Making Threaded Prop Adapters
Posted: Apr 20th, 2011, 11:42 am
I get asked a lot about the prop adapters I use with the threaded Robbe props that I run. The adapters I use are custom machined on a small hobby lathe to the specs shown below.
If you do not have access to a lathe, Tower Hobbies sells a coupler seen HERE that can be made into the same type of adapter using drill press and vise.
You may be able to do this with a hand drill and vise but it's not something I would recommend for safety sake. Plus even though the coupler is all ready pre-drilled you probably wouldn't be able to drill the coupler straight either. If the prop adapter is not straight you will get all kinds of vibration as the prop spins.
Using a drill press and a vise (with a v-block to keep the coupler vertical) I start buy drilling out one side using a 1/8" drill bit (or what ever size fits your motors shaft)
Next the coupler is flipped over and the other side is drilled and then tapped to fit a 4mm threaded rod. (or what ever size your prop is) if you can't find threaded rod, you can just cut the head off a 4mm bolt.
The threaded rod is then screwed into the hole you just tapped and is held in place with the one or two of the setscrews.
After that, screw on a 4mm nut, then your prop, then lock the nut back against the prop. (this will keep it from spinning of when you go in reverse)
You can then slide the adapter onto you motor/pump and lock it on with the other set screw.
(See pictures for reference.) (Note - The prop shown in this picture is not the normal Robbe that I run.)
-Steve
If you do not have access to a lathe, Tower Hobbies sells a coupler seen HERE that can be made into the same type of adapter using drill press and vise.
You may be able to do this with a hand drill and vise but it's not something I would recommend for safety sake. Plus even though the coupler is all ready pre-drilled you probably wouldn't be able to drill the coupler straight either. If the prop adapter is not straight you will get all kinds of vibration as the prop spins.
Using a drill press and a vise (with a v-block to keep the coupler vertical) I start buy drilling out one side using a 1/8" drill bit (or what ever size fits your motors shaft)
Next the coupler is flipped over and the other side is drilled and then tapped to fit a 4mm threaded rod. (or what ever size your prop is) if you can't find threaded rod, you can just cut the head off a 4mm bolt.
The threaded rod is then screwed into the hole you just tapped and is held in place with the one or two of the setscrews.
After that, screw on a 4mm nut, then your prop, then lock the nut back against the prop. (this will keep it from spinning of when you go in reverse)
You can then slide the adapter onto you motor/pump and lock it on with the other set screw.
(See pictures for reference.) (Note - The prop shown in this picture is not the normal Robbe that I run.)
-Steve