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A Person
I had some free time this weekend and decided to try an idea I had. I started by modeling it up and making a plan.
From here I made a plan for what I wanted the rough stock to look like. This whole idea revolved (pun intended) have a close fitting shaft slid into a boring bar holder.
Here you can also see the drawing I made as a reference. I ended up changing some things on the fly. The stock I was using is some 7075 timing pulley stock that I picked up at the scrap yard. This gave me the perfect indexing marks (although not actually perfect). Because the stock was 33 teeth, I did 3 fins.
Endmill in a collet, thick ruler as the indexing finger, and (not pictured here) a screw and large washer on the back to prevent it from sliding forward while the clamping nuts are loosened.
After a couple more hours of machining, I have the "corners" to a point they and be pulled off with pliers. This leaves me with the 3 fins sticking out of a roughly square block.
After more passes I get to this point. It is kind of a low poly version of the final product. Here you can see that my fins are not perfectly on center. I need to figure out a better method of determining the cut height and centerline.
Next up was many passes with very small incremental moves. I removed the ruler and would manually rotate it a small amount and then take a pass. This was the first section I did and you can see that I cut into the fin itself some. I was eyeballing the limits and that is hard to do with all of the chips and oil on everything. At this point the milling portion was done and All that was left was to clean up the ends, turn a shoulder for the tube, drill the center out, and part it off.
The OD was originally intended to match a standard body tube, however, I found a short piece of 3/4" OD aluminum tubing and decided to make the body tube out of that. As a result the fincan OD is a little larger than the body tube. I also made a quick nosecone to complete the look and then got to the fun part.
This was done with needle files for the rough work and then these sanding needles for the finishing. Some of the lines from the endmill passes never did fully clean up. I am pretty pleased with how it came out for a first try. Eventually I would like to make a proper one for a 29mm motor and maybe even a flyable 18mm version.
Maybe I will polish the tube in the future but for now it will live on my desk at work.
From here I made a plan for what I wanted the rough stock to look like. This whole idea revolved (pun intended) have a close fitting shaft slid into a boring bar holder.
Here you can also see the drawing I made as a reference. I ended up changing some things on the fly. The stock I was using is some 7075 timing pulley stock that I picked up at the scrap yard. This gave me the perfect indexing marks (although not actually perfect). Because the stock was 33 teeth, I did 3 fins.
Endmill in a collet, thick ruler as the indexing finger, and (not pictured here) a screw and large washer on the back to prevent it from sliding forward while the clamping nuts are loosened.
After a couple more hours of machining, I have the "corners" to a point they and be pulled off with pliers. This leaves me with the 3 fins sticking out of a roughly square block.
After more passes I get to this point. It is kind of a low poly version of the final product. Here you can see that my fins are not perfectly on center. I need to figure out a better method of determining the cut height and centerline.
Next up was many passes with very small incremental moves. I removed the ruler and would manually rotate it a small amount and then take a pass. This was the first section I did and you can see that I cut into the fin itself some. I was eyeballing the limits and that is hard to do with all of the chips and oil on everything. At this point the milling portion was done and All that was left was to clean up the ends, turn a shoulder for the tube, drill the center out, and part it off.
The OD was originally intended to match a standard body tube, however, I found a short piece of 3/4" OD aluminum tubing and decided to make the body tube out of that. As a result the fincan OD is a little larger than the body tube. I also made a quick nosecone to complete the look and then got to the fun part.
This was done with needle files for the rough work and then these sanding needles for the finishing. Some of the lines from the endmill passes never did fully clean up. I am pretty pleased with how it came out for a first try. Eventually I would like to make a proper one for a 29mm motor and maybe even a flyable 18mm version.
Maybe I will polish the tube in the future but for now it will live on my desk at work.
