Steel-Core Belt Upgrade

Back when I had one of my belts snap I was talking with a contact I have at another company I work with and he showed me these steel-core belts vs having fiberglass core. So I decided to give them a try:

Right away the belts rigidity was on a whole nother level from the original belts that ship with the Shapeoko. Because they were a lot more rigid it was a bit more difficult to get them installed through the idle bearings and onto the timing pulley but I was able to get it with a little finagling. Here is what my current setup looks like now:

I have more to update on with that Z axis I built (albeit not well) to support the 2.2kw spindle using a 110v VFD but that is a long story of frustration. It is worth mentioning tho that these belts are showing significant improvement in the overall movement of the machine while in operation and in just jogging. I am HIGHLY impressed.

It is worth noting that if you order the ones I have linked above be prepared to wait at LEAST a month for them to arrive unless you pay for faster shipping.


In what ways are you seeing improvement?
Thanks for sharing!


I just noticed the steel belt version of the belts a couple weeks ago, but finding them in 9mm seemed to be a bit challenging. Thanks for sharing!

1 Like

Have you been able to quantify how much they stretch (less) compared to the original belts ? Or what exactly is the nature of the improvement? Just being curious and quite interested by this upgrade potentially


I have thought about experimenting with steel core myself someday.

One thing to note, as the Shapeoko is using low tooth count pulleys and idlers to increase the amount of belt to pulley engagement, it creates a very tight radius for a less flexible reinforced belt. This could cause the steel-core belt to wear and fatigue more quickly than the fiberglass counterpart. Be a matter of outweighing if the shorter life span is worth the increased rigidity (increased accuracy and potentially faster acceleration/deceleration).


Nothing scientific per say but where visibly I could see the belt move left to right while the machine was on and moving that has been eliminated and audibly when I could hear the chatter in the machine whether cutting aluminum or acrylic is now unheard.

All very good questions and I apologize I have no time to get into the nitty gritty outside of what I just mentioned. This is due to the fact I had to just move my whole office/shop and house so I am slammed.

Interesting, I will definitely keep you all posted where I can to see if this happens. So far so good

No pb, anyway I ordered a roll of these to test them myself out of curiosity when I saw your post :slight_smile:
I do not care about possible shorter life span, I’m more looking for precision / more calibration-friendly belts (that stretch less and possibly more linearly)

And 18$ is cheap enough to experiment without thinking twice (until I upgrade to linear X & Y axis one day that is!)


Follow-up: I ordered them on New Year’s Eve, added 6$ for fast shipping, got them about 10 days later, and installed them tonight. First surprise, they are not kidding about the steel core, it took a very significant force to cut it ! You can see the steel wires in the section below:

Assembly was uneventful,

And indeed they feel/sound right when fast jogging, now I’ll proceed with some actual tests, beginning with recalibration across the work area.


Got mine about the same time, but I’m not sure when I’ll have time to install. Looking forward to your tests.

1 Like

I noticed the same thing when I went to cut mine. Definitely some serious steel core :D. I definitely look forward to seeing your tests. So far so good over here and I virtually have zero chatter, BUT, I also am using the 2.2kw spindle now too.

1 Like

Ordered mine in late december - came today. Kinda slow.

1 Like

Subscribed, interested to see how these work.

edit also ordered a set

1 Like

Just finished this big job of a 24" x 24" .5" piece of clear cast acrylic. Went really well :smiley:


Looking forward to seeing your results. I ordered some today paid the extra shipping.

1 Like

Interesting discussion and link on reddit:

Overview of materials at:

1 Like

Now I want to find Kevlar belts, lol. So far so good with my steel ones though.

If anyone has ideas about what exactly they’d like to see tested, let me know. If time (and motivation) allows I’ll check it in addition to my own tests (which will boil down to mapping the X/Y calibration factors at various places of the bed). Also I have not had the time to do these tests BEFORE the upgrade, so the results will not mean much anyway in terms of comparison vs the original belts.


Perhaps using a dial indicator to see how accurate the steps are before and after, if any tweaks to the GRBL settings are needed. Outside of that I am cutting acrylic and aluminum sheet metal all day with mine with no issues so far.