That’s my coupler history (from left to right)
So which one would you recommend? I had a discussion with a friend who is a mechanical engineer with experience in that field. He recommended a clamp style coupler, not one with set screws, best would be one with 2 screws on each side for max strength, but this increases the length. Also he recommended to use two bearings on the shaft so this would match with Hiorts brothers drawing above. My friend also suggested to invest in a machined part (with a lathe) because with 3000 rpms, the shaft needs to be perfectly aligned to run true.
Straight couplers are pretty much useless. No shaft is perfectly straight. This would cause binding.
My experience with clamping only the shafts is that I had to dissamble my whole pod at the beach (like at least 3 times) because it always got loose (shaft was not clamped anymore because the torque is way too high). Even with lock tide and a high screw tightening torque it wasn’t possible.
A combination of both is in my opinion the best option. I also have an additional bearing so it’s a need for having a flexible coupling.
I recommend the jaw coupling with two threads for set screws and a shaft with a flat spot.
The Jaw Coupler failed today as well:
@Hiorth: How much torque does your setup has, roughly?
The next one I will test is this one (for max. 10Nm):
Apx 10-12nm you need a spider that can handle sufficient torque.
Can you provide a link, please?
25 x 98 shore
max torque from motor with gearbox is probably 8-10nm.
Thanks Hiorth! I didn’t expect that the coupling will be such a problem. Good ride!
Just to confirm this a second time:
As you have stated before those spiral couplings can‘t handle the torque. I used it until my elastic star coupling arrives. It failed after a few hours of testing in my jet drive with max 3.6Nm. It took only a small leaf through the impeller to finally break it.
I looked at the maedler site again this afternoon, but I will try the jaw coupling I ordered first.
Did you already test this one?
Nope. But take care that the jaw coupling will only work in forward direction if you don’t secure the shaft axial.