Tuesday, April 7, 2015

Lost And Foundry

The lathe project requires a three step, cone pulley with a one inch bore. They run about fifty bucks. No way am I going to shell out half a hun for a lousy pulley. I decided to make my own. I made a pattern from plywood, rammed it up in the flask and lit the furnace. I knew, right away, that my chances for a good part were slim so I allowed myself one failure. It is a large casting and I needed to melt a full crucible of aluminum. The lid on my furnace fell apart when I was making the water pump for the bike. I thought I could just use a piece of steel as a lid. Not so. I need a lid that holds the heat in in order to get a full melt. I tried some bricks and It seemed to work. I had a full load of alloy, ready to pour, or so I thought. As I poured it, I realized that it wasn't going to go well. It wasn't fluid enough. The casting was useless. So, I initiated Plan B. Since this is a low stress deal, I decided to make a wooden pulley. I planed a piece of maple to 5/8 inch and cut out four circles, 6, 5, 4, and 3 inches. I glued them together and, after it dried, I bored the center out to 1 3/8. I had a piece of 1 3/8 DOM tubing that I bored to 1 inch ID on the metal lathe. I pressed it into the wooden pulley. Using the tailstock spindle as an arbor, I chucked it and the pulley into the lathe. Using both the crossfeed and the wood lathe chisels, I whittled the blank pulley into a pretty good looking finished part. I then drilled through the wood and the steel core and tapped it for a set screw to keep the two parts together and to secure it to the headstock spindle. So far, I have a total expenditure of 50 bucks in the project. I think I will be able to come in at hundred bucks total cost, certainly no more than 150. I have several good motors to choose from as well as two or three of the smaller cone pulleys. Tomorrow, I'll pick up a sheet of plywood for the lathe bed

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