Masso G3 build - Tangential knife success with Sheetcam

It has been a while since I have posted an update to my Masso G3 enclosure build and 1F CNC modifications, but I now have something to share that may interest others.

With respect to the electronics, I have made my homing sensor cables, and added a relay module which at the moment uses the ES (Estop) signal from my controller and two of the relays to trigger the disable on my two drivers. I have also installed my second new driver which controls the 4th rotary (A, sometimes referred to as C) axis. I also installed an IR sensor to home the new rotary axis.

Hardware updates include the designing, printing, and assembling components for the tangential knife I created. The mechanics work well, and it configured easily with my Masso controller.

The final step, which I just today completed, was finding software to create the proper lift and motion direction angle. I learned that Sheetcam (used by many torch CNCers) had a Masso tangential knife PP. I was able to get a temporary evaluation license from Les, the creator (very supportive and helpful), and began experimenting. There were a number of PP to choose from, and today I must have got all the settings to work together because I successfully cut a paper silhouette (I am happy - it has been many hours of work from concept to creation).

I am attaching some pictures of the controller and tangential knife for those interested in a few visuals. Please note that 1) my 1F and controller are still in the testing phase, so please ignore the wiring that has not yet found its final path through wire duct, and 2) the file I chose to cut is, I feel, too detailed for this particular knife (I have plans to build an oscillating version with a narrow blade - but that will be much later).


Hey Tom,

what is particularly impressive is the steep learning curve how you have acquired all of this.

I appreciate the kind words. Although a retired teacher now, I have always been drawn to math, science, and engineering - that and a passion for building things. There is something satisfying about bringing ideas to life. I believe (and hope) that this hobby will keep my brain, and hands, active for a very long time.


I have been experimenting with various parameters. Here are results of cutting a square and star.
Given the blade geometry, there are areas of over travel on the inside angles. My next learning goal will be to see if I can modify the post processor to take this into account. If anyone in the community has any suggestions for good resources that explain how post processors work, and how to create the code, I would appreciate you passing them on. There are many on the internet, but perhaps you know if some are better than others. Thank you.


Nice, will you share the price of going masso cost

Certainly - Masso G3 5 axis version is currently $740US

Thank you I spent as much on laser attachment one more question sir is that complete or will I need a purchase other additions so I can use my CNC machine also rotary attachment

One of the reasons I went with the Masso G3 was the true 5 axis option - X,Y (slaved B),Z, and dedicated A axis for rotary applications (vertical now, sometimes referred to as a C axis, but in the future I plan to add a horisontal rotary axis). I spent the extra up front because I believe this is the only controller I will ever need, it configures easily, having inputs and outputs that will cover anything I wish to add (ATC, spindle, etc). Masso support has been great, especially helpful with my questions concerning electronics as I built my own controller enclosure learning as I went. I upgraded my steppers, so used one of the original ones for my A axis. Keep in mind you will need to purchase drivers for your stepper motors - I prefer this as I can match them to the application and buy a more capable driver. The drivers will also need a power supply. I originally purchased a Leadshine MX4660 that has 4 integrated drives, then added a Stepperonline DM860I for my new A axis - there are less expensive options, but again I chose these components up front to handle any future upgrades I wish to make.


Great ty
Down ty road I will be getting with you if that’s ok

Happy to answer any questions you may have.

Can I bother you for a shopping list so I can start knocking it off

Which components are you interested in?

I’m sorry
Power supply
Everything I’ll need to operate true rotary
I know this is a big request
But you have what I been wanting
Fill free to add advise whatever to help

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Masso G3 *5 axis Mill version
Meanwell SE-600-48 for drivers
Meanwell EDR-120-24 (X2) one dedicated to Masso, one for 24VDC sensors, etc
Meanwell RD-35A dual 12VDC/5VDC for sensors/inputs etc. requiring lower voltage
Leadshine MX4660 for 1F X, Y1, slaved B(Y2) steppers
Stepperonline DM860I for rotary(A) axis
Relay module:
Masso 6 relay module *two relays currently for Estop circuit to disable drivers/remaining four relays will control power for future spindle, VFD, solenoids, pumps, etc
Stepper motors:
upgraded 1F steppers to 420 oz-in 3.0 mH NEMA 23 Stepper Motor, 3/8" Shaft
*note I got the motor kit complete from AVIDCNC which included motors, cables, and PSU
*note that that if you get the 380 oz-in the shaft is 1/4" and you can reuse the 1F motor couplings
*note I used a 1F stepper for my A axis - so far it has enough torque for the application
Homing sensors:

Twidec /M12 Approach Sensor Inductive Proximity Switch NPN NC DC 6-36V, 4mm Detecting Distance LJ12A3-4-Z/AX (X4)

Rotary decoder:
[Robojax Infrared Encoder Interrupter Module WYC H2010 Wide Gap for Arduino and Raspberry Pi]
*note this is needed to home(index) the rotary axis so the knife always starts in the same orientation/degrees direction
*note this one requires 5VDC
Tangential knife:
I designed and 3D printed my own, then built it with other sourced components. I am happy to share the F360 files and parts list if you are not buying one of the available modules and would like to try my design
Cable management:
I am not sure what you will do here. I purchased all the cable and components to make my own sensor cables. I also designed and built (3D printed) my drag chain mounting system, but purchased the drag chain for it. I have shared all my F360 files for this with other members, and am happy to for you as well if desired.
There are numerous components I purchased to complete my controller enclosure build.
I am able to share these if you like. The learning curve for me was steep, but enjoyable and worthwhile - you will need to spend some time researching this topic if not already familiar with this area of electronics.
Let me know if I missed anything.


Holy cow
I’m going to try and see if I can get this figured out
It’ll be a learning opportunity
I’m excited ty
We can not use our motors forthe xyz axis?

Absolutely can use 1F steppers - just need one more and a driver.

Sent: September 17, 2021 9:02 PM
Reply to:
Subject: [Onefinity CNC Forum] [Controller/Aftermarket Controllers (Advanced Users Only)] Masso G3 build - Tangential knife success with Sheetcam

| GregoryG Greg Martinez
September 18 |

  • | - |

Holy cow
I’m going to try and see if I can get this figured out
It’ll be a learning opportunity
I’m excited ty
We can not use our motors forthe xyz axis?

Isthis needed orcan we manually zero the AAxis

Robojax Infrared Encoder Interrupter Module WYC H2010 Wide Gap for Arduino and Raspberry Pi]
*note this is needed to home(index) the rotary axis so the knife always starts in the same orientation/degrees direction

If you are talking about homing the A axis as part of a Masso build, I believe they recommend all axes have a homing sensor. It was inexpensive compared to others I researched, and easy to wire and set up. I just 3D printed the mount and trigger arm once I knew how the mechanics went together. You need one with an indexing output (most only have A/B dual outputs, good for speed and direction of rotation) to set a particular position.

It is great to have, and my knife always stats in a known position and more importantly direction.

I am so ready to make the purchases my only delay sir is I am afraid that I do not fully understand how to hook this up having the CNC machine operate as it does the one finity and also have a rotary attachment which I own I want that very much that was my original plan and still is it looks like you have it I cannot find enough YouTube tutorials or documentation to walk me through the procedure I don’t know if this would be too much bother for you today to do or can you point me in the direction where I could receive the needed education on the procedures once again sir I thank you very much I know we’ll get through this and I promise to pay it forward

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I am always happy to help out. Perhaps breaking it down into steps/parts is best.

Is your main goal to add a rotary A axis?

If yes, is it a vertical application like mine for a tangential knife?

If you want this type of knife you could try a drag knife first. There are many forum members using the various types, and depending on your application, they can easily cut from thin vinyl up the thicker cardboard. You only need to buy the cutter, and possibly modify the post processor to make the correct Z axis lifts for a knife like the Donek. That one is not inexpensive ($249US).

Doing what I did requires at least another stepper, driver, PSU, encoder, wiring, new controller, and software that can generate the g code. If you buy a tangential cutter, like the StepCraft model, you would need to learn how to connect it to your controller, and have software to run it properly.

If you want a horizontal application that looks more like a “lathe” attachment? See image -

. You can do it with the current 1F set up, but it requires you to disconnect and reconnect one of the axes, and probably controller modifications. There are forum members who have done this successfully as well.

Is the goal to purchase a new controller like the Masso, along with a dedicated rotary axis?

If yes then you would need to be comfortable with the electrical work to, at minimum, put together all the components (and associated circuits) I had listed for you earlier.

Then you need to correctly connect all hardware, including running cables for motors and sensors.

Then you need to configure it all in the new controller software.

Then you need you need to make sure you have software that will allow you to design your parts, and software to generate the g code that will run the knife on your controller and 1F CNC.

That is a lot, but possible, as I found out over the last months.

Which of these steps you might consider will depend on many factors such as time, money, skill level with electronics (very dangerous), skill level with Internet searches…and many others. I can certainly point you to some resources as a starting point.

What are your initial thoughts after reading this?

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