WORKSHOP TIP Boring Eccentrics

摘要

I am making a 1 inch Minnie traction engine and have arrived at the machining of the eccentric straps. The castings provided have a rough hole in the centre. In the past, I have made eccentrics for steam engines using solid castings. I machined them to approximate size, drilled holes for the bolts to hold the halves together and then cut the body in halves across the centre using a thin slitting saw. The halves were bolted together and the centre of the work established along the sawcut. The centre was clearly identified and initial drilling and work with the boring bar soon established the hole for the eccentric - a comparatively easy set of operations.