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	FastElectricRC.com: Assembling Radio Control Boat Flex Shafts
	Assembling your own flex shafts is an easy and cost effective alternative to higher priced soldered ones. The biggest advantage to "doing it yourself" is cost, a soldered flex shaft is about 18.00 and that doesn't include shipping. Using my "glued" method the flex shaft will cost roughly 5.00. Another advantage is you can reuse your stub shafts when a cable gets twisted or shows signs of rust/excessive wear. You could also do this with soldered shafts but the process isn't nearly as easy and if you're not comfortable with high temp soldering it's best left to a person that is. The method I use may seem a bit unconventional but I have never had a flex shaft fail because of a poorly made joint and you need no special skills to do the job correctly. If you follow the steps outlined you'll be rewarded with a strong flex shaft in less than a half hour (minus glue set time) and the money you save can be put into spares! What you need: Left lay .130 flex cable (left lay is standard, Hughey, Octura etc.) 3/16 stub shaft & Drive Dog (Hughey or Octura, depends on application or preference) Permatex High Strength Sleeve Retainer (Napa Auto Parts) Start the assembly process by cutting off a piece of flex shaft from the bulk flex purchased. To get the approximate length just slide the cable through the strut mounted on your boat into the coupler on the motor. Mark the flex cable right where it exits the strut with a marker, this will be a bit longer than needed but we'll fine trim it later. Note: The best method for cutting flex shaft is with a cut off wheel on a Dremel tool. What I recommend doing is rotating the cable with your fingers in the direction of the wind while cutting rather than cutting straight through it. This reduces your chances of having the cable "unwind" while cutting. A light pressure against the cut off wheel is all that's needed, don't try cutting it too quickly. The picture bellow shows the cable cut part way through. BTW: Don't forget to wear your safety glasses. When you're done cutting you should have a nice smooth finished edge like this. Now you need to prepare the cable and stub shaft assembly. If you use a Hughey stub you'll need to install the drive dog onto the shaft. First thing to do is clean any metal burrs from around the hole in the shaft, do this with a small file. A light touch up is all that's needed to allow the drive dog to slide over the hole in the shaft. Once you have the hole in the drive dog and shaft lined up you can either tap the pin in with a small hammer or use a pair of pliers to squeeze the pin in. After the pin is installed file off any excess pin flush with the drive dog. On an Octura stub shaft the drive dog is held on by a set screw, in that case you would simply grind a small flat on the shaft in the appropriate location. Now prepare the stub shaft and flex cable by sanding about a half inch of the cable end and the inside of the stub shaft with 220 grit (or less) sandpaper. After sanding you'll want to clean the cable and stub with motor spray. I use a product called CRC Lecra-Motive, this stuff works great and is about half the cost of the hobby brands, it's available from the auto parts store. Notice the dirt/oil removed from the shaft after sanding. I recommend cleaning the shaft where you sanded at least twice. Now that the two parts are clean and dry it's time to join them. Take the sleeve retainer and put a couple drops on the flex shaft and set it on a paper towel. While that sets a moment put a couple drops of the sleeve retainer into the stub shaft hole, take a pin and work the two drops into the hole of the stub shaft. Now take the flex cable and slide it into the stub shaft, rotate the cable as you're pushing it in to make sure it fully seats. Any extra sleeve retainer will be forced out and simply wipe off the excess with the paper towel. Once the cable/stub are joined set them aside undisturbed for 24 hours. Now that the flex and stub are joined and set you need to cut the cable to the correct length. Slide the flex assembly into your boat making sure the cable is bottomed out in the motor coupler. Take a measurement from the end of the strut to the front of the drive dog. In the picture you can see the gap is about 3/16". Remove the cable and make a mark on the cable at the measurement you just took and cut the cable on that mark. Remember: measure twice cut once! That's it, the cable can be used as is but I take mine a few steps further. If you use an Octura Flex Hex coupler the following step isn't absolutely necessary but if you use a set screw type couple I highly recommend doing it. What I do is tin the end of the cable with solder, this makes the cable end that goes in the coupler solid and keeps it from unwinding. First sand and clean the end of the cable like you did before for the stub end. Next lightly coat the clean end with soldering flux. About a half inch from the end of the cable is plenty. Heat the end of the cable with a soldering iron, at least a 40 watt iron should be used. You will see the flux bubble and melt into the cable, this takes 15 to 30 seconds. Now take your solder (I use 4% silver solder) and apply it to the cable while the iron is still in contact with it. You want to coat the cable but you don't want the solder to build up on it so once you see that the solder has coated the cable remove the iron and tap the cable on your solder board to remove the excess solder while its still hot. When you're finished you should still be able to see the cable outer wrap of wire. If you happen to get too much solder on the cable you can just sand off the excess. The next steps are more of a finishing touch than anything else. I polish my flex shafts, I don't know if it enhances performance but I know it doesn't hurt it and since it only takes a few minutes I make it part of the routine. Start by putting the flex shaft in a drill at the stub end. Start with a piece of 220 grit sandpaper, while the drill is running run the sandpaper up and down the flex shaft for about 30 seconds. Repeat this process with 320, 400 and finally 600 grit sandpapers. When you're done sanding take some metal polish and apply a small amount to a paper towel. I use Simichrome but any paste type metal polish works fine. Now lightly hold the cable in the paper towel and start the drill, work it back and forth like you did the sandpaper. I do this for a minute or two, you know when it's finished when the paper towel is nice and black. Now just wipe it down with a clean cloth, the end result is something like this. That's all there is too it! Like I mentioned I have NEVER had a shaft fail me using this method and if you try it I'm sure you won't either. If you find you need to replace a cable simply heat the glue joint with a propane torch or soldering iron and pull the cable out. Clean the inside of the stub with a bit of sandpaper and it's ready again. Please let me know if you have any questions that I may not have covered, I'm happy to help.

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