CNC Machine Mechanical Parts - Lead Screws, Anti-Backlash Nuts, Sprockets, Roller Chains and Collars

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Mechanical Parts for the DIY CNC Machines

Probably the most imporatant part of the CNC Machine and the most challenging to implement. I will try to make it easy for you by offering the common component that can be used in your DIY CNC Router. These parts are especially selected to work with motors used in the DIY community and took me quite a while to find the perfect combinations. Please read the conditions of purchase prior to purchasing any products offered by BuildYourCNC.com.

1/2" Lead Screws and Anti-Backlash Nuts

With our lead screws and lead nuts, the combination is perfectly mated. CNC Machines require precise movement. Backlash occurs in many parts of the linear motion mechanics. With this lead screw and anti-backlash nut combination, you will minimize this backlash tremendously. The anti-backlash is also known as a wear compensating nut. As the machines is used over time, the lead screw may wear, and this nut will mechanically adjust for this wear. The lead screw and nut specifications: 2 turns per inch, 1/2" outside diameter lead screw, 10 threads per inch and has 5 starts (making it 2 turns per inch). The lead screw is ACME precision (same thing as saying the threads are square, not shaped like a "V").

Anti-Backlash Lead Nut

Lead Screw (Steel)

3/8" Lead Screws and Anti-Backlash Nuts

This lead screw and nut specifications: 5 turns per inch, 3/8" outside diameter lead screw, 10 threads per inch and has 2 starts (making it 5 turns per inch). The lead screw is ACME precision.

Anti-Backlash Lead Nut

Lead Screw (Steel)

Idler Sprocket #25

This is the same sprocket that guides #25 chain and drive sprocket. The sprocket has 20 teeth with a .25" pitch and contains an R6 ball bearing with a 3/8" ID (inside diameter).

Idler Sprocket

Drive Sprocket #25 - 1/4" and 5/16" Bores

You need a sprocket that connects to the motor, is small and has the fewest number of teeth possible for the best resolution. This drive sprocket has a 1/4" bore so it will fit most NEMA 23 and 24 motors. The sprocket has only 9 teeth with .25" pitch for a total of 2.25 inches of travel in one turn of the motor. That's 1422.222 steps per inch with 1/16 microstepping and the standard 200 steps per revolution.

1/4" ID Drive Sprocket (9 teeth)

5/16" ID Drive Sprocket (11 Teeth)

Drive Sprocket #25 - 1/2" Bore

You have a motor with a 1/2" shaff and looking for the fewest number of teeth to achieve the highest possible mechanical resolution. The sprocket has 14 teeth with .25" pitch for a total of 3.5 inches of travel in one turn of the motor. Here are the resolutions at varying microsteps (in steps per inch): Full Step - 57.143, 1/2 - 144.286, 1/4 - 228.571, 1/8 - 457.143, 1/16 - 914.286, 1/32 - 1828.571.

1/2" ID Drive Sprocket - 14 teeth

Roller Chain #25

This is the chain that mates with the #25 sprockets. Use this chain to achieve the finest resolution roller chains can offer. The material is steel and the pitch is .25". Each 10 feet of length includes one chain link that can be used to extend the chain.

Drive Sprocket and Collar

Notice the very large bore (hole) in the drive sprocket. That bore won't fit any motor generally used in the DIY CNC community, but accompanied with a collar that reduces the bore, now you have a great combination that fits well with 1/4" shafts. The collar has a 1/4" inside diameter and 5/8" outside diameter. The Drive sprocket has a 5/8" inside diameter with the smalles working diameter in the industry. But the collar screws stick out, you say. No worries, these screws fit right into the keyway of the drive sprocket.

Drive Sprocket

Double Collar

Collar/Sprocket Combo

Idler Sprocket

You can use this mechanism to either help position the roller chain to assist the drive sprocket, or be used as a free wheel for one end of a loop of roller chain. This sprocket has a 5/8" inside diameter and 17 teeth and can be sold with the 5/8" bolt and nut if desired.

Idler Sprocket (No bolt/nut)

Idler Sprocket with bolt and nut

Roller Chain

This is a single strand steel #40 chain that matches the pitch of the #40 sprockets. All links are rivited and can handle 437 pounds of working load.

Roller Chain

Roller Chain 5 feet

Roller Chain 10 feet

Sprocket and chain Combo Kit

Here is a combination of parts to establish a drive system. Included in the kit is a Drive Sprocket, Collar, Idler Sprocket, 5/8" bolt and either a 5 foot chain or 10 foot chain or no chain so varying lengths can be purchased.

#40 Chain and Sprocket kit with 10 foot chain

#40 Chain and Sprocket kit with 5 foot chain

#40 Chain and Sprocket kit (chain purchased separately)

Collars

These parts are typically used to stabilize lead screws (so they don't move axially). Notice the open cut and the screw configuration. This is called the clamp style of collar so that there is a very tight and non-slipping condition and is made of steel. These collars will also reduce the damage on the lead screw by not using set-screws.

1/4" Inside Diameter Collar

3/8" Inside Diameter Collar

1/2" Inside Diameter Collar

5/8" Inside Diameter Collar

7/8" Inside Diameter Collar