# Stepper motors ‘hissing’ **URL:** \ **Category:** ❓ Something's Up\ **Created:** [June 8, 2026, 10:18am UTC](https://forum.sienci.com/t/stepper-motors-hissing/26539 "2026-06-08T10:18:04Z")\ **Posts on this page:** 8\ **Page:** 1
**Author:** ![guy559](https://forum.sienci.com/letter_avatar_proxy/v4/letter/g/50afbb/32.png) [@guy559](https://forum.sienci.com/u/guy559)\ **Post date:** [June 8, 2026, 10:18am UTC](https://forum.sienci.com/t/stepper-motors-hissing/26539/1 "2026-06-08T10:18:04Z")
New AltMill 2x4 user here. Assembly went well overall and machine operates as expected so far. Still dialing in some things as I schedule around travel. Only oddity so far is the hissing coming from the Mk2’s closed-loop stepper motors. They don’t seem to get hot, but it is pretty loud and noticeable when environment is quiet. The sound comes from all the motors when idle…and ceases when I press e-stop to disconnect stepper control. I tried changing setting to timeout stepper motors when not being used, but then subsequent movement has problem. is this just the norm, esp with closed-loop motors? ---
**Author:** ![Chucky\_ott](https://forum.sienci.com/user_avatar/forum.sienci.com/chucky_ott/32/8692_2.png) [@Chucky\_ott](https://forum.sienci.com/u/Chucky_ott)\ **Post date:** [June 8, 2026, 11:02am UTC](https://forum.sienci.com/t/stepper-motors-hissing/26539/2 "2026-06-08T11:02:49Z")
@guy559 This seems to be a common issue that most people say is normal. Is it a hissing sound or a crackling sound? Mine does it occasionally, usually the Y motors. It stops if I jog the machine. It may be just the motors trying to maintain their position. ---
**Author:** ![DavidB](https://forum.sienci.com/letter_avatar_proxy/v4/letter/d/76d3ee/32.png) [@DavidB](https://forum.sienci.com/u/DavidB)\ **Post date:** [June 8, 2026, 12:09pm UTC](https://forum.sienci.com/t/stepper-motors-hissing/26539/3 "2026-06-08T12:09:16Z")
Mine as well.. Sometimes I would even just hit the e-stop then re-activate the e-stop and the motors would be quiet again which seems odd to me 🙂 ---
**Author:** ![guy559](https://forum.sienci.com/letter_avatar_proxy/v4/letter/g/50afbb/32.png) [@guy559](https://forum.sienci.com/u/guy559)\ **Post date:** [June 8, 2026, 12:38pm UTC](https://forum.sienci.com/t/stepper-motors-hissing/26539/4 "2026-06-08T12:38:39Z")
Luckily, not a crackling sound. It’s a hissing sound that persists even after jogging the machine. Suspect it’s a closed loop stepper motor thing, as my first open-loop CNC didn’t do this. Suspect it’s something to do with the feedback system for positioning, even though the motors aren’t being told to move. Perhaps it’s something like “hold this exact position” and the steppers are ever so slightly responding to do that. There’s no external force acting on the gantry when this occurs. If I reset after hitting e-stop, the hissing sound starts up again… ---
**Author:** ![Jens](https://forum.sienci.com/letter_avatar_proxy/v4/letter/j/d2c977/32.png) [@Jens](https://forum.sienci.com/u/Jens)\ **Post date:** [June 8, 2026, 2:18pm UTC](https://forum.sienci.com/t/stepper-motors-hissing/26539/5 "2026-06-08T14:18:22Z")
This is precisely what is happening. If you were to slightly twist (by hand and very slightly) the ball screw that is connected to the hissing motor, you will find that it stops hissing. ---
**Author:** ![guy559](https://forum.sienci.com/letter_avatar_proxy/v4/letter/g/50afbb/32.png) [@guy559](https://forum.sienci.com/u/guy559)\ **Post date:** [June 8, 2026, 4:07pm UTC](https://forum.sienci.com/t/stepper-motors-hissing/26539/6 "2026-06-08T16:07:51Z")
I’ll have to give this a shot once I’m back in town. Now I’m wondering if there might be a slight flexion in the gantry or if Y1/Y2 motors are ever-so-slightly out of alignment. I have to imagine that this is a common occurrence. I’d love to be able to ‘fix’ it so this doesn’t happen, especially if it inadvertently causes premature stepper wear. I’ll reach out to Sienci and see if there is an official position. Will report back once I have an answer. ---
**Author:** ![NewsVan](https://forum.sienci.com/letter_avatar_proxy/v4/letter/n/48db29/32.png) [@NewsVan](https://forum.sienci.com/u/NewsVan)\ **Post date:** [June 8, 2026, 4:16pm UTC](https://forum.sienci.com/t/stepper-motors-hissing/26539/7 "2026-06-08T16:16:51Z")
My Z axis motor hissed. It would stop after an e-stop and reset. I got a replacement motor replacement. ---
**Author:** ![DavidB](https://forum.sienci.com/letter_avatar_proxy/v4/letter/d/76d3ee/32.png) [@DavidB](https://forum.sienci.com/u/DavidB)\ **Post date:** [June 8, 2026, 6:07pm UTC](https://forum.sienci.com/t/stepper-motors-hissing/26539/8 "2026-06-08T18:07:29Z")
> [@guy559](#): > > I’ll have to give this a shot once I’m back in town. Now I’m wondering if there might be a slight flexion in the gantry or if Y1/Y2 motors are ever-so-slightly out of alignment. > > I have to imagine that this is a common occurrence. I’d love to be able to ‘fix’ it so this doesn’t happen, especially if it inadvertently causes premature stepper wear. As others have said I really don’t think there is anything to “fix”. Even Avid CNC mentions motor noises that sound like the old computer modems when connecting online. They also said it is normal and there is nothing to fix.