RMC Type'b' Loyal Cycle Project |
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The Connecting Rod. What can I say, not exactly the most glorious piece, but it presented a challenge since I don't have a ball turner for my lathe. I really like the look of the conrod as it's drawn though. What to do.....? I had thought about a 3 piece conrod, but it was simpler to make it 2 pieces because I wanted brass for the end that connected to the flywheel. |
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Now is time to turn down the shank on my version of the conrod. It differs from the one in the plans, so we will see how this works out. I reduced the shank to .198" and threaded it 10-32 |
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Brass square stock was choosen to make the conrod 'big end'. Basically it is just turned round to the required outside diameter plus .010" |
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The end is next rough profiled to give me plenty of meat for the 'ball' that will be the big end. I have started to turn the stem to size also. |
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After I made some roughing cuts to a ball shape I decided to make a ball turning tool just for the fun of it. What the heck, it never hurts to have another useful tool! |
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The results of the ball turning tool were nice. Like any tool it takes a little getting used to. Here is the ball turned to size with the stem turned to its major OD. I mounted them in to the mill vise to cross drill the crank pin hole. To find the center of the ball, mount the center drill in the chuck and bring it down to about 002" above the ball, then use the fine feed to bring it down .001" at a time and run the bal under the bit. The highest diameter spot (center of the ball) will recieve a mark from the bit. Congrats, you found center. |
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Since the ball has been center drilled, drill with the next size smaller bit than the bushing and ream to fit the bushing. |
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The bushing is pressed in to place and then the oiling hole is drilled through the bushing so the crank pin can get lubed. |
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A little more profiling, cleaned up, and tapped 10-32. Then I checked overall length and brought it to spec so that the threads were just long enough to give me the proper conrod length minus about a quarter turn. Everything was cleaned and then I used loctite bearing retainer (green) and assembled the two pieces. The final quarter turn adds a little 'friction fit' and helps the loctite do its job. Now we will have to see if it stands up to the abuse. |