Question: The project is to rotate a load using a motor with a varying speed between like *2000-10000 rpm*.

I'm using a **flange coupling** to attach the cylindrical tube to the motor. Since I will rotate it to high speed, I think I need to tightly and safely attach the load to the motor. 

Do you have any suggestion on what coupling or what is the best way to attach the cylindrical tube to the motor **safely**?

NOTE: the shaft and load are the same lines. this machine is about centrifugal electrospinning which is a machine to fabricate a nanofiber. 

[![enter image description here](https://i.stack.imgur.com/JsGkQ.jpg)](https://i.stack.imgur.com/JsGkQ.jpg)

Answer: 
One can use the Flange Coupling with Key feature and Axis Support Fixed Seat.

Like this:

[![enter image description here](https://i.stack.imgur.com/qtpBZ.jpg)](https://i.stack.imgur.com/qtpBZ.jpg)

This design includes both. Also, one can find these off the shelf according to dimension requirements, or one can design one of them easily.

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For example: [JoyceDayton](https://joycedayton.com/products/system-accessories/couplings) 

[![enter image description here](https://i.stack.imgur.com/nX6DM.jpg)](https://i.stack.imgur.com/nX6DM.jpg)

For example: [Ebay](https://www.ebay.co.uk/itm/8mm-Flange-Coupling-Steel-Rigid-Flange-Coupling-Motor-Guide-Shaft-Axis-Bearing-F-/222683278447)

[![enter image description here](https://i.stack.imgur.com/vON9es.jpg)](https://i.stack.imgur.com/vON9es.jpg)

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Most importantly, after the calculation of the bolt torques, one can use **lock tight** in order to make sure rigid connection.
The safest way to attach a non-symmetrical load (such as that shown in your photo) that spins that fast (up to 10,000rpm) will be to mount it to a solid base, using bearings or similar, such that its weight is supported separately from the motor shaft. This will minimise vibrations/oscillations of the load.

As a result, there will now be a slight misalignment between the vibrating motor, and the constrained load. Using a a semi-flexible coupling (jaw, Oldham, etc) to transfer the rotation will accomodate this misalignment safely without damaging the motor.

Your biggest worry should be wobble from any off-centre mass of the load, rather than the direct strength of the coupling, per se.