AltMill CNC Update: What's New?

Hi folks. Andy and Daniel are here to share an update on the development of the AltMill CNC!

To find out more, check out our video and blog.




This is what I’ve been waiting for. If this turns out as well as it looks like it is, this is going to completely change the game for entry-level CNCs.

I live close enough that I’m definitely going to make the drive to check this thing out when you have one in the shop.

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Welcome to the group, @jaydillyo!

I’m wondering if it will compete with and be priced more like a OneFinity? Not sure if that’s still entry-level as the price of a OneFinity was quite a bit more than a LongMill last time I checked. It’s definitely interesting in any case.

EDIT: I missed the price when I skimmed the article, but I now see they had an estimate that is more inline with the OneFinity.

I’m wondering if it will be competing with the C3D 5Pro? Feature for feature? Looks interesting, but so does the Shapeoko. Only now I’m afraid of the 5’s electronic problems. Could this happen here with this machine? How good is your QC? C3D’s QC is sadly short in important ways.



See previous post(s), please. QC is not something we hear about, but is very important. We do not know how well the systems you folks put together are tested before we get them. Hopefully, we’re not part of the QC process … oh, wait. :smiley:

Hi Tex, sorry I’m not the one able to answer your questions on this one since the AltMill is not a project under my wing - but I did inform the relevant people including @andy


See previous post(s), please. QC is not something we hear about, but is very important.

We do not know how well the systems you folks put together are tested before we get them.

Hopefully, we’re not part of the QC process … oh, wait. :smiley:

Wow! Since @andy hasn’t seen these posts (but has logged in), my mind wanders about Sienci’s QC procedures.

Perhaps QC is performed by the outside vendors? (I think that is what caught Carbide3d recently.)

Or, maybe there isn’t much QC (in depth, anyway) on Sienci production lines to speak of.

I’m inclined to be generous and imagine that these posts have just been missed. A corporation as large as Sienci must have QC procedures in place, and I’m hoping they are very detailed and test each and every function of every product (because vendors / suppliers can be purty slippery at times.)

@chrismakesstuff QC is still very important to customers. (Carbide3D still has customers getting their very latest / largest CNC with debilitating problems.)

Hi Tex,

Apologies for the very delayed response on all of this - we’ve just finished our final few moving days between office buildings and haven’t had much time to sit down to address your inquiries.

The AltMill aims to target the more ‘prosumer’ audience of makers, within which C3D’s 5 Pro does fall under. We aren’t necessarily looking to match anything specifically ‘feature for feature’, but rather improve on the performance of the LongMill platform and offer this at a 4x4 size.

With regards to some of these QC aspects, we’ve always made sure to be diligent with QC standard procedures for our LongMill, and quickly offering support or replacements for any outliers in this.

For an upcoming product like the AltMill, it’s still a bit too early in the product development phase to tell you exactly what these procedures and systems will look like, but you can be assured the necessary parts and assemblies will be well tested before anything ships out. To answer your last question - our internal QC team handles this quite rigorously. Even when suppliers will assure us of parts that meet our specifications, we always check these for fit and functionality ourselves.

We try to be as transparent as possible about this sort of stuff, so you’ll likely see more on this topic in the near future as development for this continues. Let me know if there’s anything else you’re curious/interested in seeing and we can hopefully address this in future development updates.


Thanks, Molly. Just a bit more, please.

With C3D’s 5 Pro’s current problems in mind, I’m wondering if you folks can/will be able to track problems that occur back to a particular QC session? Its an important function to know when/where a problem occurs e.g. worked during QC, but not for customer.

I understand you’re in “early” stages, but you’re marketing says that you are in production. So, if an electronic board that drives stepper motors smokes or just doesn’t respond for the customer, how would you decide that the customer did it or whether the QC missed something very important?

I understand that this is extremely hypothetical at this early stage, but it happened to C3D’s 5 Pro and continues to happen with their support group sending replacement parts out like a shotgun on a shooting range.

There are a lot of different methods/processes we can use and currently use with the LongMill for tracking issues such as version control and batching. All of our QC is done in-house for the LongMill, even if there are QC processes implemented outside of our shop as well since outside QC is generally unreliable. It should be noted that our primary goal for doing this isn’t to determine if a problem was caused by a user versus a manufacturing defect, but to identify issues in production to address them for the wider batch. For us, there’s less of a need to make this distinction because we believe that we can implement better designs to avoid having user-created issues, which is why for the LongMill, we’ve moved to certain changes to improve the assembly process such as using M5 hardware on the couplers and locking collars which are almost impossible to strip compared to the original M3 hardware.

There are a lot of design features in the AltMill that address the variability of the parts, such as the straightness of the extrusions and mounting of the linear guides that we discuss in the video. Additionally, since many of the major parts need to be pre-assembled precisely in-house, we can test the machine before it gets shipped.

There are a lot of things that could go wrong, so the initial batch size is small. We anticipate there may be some issues initially, and we will spend more time with the machine and each customer than usual before going into larger-scale production.

We generally post photos of jigs and stuff in the Production update blog posts and AltMill updates will have more info about the production process. Many of the QC processes are shared or similar with the LongMill, so much of the experience will carry over to the new production.

This is a pretty large/broad topic that is a lot to get into in a blog post but we can talk about this further in future updates and get into more specific processes for different assemblies and parts.


Thank you for showing that much insight into your ongoing processes. It isn’t something that many manufacturers share in public (probably to be wary of a competitive advantage), but it should be described somewhere so we customers can hold yer feet to the fire on occasion. :smiley:

We’ll look forward to even more details as your production progresses.

Andy and Molly,
As a Manufacturing Engineering Tech before retiring, I am curious as to what QC standards are you using for your machines?
Many of us were in Manufacturing or Engineering prior to retirement and it is just a curiosity to know because of that past. Also, it is a great selling point too.
Thank You!

I just got a z-plus from shapeoko assembled backwards… the bar is low, watching this closely.

What!? How do you assemble backwards? :frowning: Inquiring minds wish to know!

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The mounting plate was flipped so the linear rails/bearings were on the wrong side, limit switch on the left instead of right… they probably didn’t mark front/back before assembly.