Resources and BOM: https://drdflo.com/CNC-Mill.html
Dr. D-Flo's Instagram:   / dr.dflo  
D-Flo’s Amazon Store: https://www.amazon.com/shop/dr.d-flo

Past Upgrade videos:
CNC Mill Upgrade 2:    • Power Drawbar and Tool Offsets (DIY C...  
CNC Mill Upgrade 1:    • AC Servo Motors and FogBuster Mist Co...  
CNC Mill Conversion Video:    • How to Convert a Manual Mill to CNC  

Products:
Marathon Y551 Motor: https://geni.us/Marathon-Y551
DURApulse GS20 Drive: https://geni.us/DURApulse-GS20
Koyo TRD-S2000VD Encoder: https://geni.us/Koyo
Through-Hole Straight Taps: https://geni.us/Chip-Clearing-Tap
Blind-Hole Spiral Taps: https://geni.us/Spiral-Tap
Taper Lock Pulley: https://geni.us/HTD-Pulley
1610 Bushing for 7/8" Shaft: https://geni.us/Bushing875
1610 Bushing for 40mm Shaft: https://geni.us/Bushing-40mm
Common tools and supplies: https://dflo.info/Amazon

Sponsor: Shop AutomationDirect for all your CNC needs: https://www.automationdirect.com/

Description:
Synchronous feed tapping, also known as rigid tapping, is a computer controlled tapping process that can seamlessly and rapidly add threads to holes. During the rigid tapping process the feed rate of the Z-axis is tied to the rotation of the spindle, such that the tap advances its pitch every rotation of the spindle. To enable rigid tapping on a milling machine, the mill’s controller has to be able to precisely measure and control the spindle speed at low RPMs. These two requirements can be satisfied by using an encoder to track the angular velocity of the spindle and a vector Variable Frequency Drive (VFD), which can change the frequency of power supplied to the motor to modulate its speed.

However, a problem arises when general purpose AC motors, like the one that comes stock on the PM-833TV, are run at low speeds due to inefficient cooling. These types of motors have a fan attached to the backside of the shaft and low speeds result in less airflow. To circumvent this problem, an inverter duty motor (sometimes called a vector motor) should be used instead for low RPM applications like rigid tapping. Inverter duty motors are built out of cast iron (more conductive to heat) and are rated for higher temperature applications. They do not have a shaft mounted fan and can operate at any RPM from 0 to their base speed.

In this video, Dr. D-Flo installs a Marathon Black MAX Inverter duty motor, a DURApulse GS20 series VFD, and a Koyo encoder to his PM-833TV CNC converted mill to achieve rigid tapping in his garage. This video covers this entire upgrade from making a new motor mount for the beefy Y551 motor all the way up to programming a VFD.

Table of Contents:
00:00​ - Introduction
01:11 - Tapping and Threads
03:03 - Tension Compression Tapping
03:25 - Thread Milling
04:25 - General Duty Motor
05:36 - Marathon Inverter Motor
07:52 - Motor Mounting Plate
13:07 - Taper Lock Pulleys
16:40 - DIY or Buy? CNC Mill
17:50 - Belting
19:15 - Installing Inverter Motor
21:47 - Accuracy of Stock VFD
23:22 - AC Motor Control
27:43 - Selecting a VFD
29:59 - Installing New VFD
35:28 - Testing VFD
37:54 - Spindle Encoder
41:21 - Rigid Tapping Testing (Wax)
46:46 - Types of Taps
47:21 - Rigid Tapping Testing (Metal)

#CNC #Tapping #Milling