This is DIY CNC Interval 2B – Linear Motion Bearings, Motor & Coupling Selection.
Linear Motion Bearings , Shafts and Support Blocks
For linear translation support I decided to go with 20mmm (dia.) Linear Motion Ball Bearings mounted on 20mm chrome shafts. Per axis 4 Linear Motion Bearings will be used.
Open Type Linear Motion Bearing:
Closed Type Linear Motion Bearing:
The Linear Motion Bearing Stock:
To support shafts I have got some Shaft End support blocks:
Shaft End Support Stock:
20mm Chrome Shafts:
Stepper Motors
I’ve also purchased 3x Nema-23 18.9 Kg-cm Torque Stepper motors which provides enough torque to mill metals like Aluminum given a proper lead screw is used.
Couplings
A Nema 23 Standard Stepper motor shaft has a diameter of 1/4″ i.e 6.35mm. On the other hand my Lead Screws are 10mm in diameter. Hence I wanted a coupling which can couple the 10mm lead screw with 6.35mm stepper shaft. Once such type of coupling was available on Ebay – HongKong but then I found a fabricator who could flexible shaft couplings at almost the same price. Within 5 days I got it fabricated from Excella electronics – Ghatkopar , Mumbai.
Misc
Also got a sample of pillow block bearing which I had originally thought of using as end support for Lead Screw. This might or might not go into the actual CNC.