Maybe some more details about the project.

@droftarts excellent, thanks. Missed that post in my abscence.

@droftarts thankyou i would do that

Late to the thread, but very sorry to hear. His work (and the time spent documenting his work) was greatly appreciated.

@droftarts Do you choose to mark the issue as resolved?

@Harrison While this forum is for 3D printers, it is focussed on Duet3D controller boards (as distinct from Arduino-based boards) and RepRapFirmware (rather than Arduino firmware such as Marlin). You will probably be better served by posting on the RepRap forums, perhaps in this section: https://reprap.org/forum/list.php?160

However, these are the main thing you should look at:

How is your Arduino connected to the A4988 stepper motor drivers? Usually, an extra board is plugged into the Arduino to make it easy to connect the stepper drivers and motors. For the Mega 2560, it is usually the RAMPS board: https://reprap.org/wiki/RAMPS_1.4 (there are later and earlier versions, but this page has a lot of information on the next points, too). Check that the phases of the motor are connected to the correct outputs of the stepper driver. See https://reprap.org/wiki/RAMPS_1.4#Motors. Check the motor current setting, which is done using the trimpot on the driver. See https://reprap.org/wiki/RAMPS_1.4#Drivers and/or https://reprap.org/wiki/StepStick#Adjusting_and_testing_the_current What firmware is the Arduino running? Make sure the pins definition in the firmware matches the pins you are using to connect the stepper drivers How are you controlling the motors? If you're using something like Pronterface and sending Gcode, you may need to home the axes, or set their position (usually something like G92 X0 Y0 Z0), before the motors will move.

Hope that helps.

Ian

@baird1fa for smoothly accelerating or decelerating motion the time t of the nth step pulse measured from the start of the move is given by this formula:

t = t0 +/- sqrt(q + p * n)

where p = 2/a, q = t0^2

where t0 = -u/a, a is the acceleration and u is the initial speed.

@oliof thx!

My big secret is to tin the wires first. After stripping the wires, apply some flux so the solder will stick easily and tin the wires. I like flux pens like these: https://www.amazon.com/Soldering-Electronics-Tabbing-Welding-Maintenance/dp/B0953NGKXR. TInning without flux is a big pain. And the pens are great for working on PC boards if you do that.

Once both side have been tinned, the two sides will stick quickly. And use heat shrink tubing.

Not quite related, but if you expect the wires to be flexed at all during use, I highly recommend silicone insulated wires. The insulation is flexible and usually the strands of the wire are very fine so the whole thing will be flexible. https://www.amazon.com/BNTECHGO-Silicone-Flexible-Stranded-Tinned/dp/B09X45RZCQ It's not super cheap, but after debugging two cases of thermistor wires broken inside a cable chain I decided to take the plunge and I'll never use the cheapo stranded stuff again.

Lastly, a good soldering iron is a good investment. I have one like this that I like: https://www.amazon.com/dp/B07Z3KCVCL

PS - and get a little tub of tip-tinner to refresh the tip of your soldering iron when it becomes hard to melt the solder on it. https://www.amazon.com/Thermaltronics-FBA_TMT-TC-2-Lead-Tinner-Container/dp/B00NS4J6BY

My experience with cheap pulleys sourced from China is that the holes are either too large or off center resulting in unwanted motion of the printer mechanism. Idlers that have built-in bearings typically have very small, low quality bearings that won't last, and are likely to have the same off-center hole to mount the bearings. Filastruder sells Gates pulleys that are properly drilled for about $5 each.

If I wanted a toothed idler I would probably buy a Gates pulley, insert a shaft, and mount it in an assembly that uses larger ball bearings. Otherwise, if you don't need toothed idlers, stacked F608 bearings make great pulleys for 10mm belt. They are cheap and will probably last forever in a 3D printer. I've been using them in my printer for 6 or 7 years and they show no signs of problems.

@dc42 OK, Thanks for your suggestion, i will have a try.

@Phaedrux
This is the printer I recently swapped out a duet2 for duet3. Still tweaking things and haven't gotten to the point of backing it up yet. But as I am close probably should have backed it up two weeks ago. 😞

Thanks for the help!

@Ilya RRF uses FreeRTOS, see https://github.com/Duet3D/FreeRTOS

Yeah, I think I will order some holy magnets. Very annoying though - it's only two of the 8 magnets ....

@droftarts Thanks!