Those couplers are quite good, provided they are a tight fit over the rubber.
Personally, I would aim for a GT2 belt reduction, but in the meantime ...

Cheers
Roger

Hi,
yes they'll do fine if there a sung fit. The 'lost motion' due to torsional flexure of the cheap couplers is 4um.
Quite frankly chasing 4um is not high on my list of things to do.
With the 10:1 gearbox my steppers are rated at 705oz.in With a 5mm pitch ballscrew of 20mm diameter that means a
rated thrust of 1480 lbf! I need some sort of mechanical fuse and the wee couplers do the job well, it was not my
intent, it just worked out that way. I don't want couplers such as the ones you've pictured, it would mean a blown
gearbox if I had a crash.

Craig

Without a gearbox, a crash should just cause the motor to skip.
I think it will be a good idea to design a failsafe element. Thanks for mentioning it. I will put it in the back of my head as something to work on.

Hi,
I note you were talking 34 size steppers which could easily be 700 oz.in without a gearbox and therefore capable of 1500 lbf
at stall. 1500lbf deserves respect.

Craig

Hi,
I note you were talking 34 size steppers which could easily be 700 oz.in without a gearbox and therefore capable of 1500 lbf
at stall. 1500lbf deserves respect.

Craig

I've rethought the 34's. I have a plan for 23's with 430 oz/in which is still finger breaking territory.

Well, I've ruled out the power supply and released the magic smoke from my BoB.

I bought a new 48V power supply and hooked it up. I started the X motor cycling and then ran a G-code.
The stepper dropped exactly the same steps as when using the 24V power supply.
In the process, I forgot my BoB was only rated for 24V through the relay and connected capacitor and, well, a loud POP and the capacitor smoke released.

The BoB still worked with the blown capacitor though. All is not lost on that board. I can always solder on a new capacitor and I have two other boards.

So, different motors, problem exists.
Different BoB, problem exists.
Different Power Supply, problem exists.

Next is drivers but they be spendy.

Here I am, back at my project after a break to start a new job and fight off a weird, sudden, pinched nerve issue in my back.

Anyhow, I purchased Gecko 201X drivers and tried to hook one up. I'm sure I have a few things wrong because it functions worse than the cheap Chinese ones.
It's jumpy and resonance is insane. And it made my stepper get super warm, super quick. I finally shut it down after about a minute of tinkering.

Much more reading will need to be done before I can feel confident that this is going to work.

You must be DEFINITELY doing something wrong with the Gecko. They are very good drivers.
So - read on and check. You will find it.

Cheers
Roger

I do know the first time it was hooked up I had left the dip switches alone and in factory position. That sent 7AMPS to the steppers that are rated at ONE. So that's wy the stepper got hot fast.

Dropped the dips down to the one amp that I need and tried again and the driver started to smell right off. I shut it down and checked the wiring to make sure I have it right. I have it wired right, I assume, based on the manual that came with the drivers.
I also noticed the power supply was dimming like there was a direct short and pulsing about one dim cycle per minute. This concerns me greatly as I noticed the LED on the BoB dimming as well.

I disconnected the positive (Vcc) from the gecko and then turned on the power and the BoB was fine.

I'm going to have to break out the multi meter to check everything before I try again.

One thing to remember: if you have damaged the Gecko 201X, contact Gecko about a repair. They are very, very good about that.

Cheers
Roger