Learning the nitty gritty of CNC parts

I have always wanted to make chips fly with the assistance of a computer. In the last couple of months I have gotten a little more serious about the idea that I can both afford and have space for a CNC router. After reading through the reviews, watching videos, and thinking about what I would mainly use the tool for, I have come to the MPCNC as my number one choice. Simply put I need something small and cheap as my first attempt at a CNC.

With before I start printing the parts on my printer, I need to purchase the rest of the hardware. I have a pretty good understanding of electronics as I have a background in cyber so it is at least a similar language, but I want to really understand motors, control boards, and drivers. I have found a few articles online but I am trying to learn how to read part numbers, how to search for parts (sourcing) and how to design the electronics on paper. I can type nema 17 into aliexpress, ebay, or amazon but how do I find the right motor for me?

Examples of specifics I have questions about:
Gt2 belt - what does Gt2 stand for?
F623-RS Bearing - what does the F623-RS stand for?
17HS4801 motor - what does the HS4801 stand for?

While the answers to the above questions would be helpfully, I more so want to learn how to lookup that information. Every time I try to search for more info about the part I just get more ads to buy it! Any help would be greatly appreciated!

Don’t overlook the V1 shop as a resource. Parts that may carry the same P/N are not always equals and Ryan sells quality parts at reasonable prices.

While buying the kit would be an easy step in this process, I want to understand the machine as best as possible. I want to know each part of the machine, not just build it.

Corrected from @Mcunn response below: GT2 means Gates Tooth 2, the 2 is the tooth pitch on the belt.


On bearing designations, go back to a time before China made stuff, each big OEM of bearings had their own code system to designate bearing sizes, and you’d get these books to cross ref from Timken to SKF etc. About the biggest of these is SKF, 608-2RS is is SKF designation. Now with China making stuff they appear to have settled on the SKF system.

Refer to this on breaking it down:

Basic bearing designation system | SKF

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This is awesome! Thanks for the breakdown

I was under the impression that gt stands for gates tooth which is the patented tooth profile it uses.

worldwide.espacenet<insert .com>/patent/search/family/024982636/publication/US5807194A?q=pn%3DUS5807194

Here is the patent for it. I have not found an article yet that goes either way.

The forum will not let me put links in

Here ya go:

Thanks! I’ve got some research to do now. Still trying to understand motor sizing. I understand the mounting dimensions (Nema 17,23 etc) but not the rest.

Your example NEMA stepper HS4801 is a part number from a specific manufacturer not a specification

There is a code structure:


But I’m not sure if the cheapo stepper motors follow it.

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For stepper motors, @Mcunn’s comment matches my experience. You’ll need to take that part number and visit the supplier’s site where you’ll find a data sheet with the rest of the motor’s vital statistics. Probably two most critical are the holding torque and the max current. For steppers, Holding Torque is specified, then torque drops off as RPM increases - the stats may also include a torque curve so you can see the relationship visually. For the MPCNC, check the torque specs on the motors in the store that @vicious1 includes in the kit , then meet or exceed the torque spec if you’re sourcing your own.

It’s pretty common to run these motors on a pretty wide range of voltages (which is supplied to the motor controller board), and the drivers then manage the maximum current sent to the motor. The driver may have a potentiometer to turn (A4988, DRV8825, etc.) for tuning with a multi-meter, or they may use “digipots” where the current is set in the firmware configuration. @vicious1 has already got good starting points set in the firmware for the boards he carries that use digipots.

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Thanks everyone for your help. Was able to go through everything and purchase all the supplies I think I need. We will see when everything starts arriving and I start building! Now time to see if the 3D printer works :wink:

Best of luck! Don’t hesitate to ask for assistance if you hit any snags.

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