I am almost done. All that remains is to construct the valve actuator (tapper) and to finish work on the wooden base.
Today I finished up machining the piston. This was by far the most complicated and nerve wracking part to make. Lots of tricky operations and lots of opportunity for bozo moves! Any one of them would have set me back to starting with a new piece of round stock. A few times I got stumped for a bit while I figured out how to proceed. Fortunately I think I have succeeded on the first try.
I am almost done. All that remains is to construct the valve actuator (tapper) and to finish work on the wooden base.
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Last Friday, I took sent DXF files of the cam and the crank arm to a local firm that has a water-jet cutter. Today I got them back and they look fantastic. It cost me about $50 to do, but it saved me a lot of time I otherwise would have had to spend to make the parts by hand. The holes needed a bit of reaming and one of them needed to be threaded, but other than that, there was little I had to do to them.
Today I finished up work on the main bearing frame. I also cut the key-ways on the crank shaft for the 30 tooth gear and the crank handle. Then I pressed the shaft onto the flywheel. I had to make a shim to allow the flywheel to fit to the 5/8-inch diameter shaft.
After that was done, I test assembled the components on a scrap piece of wood just to see what she would look like. See picture below. Today I worked on building the crankshaft frame. This took a full day to make, but I managed to do it without any bozo moves. With this done, all that remains is to:
For these last two items I decided to get them cut with a water-jet at a local metal supply place. Hopefully this is not too expensive. They could not give me an exact price at the time. Today I received my centering indicator in the mail, so naturally I wanted to try it out. Today I worked on the exhaust valve. This involved many operations that I have never done before, but it seemed to work out in the end.
Today, I came home to find a large parcel waiting on my porch. It was some new tools for the shop. A set of key-way broaches and a set of v-blocks. As it turned out, I needed both of them tonight. A few months ago, I ordered the two timing gears from Amazon. Unfortunately they did not carry the 30 tooth gear with a 5/8-inch bore, or key-way. Since I was using a 5/8-inch diameter crank shaft, I had to bore it out , and then cut a 1/8-inch key-way. Both operations went surprisingly smoothly, though I did have a bit of trouble with a dull 5/8-inch drill bit, which I promptly tossed away. Below is some photos of the gear being modified. Another job I needed to do, was to hone out the cylinder sleeve. I picked up hone used for brake cylinders at Princess Auto for about $6.00. The v-block came in handy to hole the cylinder sleeve in the vise while I honed it.
I ordered a Coaxial Centering Indicator for setting up the exhaust valve body to modify the original valve seat and bonnet. As this has not arrived yet, I did some work on the valve actuator instead. After locating a suitable spring (from Home Depot) I proceeded int machining the valve guide on the lathe. Initially I thought I could use an existing plumbing par to build this, but in the end I had to resort to using 1/2-inch brass round stock. This wasn't too bad of a part to make, though the little piece that sits at the end of the spring was a bit of a challenge because it was so small.
There are some minor work to complete on the combustion chamber which I will work on next. Then (if my centering indicator has not yet arrived) I will start working on the Main Bearing Frame. TV back in the 1970s wasn’t like TV today. We only got two (English) channels in those days and more often than not, shows I liked to watch would get preempted by “A Special Presentation”. It was on one of these days, when I was about 10 or 11 that I found myself with nothing interesting to do. I decided to pull some books off of my dad's bookshelf at random and started reading. My dad had a set of three electronics books from Howard W. Sams. These were "99 Electronic Projects", "5 Minute Electronic Projects" and "How to Build Electronic Projects". As luck would have it, it was these I pulled that day. I am not sure why my dad bought these books, because as far as I know, he never got into electronics. After an afternoon's read, I managed to memorize all the schematic symbols and after that, I was hooked. I could not wait to get cracking on building my first electronic project. These three books kindled my interest in electronics, a hobby I still enjoy very much.
The first 1920s radio I ever picked up was one made by a company called Workrite, out of Cleveland, Ohio. Search as I might I have never come up with anything on this particular model. Over the years I came across references to Workrite radio kits and suspected that this one could be one of those. Yesterday I happened upon a listing on eBay for another Workrite radio. It had a similar layout to mine, but it looked smaller and the electronics were not laid-out quite the same as mine. However, the seller also posted photos of the plans used to build it, and the component layout shown in the plans was identical to mine. Finally I had the proof that my radio was indeed built from a kit. According to the drawing, this design was made in April 1924, so now I can date this radio too.
I contacted the seller to see if he would scan or photograph the plans in detail and he promises me that he will. Can't wait to get those! Today I think I hit the mother load in terms of old radio documentation. The site is called www.americanradiohistory.com, and they have all sorts of early radio magazines in PDF form posted. Everything from "Electrical Experimenter" to "Radio Craft" and many others. If you are an antique radio junkie like myself, then check it out.
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AuthorCharles Baetsen holds a Bachelor and a Master's degree in Engineering Physics from McMaster University in Hamilton, Canada. Archives
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