I ordered a couple similar but have not used them because they look a lot like some that have broken under the high torque pressures in other builds. See Flo’s post on April 25 above. But It might be that the one you are referring to is stronger.
Any idea where to buy high torque flex coupler in US?
Here are two U.S. sources I have bought couplings from:
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@sunrise305 I am having hard time to locate one with high tourque. I couldnt find any in macmaster with more than 4 nm max tourque
I ordered THIS COUPLING from SDP/SI but have not used it yet so cannot confirm its suitability. But it is rated 8 nm.
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What do you guys think about this one?
it is up to 12.5 nm torque
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I have a couple of similar multi-piece couplers. It’s not clear to me what will keep the parts together when there is nothing else holding the prop shaft in place.
I guess I found a giid coupler. Just confirmed the 12.5 continuous torque and 25 nm max with the US seller:
I ordered one to start testing it
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here is one way to do it.
2x deep grove bearings.
been running a motor with this configuration for half a year. quite a lot of parts but it works 
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Best I can tell the unmodified PacificMeister “SealMount” component will not properly hold a multi-part coupler in place since there is noting to keep the parts in place. Aft of the coupler there are only two seals and one bearing., all of which allow the shaft to slide freely. Under normal operation conditions the forward prop thrust should keep a multi-part coupler in place. But – unless I am missing something – touch reverse and you may find the shaft and prop pulling aft and opening the coupler. There’s nothing to hold the three pieces firmly together. Thus in this build the specified fixed (or at least single piece) coupler is required.
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HI Hiorth! I will change my blue alu coupler from PM for a new one. You’ve used the “jaw spider clamp”, do you think it is a better solution than the “rigid clamp”? This supplier provide both in custom size (and the price is ok) 8 x 10mm Flexible Jaw Spider Shaft Coupling CNC Stepper Motor Coupler Nema 23 34 | eBay
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hi!
i think it definitively is better to change to a more solid type of coupler. Ideally made from steel with a tight tolerance relative to the shaft. I think ideal material would be steel.
we have been using couplers from ruland and they are very good quality and have not failed yet.
also I would recommend using an adhesive like Loctite 648 to mount it.
if you are changing to a "jaw spider clamp" you must have additional support of the prop shaft in axial and radial direction. i would not recommend this if you are using 3d printed parts.
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Hi,
on recommendations of @Hiorth , I made this coupler. It is a copy of Ruland (sorry) but they are hard to find here and very expensive. the propeller shaft is of diameter 10. So, Wait and see.
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it’s not a coupler it’s just a jewelry
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and how long is it? To not have to modify anything in PM’s pieces the coupler must be 25mm long. So you did your copy by ourslef? Or where did you get it?
The coupler is made of steel and weighs 81 gr. L=27mm. (Homemade)
What do you think if the coupler is in aluminum ? This weight will be 25 gr.
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Ok! is it something you would be ready to sell or did it take too much time to make? I’m really not able to do something like that homemade
wow!! What a beautiful coupler!!!
Will u sell it? I plan to propose my better half soon and this should fit very well!