Homebuilt ROVs Forum

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

Thanks for the help Steve!

Some treadlock on those set screws would be a good idea.

The little buggers like to come out!

Not good 300m down with no props

GEEB :mrgreen:

Hi All,
If you are using the Robbe propellers with the 4mm threaded holes and a motor with a 1/8" shaft, like the Mayfair bilge pump motors, you can use the Grand Wing DS003 3mm to 4mm propeller adapter if you can find them for sale anymore. One end is a 3mm hole with two set screws on either side and the other end has a shaft with 4mm threads. There is about 1/2" of unthreaded shaft ahead of the threaded part, but that can be easily cut off. I believe that adapter is made out of SS. I bought the last two at BP Hobbies and they do not expect to get anymore in unfortunately.
Regards,
TCIII Former Submariner

Steve,

Would you be willing to make some more of those threaded prop adapters? I would pay you for them. Name your price.

Thanks!

Sorry unfortunately I just don't have the time to make any right now.

-Steve

sthone wrote: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.

The prop shown in this picture is not the normal Robbe that I run.)[/color]

-Steve

Hey sthone,

What motor are you showing in your pics? Thanks.

Randy

Those are 750 GPH Mayfair Bilge Pump Replacement Motor Cartridges made by Johnson Pump. They use to be a cheap way to make thrusters but the prices have gone up in recent years.

-Steve

sthone wrote:Sorry unfortunately I just don't have the time to make any right now.

-Steve

I could use a little extra income and could make prop adapters to your drawing(s). I assume stainless steel? What would one be worth do you think? Could there be a market for these?

Randy