Your Guide to
CNC Drive Components

The idea of a CNC drive system is a fairly simple one. However, the actual mechanics evolved can be complicated. This is where many "DIY CNC'ers" get lost. The drive system is a direct correlation to the machines capabilities.

By understanding the CNC drive system you have a much better understanding of a CNC machine. Just by changing a few components you can control the machines cutting speed, cutting force, precisions, and accuracy; which should be taken into consideration.

If you are buying a CNC machine, it is best to know what type of drive components are installed. For example, if someone quotes a precision of .0001 inch and then informs you they have standard ACME screws and no anti-backlash nut installed, then they are probably over stating the machines capabilities.

Again, this is especially true if you are buying a used machine. You need to know what kind of components are installed, how much wear they have, and could you buy replacement parts if needed.

What will this guide do?
This guide offers detailed information on every component that makes up a CNC drive system. If you are building a CNC router, we will discuss money saving tips and options as well as assembly. If you are interested in Buying CNC drive parts , then visit our store or take a look at our links page. There you will find a list of recommended places to buy each part.



1. Stepper Motors and Servo Motors
A CNC machine wouldn't be a CNC machine without some sort of motor. Stepper motors or Servo motors both perform the same task, which is take in electrical power and convert it to rotational motion. Think of the motors as the workhorse for the machine, however, they need to be told what to do, which is the job of the CNC controller. This section will take you though the ins and outs of CNC motors.


2. Leadscrews and Ballscrews
The first step to converting the rotational motion supplies by the motors to linear motion, is the lead screw or ball screw. With the help of a CNC drive nut, you can have a great amount of linear force with little torque. Just like the jack on your car. Try to lift your 2000 lb vehicle without the aid or your jack and see how far you get. However, there are many different types of leads crews and ball screws. This guide will walk you through the pros and cons of each type and also discuss alternative solutions for CNC machines on a budget.


3. CNC Drive Nuts
The drive nut is the one link between the lead or ballscrew and the actual machine. Therefore it is often discussed in direct relation with the leadscrews. However, you may have the nicest system money can buy and less than par drive nuts, and not be able to hold a tolerance of .01 inch. That is why I am devoting a full section to drive nuts. This one component will make or break your machine. We will discuss the types of drive nut, backlash and much more. If you are building a CNC router, you MUST read this section. The CNC drive system is a vital part of your machine. I will discuss how to obtain some very nice anti-backlash nuts for very cheap.


4. Rack and pinion
Rack and pinions are less pronoun than their leadscrew counterparts. However, there are some applications where it is the only solution so that close tolerances can still be held. Many hobby CNC'ers completely overlook this option, primarily because of cost. However, there are ways to come out even cheaper than alternative solutions.


4. Radial, Thrust bearing and Couplers
This section covers some of the minor components in a CNC drive system. Things such as radial and thrust bearings for leadscrews and and shaft couplers. Although, these are "minor" pieces in the whole system, they still play a vital role. After all, a machine is only as good as it weakest link. If you are buying a CNC router then you have nothing to worry about as these parts are usually all the same. However, if you are building a CNC machine, this section will cover vital information that will save major headaches down the path.


5.Direct drive vs. Geared or Pulley Systems
There are two main ways of coupling your electric motor to the other CNC drive components. The first being direct drive via use of a anti-backlash shaft coupler discussed above, and secondly, the use of either pulleys or gears. We will cover the reasons for having each and also the pros and cons as usual. This is another one of those things that people often overlook.

Continue to The Builders Guide STEP 5: The X, Y, and Z axis



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