity in the hardened layer screw with everything? 2) Drilling through hardened steel is a horrible experience, especially when the shaft and gear you are making are quoted at $1500.
Background info: I am making a V-Twin engine from two single cylinder engines. The gear drives a layshaft which drives the camchain on one cylinder as its direction needs reversing. The shaft I spoke of is not so much a shaft, it is more another gear. This gear has a shaft from one side for this other gear to fit onto. This mega gear then slides on a spline on the crankshaft.
