Junk yard cnc

Hi all,
I’m new to this and I need your help.
I’m trying to build my CNC out of salvaged parts from an old photo copier.
I’m using 3 x kh42jm2 Servo ltd stepper motors ( see attached photo) and an Arduino Uno.
I have many questions if you can help me figure this ;
What’s the best solution, easy driver or big ed, …or CNC shield with ( drv8825 or a4988) ?
Proper power supply? how to set current?
Better use belts or threaded rods?
Can it perform 3d engraving on wood ?
What software should I use ?
( turbocnc- Ncstudio- jscut- mach3-… or just ugs).
If it works I’ll attach a router, maybe a laser or maybe swap between them.

I don’t have that much technical background but will appreciate your help

I think the torque is not enough for a CNC (the drill one), 3D printer or laser engraver, yeah AFAIK. But CNC (the one with that drill type thing that makes cuts) requires torque. You may need to apply some physics to increase torque via pulleys via belt drive as this motor has low torque.
If you want, give it a try but beware, it may not work, don’t get disheartened. I making my 3D printer from scratch for 2 years now, limited resources and time.
Be ready to tinker and play around. make your design on a paper, graph paper preferably; make calculations about your weight and force and stuff. You may be able to get away with it.

Have fun!

Thanks for the tip, I just need it to work properly and accurately first then will figurethe alternatives

Image from Original Post so we don’t have to download it. See this Image Guide



If you can find a link to the datasheet for your motors it would help. The label says 1.2 amps so either an A4988 or DRV8825 should be fine. The DRV8825 has a slightly higher current capacity so it would be my choice.

You might like to consider a program called GRBL that works on an Arduino.

Stepper Motor Basics
Simple Stepper Code

Thanks for your help,
for the record I have all those software I mentioned including grbl and UGS
here is what I found about the motors
and I have two more of : Kh42JM2B087 DC 6.7V 1.2A 1.8 DEG
1x KH42M2R001 DC 3.5 1.7A 1.8DEG
1x OKI (AX04 0121A DC24V 90ohm 7. 5 DEG)
1x (AX04 0122 DC15 30 ohm 7. 5 DEG)

I really like the bCNC program for sending G code to my Grbl based CNC Dremel mini router.

Thanks for the tip, I just need it to work properly and accurately first then will figurethe alternatives

From experience on projects like this, I can tell you that mentality of thinking will cost you extra time and money.
Information on this is plentiful out there now, so decide what material, material thickness, and size you want to work with now because it will effect the size router (if you go that way) you use. The size router you use and material will decide the strength of the rails and motors you need.

Search "DIY CNC" on youtube. There are tons of videos like DIY Cheap Arduino CNC Machine - Machine is Complete AND Accurate! . Not exactly what you are going for, but you can see the strength of his setup as he points out a solution. Imagine having a router pushing instead of a pen on the z-axis. If you end up jumping in and building something like that and want to engrave 3/4" hardwood or something, you will be disappointed and at square one again.

Also, you might look to CNC forums for help on structural and power requirements.

Why did I get this warning when uploaded Grbl?
Low memory available, stability problems may occure

Post the text of the warning. It is probably OK. The IDE puts up that warning if over half of the SRAM is used so there may be plenty SRAM left. I don't remember if I got that warning or not, but I have installed Grbl on 2 different Unos and they both run fine.

Sketch uses 30374 bytes (94%) of program storage space. Maximum is 32256 bytes.
Global variables use 1633 bytes (79%) of dynamic memory, leaving 415 bytes for local variables. Maximum is 2048 bytes.
Low memory available, stability problems may occur.

I just uploaded the version of Grbl (GRBL_VERSION 0.9j), that I use, to an Uno to see how much memory it takes. Below is the report that I get.

It has been working fine for 3 months of almost daily use on my router. I used IDE version 1.6.7.

Sketch uses 28,844 bytes (89%) of program storage space. Maximum is 32,256 bytes.
Global variables use 1,486 bytes (72%) of dynamic memory, leaving 562 bytes for local variables. Maximum is 2,048 bytes.

Where can I find Grbl v, 0.9?
I got this release v 1.1 from here

There are archived versions available from that page. I did not know of a new version. What I have works great so I never looked. I will look at the new one to see if there are new features.