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44 Tooth Stunt Cog for direct drive (ebay 7105073365)
Hello, rbt!
This cog is threaded 1 3/8-24 and was used to drive a generator at 50-100 W as well as to hop the front fork. I made two. The lot of two starts at $24.95, which is what I paid for one spider and cog with nuts. Buy it now for $49.90. Anyway, the relevance of this post is mostly in the description of the manufacturing method, not completely discolsed in the auction listing. I bought a steel spider with nuts and a chrome plated 44 tooth cog already installed. It had a 110 mm bolt circle. My intent was to adjust the gear ratio to match the generator output to my average forward speed, providing constant power on level ground. This I did. The spider had a 7/8 inch hole in the middle, and a 3/4 inch insert, which came out easily. I used a Unibit to drill the spider to 1, 1 1/8, and 1 1/4 inches, which was farly close to the required size for tapping 1 3/4 - 24. This size I can't remember. I went ahead with the tapping using a center point in the drill press to hold the tap over the hole, restraining the cog with a screw in a pattern of jigging holes in the drill press table. That pattern was drilled on 1 x 1 inch centers and tapped M6x1 long ago, for use with a cross vise I still use. I screwed a chrome plated hub into the spider and added a bottom bracket lock ring, a black one, with the finish sanded down. I'd removed the adjacent spider paint. I added a spacer of thin derailer cable wire (a single strand) when I soldered, but the first time through I brazed it in an oven of fire bricks, and set off my apartment ion detector. (Smoke alarm) I forget actually how I aligned the threads or whether I soldered and brazed with the rear hub in place. I really do. I painted one spider and since the other was less damaged by soldering, left it as it was. That's about all. Yours, Doug Goncz ( ftp://users.aol.com/DGoncz/incoming ) Student member SAE for one year. I love: Dona, Jeff, Kim, Mom, Neelix, Tasha, and Teri, alphabetically. I drive: A double-step Thunderbolt with 657% range. |
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#2
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Doug Goncz wrote: Hello, rbt! This cog is threaded 1 3/8-24 and was used to drive a generator at 50-100 W as well as to hop the front fork. I made two. The lot of two starts at $24.95, which is what I paid for one spider and cog with nuts. Buy it now for $49.90. You stock low cost stunt cogs? Try saying that fast. Cam "sorry" Barr |
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Doug Goncz wrote: Hello, rbt! This cog is threaded 1 3/8-24 and was used to drive a generator at 50-100 W as well as to hop the front fork. I made two. The lot of two starts at $24.95, which is what I paid for one spider and cog with nuts. Buy it now for $49.90. You stock low cost stunt cogs? Try saying that fast. Cam "sorry" Barr |
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