Shaft coupling

[Dauph]

Hi all,
I'm attempting to build a drum sander using an old drill. I attached the drill to the drum shaft using an aluminium flexible coupler. It snapped on the first test with barely any load on it.
It was cheap, and did mention 3D printers as a use, so I guess it wasn't up for the speed/torque of my plan.
I found this on Amazon https://shorturl.at/am5Wf It has no reviews but is potentially a better design that what's mostly available on Amazon
I found one that is described as "high torque" but, again, no reviews, and pricey.
Any thoughts/suggestion?
Edit: Photo is of the test set up and broken coupler

 

[ChaiLatte]

Take a photo of your setup showing the failed coupler in place.

You provide insufficient concrete information in your post to make any suggestion any better than consulting tea leaves.

 

[Dauph]

Take a photo of your setup showing the failed coupler in place.

You provide insufficient concrete information in your post to make any suggestion any better than consulting tea leaves.

Done. Please see above. Ta!

 

[Amplidyne]

Try amazon and search "Small Universal joint" Sourcing map have 10 and 12mm joints on there. Should be stronger than the spring type I would think.

 

[Phill05]

I don't think you need a coupler for that direct in the chuck as you show should be fine.

 

[ChaiLatte]

I don't think you need a coupler for that direct in the chuck as you show should be fine.

You are right. The small difficulty is that in the photo the drill is free-floating.

However, as it is a corded item, the collar on it will be a standard 42mm or 43mm (cannot remember which of the two is correct). Making a clamp that restrains the drill and is concentric with the shaft will eliminate the need for a coupler.

Make your best efforts with it, and if it is not quite right when tested, you can sand its base down to lower it or shim it up with paper if too low.

So long as the drill is clamped in place, a real cheapskate option to take out any residual misalignment is a piece of rubber hose joining the drum shaft to a short stub shaft held in the drill chuck. Minimal gap between the two shaft ends. It might act as a safety clutch when your tie gets sucked into the drum.

 

[Dauph]

You are right. The small difficulty is that in the photo the drill is free-floating.

However, as it is a corded item, the collar on it will be a standard 42mm or 43mm (cannot remember which of the two is correct). Making a clamp that restrains the drill and is concentric with the shaft will eliminate the need for a coupler.

Make your best efforts with it, and if it is not quite right when tested, you can sand its base down to lower it or shim it up with paper if too low.

So long as the drill is clamped in place, a real cheapskate option to take out any residual misalignment is a piece of rubber hose joining the drum shaft to a short stub shaft held in the drill chuck. Minimal gap between the two shaft ends. It might act as a safety clutch when your tie gets sucked into the drum.

It was a test set up so I know the drill not being clamped was less than ideal. I did have an F clamp on while it ran. The coupler failed when I tried sanding the drum lightly, so it seems more load related that it failed. I now realise I may have had the coupler the wrong way round, so it was trying to uncoil. Can't have helped! I'd like something a bit more substantial than a bit of tube but, I'll bear it in mind. Ta

 

[Dauph]

Try amazon and search "Small Universal joint" Sourcing map have 10 and 12mm joints on there. Should be stronger than the spring type I would think.

They look much more sturdy. I assume it'll do the same job I.E. make allowances for slight misalignment/deviation and vibration?

 

[ChaiLatte]

...make allowances for slight misalignment/deviation and vibration?

A single universal joint will only allow angular misalignment in one plane.

In addition, in anything but a coaxial arrangement, a single UJ is not constant velocity, so the drum speed will vary throughout one revolution.

It would give you more options with a pair of joints, correctly phased.

 

[Sachakins]

With accurate alignment there's no need for a coupler.