Acorn Build-bench testing complete!

I don’t have a complete cost sheet in front of me but plan on between at least $1000-$1500 CAD. Is it worth every penny? Yes

-CNC12 software licence
-Jog wheel/pendant
-Power supplies for drivers
-mounting panel
-Windows computer
-e-stop button
-Limit switches (I actually haven’t installed my switches or sensors yet :shushing_face:)
-Optional: Closed loop steppers :moneybag::moneybag: or servos :moneybag::moneybag::moneybag::moneybag::moneybag::moneybag:


I was initially going with closed loop but decided to run the open loop stockers with good drivers to get a good baseline. I can report they are working amazingly. Super strong with the higher voltage power supplies and drivers. I am running the DM542T V4.0 on 36 volt power supplies. There is another acorn build happening and Jason is running the 48 volt power supplies to his drivers.

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Ohhh, NICE!!! I seriously considered one of those when looking, but ultimately ended up with the DDCS V3.1 & G540, which is a great combo.


Awesome, glad it’s been working well. After a vac table, new steppers are my next project, which might force me to update the drivers and controller… we’ll see.

@trlwoodworks To be honest, if you are planning an upgrade, the controller should be your starting point. Starting with the steppers is like putting the cart before the horse or like buying an expensive camera body but using a basic lens to bring in the light. Higher quality signal generation/motion control and drivers on the stock motors will get you much much farther than just replacing the steppers.

Other benefits of the motion control upgrade are all of the features that it offers. One example I have is after using the park function at the end of the day, I park the machine, turn off. The next day I power everything back up and my WCS zero points are still saved. I load up material and run program and I’m off to the races. Also true G2/G3 IJK arc movement and that isn’t even the tip of the iceberg of what the Acorn and other offerings in this category have to offer.

And I have to keep repeating that I am in no way trying to slag on the 1F controller or 1F as they provide a great product. However when discussing upgrades, the comparative pros/cons must be mentioned.


@alldaysammyj , I just noticed this on the first pic. Are you running the 2 larger power supplies in parallel? Assume the small one is for the Acorn board.


@Machinist yes the small one is for the Acorn and the two larger power supplies are providing power for 2 drives each. Power supply #1 is X,Y and #2 is Z,Y. They are 36 volt 400 watt 11 amp power supplies.

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Hello, just finding out about Onefinity yesterday. I am a newbie, but wanting to get a cnc router with 4th axis. Have investigated the Centroid Acorn system (went from $300 to $330). It looks great, however am concerned I may get bogged down with putting different pieces together.
My ultimate goal is to make vertical wind turbine blades using a cnc router with 4th axis.
I am also new to CAD/CAM and am just getting started with 3D printing.
I like the option of getting a Onefinity machine without controller and without spindle, and to use the Centroid Acorn along with a VFD controlled spindle.
Is anyone using the Centroid Acorn system to set up a 4th axis?
Would this be too much for someone starting out? Like I said, am a newbie, no significant experience with electronics however am capable of following wiring diagrams and doing wiring.
Or would it be better to start out with machine including spindle and controller, getting used to how it works, then upgrading to Centroid Acorn with 4th axis and VFD controlled spindle?
Thanks in advance.

Begs the question, is Onefinity going to make a 4th axis available?

Doubtful, as the Onefinity controller will not support a 4th axis.

I would continue to research what else is involved with opting out of the 1F controller, as it involves more than just attaching the acorn (or other controller - I am using a Masso G3). You will need to purchase other hardware, and set up wiring for homing sensors, etc… This will add cost, time, and complexity, but there is a great deal of information out there, and through forum members’ contributions as well. I found the entire process rewarding, and a great opportunity for learning, so part of this also depends on the type of learner you are, and how much effort you are willing/looking forward to putting in to the process.


Hey Bill, hey Larry, hey Tom,

I doubt Onefinity will make one available, but the accessory market is full of them.

Regarding the ability of the Onefinity or the Buildbotics Controller to use the fourth stepper driver for driving a stepper in a rotary Axis, see this: ← Roger’s Rotary Setup for Onefinity

The Onefinity CNC machine has three axes, but the Onefinity Controller has four drivers. By default, the two Y Axis steppers of the Onefinity are controlled by separate drivers. But since they’re supposed to always do the same, there exists the possibility to drive them with a single driver (see below). This allows to free the fourth motor driver and to do what Roger @rblur01 has done.

It mainly depends on your CAM software to define the fourth axis as a rotary one.

3.8. Motors


A single output port can drive two motors with certain limitations. It is recommended that the motors be wired in parallel when driving two motors from a single motor output. The limitations are:

  • Since the two motors are wired in parallel, the current supplied by the motor output will be doubled. For instance, if each motor has a current rating of 2.8 amps, then the current on the motor output must be set to 5.6 amps. The maximum output current from a motor port on the Buldbotics Controller is 6 amps, so you cannot connect two motors that require more than 3 amps each to a single port.
  • When motors are wired in parallel on a single output port, they tend to resonate with one another. When the resonance occurs, the motors will stall. As a result, the motors must run at a speed below this resonance to avoid stalls. Unfortunately, it is not possible to predict the speed at which this resonance will occur without wiring them up and connecting them to the machine.

Source: Buildbotics Manual, #motors

@TMToronto made a Y Axis splitter board:


It is possible with the one finity controller without running both wise to one motor but unattaching won the y-axis and using that for the rotary here is a link to a topic that this has been discussed

Hey Greg,

I think so. You could use X, Z, and A, and no Y at all. By the way, I already linked to the same topic above. There is a lot explained if you follow the threads above.

Great it works
I have done it I’m waiting on my journeyman update to show up and the table I’m building for it is designed for the Rotary also a vertical board for dovetails I’ll put updates after that but it’ll take a while my wife is great beautiful but I haven’t got her to build my stuff yet that’s a joke God bless

Others who use the 1F controller may have an answer, or perhaps it is answered already in the links provided earlier, but you may be able to save different machine settings in the controller - to make switching between stock and rotary set-ups easier.

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Installed yet? Or are you manually homing? I never installed limit switches yet on my machine. I home so seldom and it’s actually been very easy to manually move to the hard stops & zero out machine coords.

Yes you can I have a rotary setup and then a regular setup. Once you set them up it’s easy to switch between the two.

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Yeah I am running manual homing. It’s so simple that I would have to be very motivated to install the limit switches at this point. I just park the machine at the end of the day and when I start back up it’s ready to go.

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Yes, THIS. Exactly. I simply haven’t realized the need for it at all. And quite frankly, I like keeping the machine wiring that much neater. Unless I’ve accidentally hit a jog button without motors being powered, then the machine retains coordinates just fine.

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