DragBikeMike
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SuzukiSavage.com Rocks!
Posts: 4470
Honolulu
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Regarding the gear machining, there is only one critical step. That would be cutting the fit on the larger gear, the one that was originally installed on the oil pump. It has a small hole in the center and spokes that connect the center hub to the tire. That fit will be your reference and must be machined before the spokes are severed. You need to use carbide tool bits and adequate cutting oil. It’s a very small cut, just enough to establish a true circular fit that is concentric to the gear tooth pitch diameter.
I achieve that by using a spud. I machine an aluminum spud using my three-jaw chuck. That spud has a machined diameter just about .0005” smaller than the center hole in the gear. I also drill and tap the center of the spud for a pinch bolt. Once I have machined the OD of the spud and drill & tap the hole, I do not take the spud out of the chuck. That way, the fit on the spud will be running exactly true. Then I place the gear onto the spud and clamp it to the spud with the pinch bolt and washers. Since the spud runs true the gear will run true.
With the gear running true, I take very light cuts with a small carbide boring bit (must be a boring bit). Remove just enough material to clean out the radius and establish a circular fit for the new aluminum hub. Make sure to accurately measure the diameter of your new machined-fit before you cut through any spokes.
When you cut through the spokes to remove the center hub of the gear, it will go out-of-round. Not a problem. The new hub you make will have an OD the same size as the fit bore. When you install the new hub in the gear tire it will make the gear round again.
I believe FinnHammer made a special holding clamp so he could keep the gear round for machining operations etc. I’m too lazy to do that, I just use the new hub to make the gear round again. When I cut the spokes, I left about .015” clearance with the shoulder on the new hub. I just use the spokes to provide a place to secure the gear to the hub, they don’t accurately locate anything.
This is a picture of the gear mounted in a four-jaw chuck. The dial indicator is reading on the new fit for the new aluminum hub. I was trying to see if I would be able to clean up a bore in the spokes once I severed the spokes. The aluminum spud is still in the gear. Sorry, I guess I never took a pic of the gear and spud mounted in the three-jaw. Hope you get the idea. The spud gets mounted in the three-jaw and machined to suit the center bore in the gear. Then, without removing the spud from the chuck, the gear gets clamped to the spud. Now the gear is running true. Then the fit is cut. Then the spokes are severed. Once severed, you don’t need to machine a bore in the spokes. You can simply grind them with a die grinder to provide adequate clearance with the new hub.
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