JST JGD-125C Water Cooled Spindle

Overview

A 5.5kW / 6kW Chinese water cooled spindle with an ER25 collet chuck. It is marketed for stone engraving rather than CNC routing.

Wiring

Power inlet "WEIPU WS20" circular connector wiring:

Pin	Wire Color
1	yellow
2	blue
3	red
4	(ground)

The spindle has male pins inside an externally threaded receptacle.

Replacement Parts

Angular Contact Bearings

7007C T 2RZ HQ1 P4 DBL Z3X 131018044B

Deep Groove Bearings

SKF E2 6004-2Z/C3 15 260 K

Bottom Locknut

Doubles as a dust shield:

• 56.7mm OD
• 5.1mm thick (dust shield portion)
• 4x 3.5mm holes 3mm deep on a 44mm diameter circle
• must get past a 33.3mm diameter spindle nose before threading into place

Top Locknut

• 32mm overall OD
• 10mm thick
• M20x1.0mm threads on the ID
• 26mm OD / 22mm ID rim for bearing's inner shield
• 1.8mm clearance around the rim for the bearing's shield, as well as a shoulder with no threads on the inside

O-rings

The top cap with the water inlets have 10mm OD 1mm deep recesses with a 6mm ID hole for O-rings. Maybe for one of these?:

• Square-Profile Oil-Resistant Buna-N O-Ring, 1.5 mm Wide, 7 mm ID | McMaster-Carr
• Square-Profile Oil-Resistant Buna-N O-Ring, 2 mm Wide, 6 mm ID | McMaster-Carr
• Oil-Resistant Buna-N O-Ring, 1.5 mm Wide, 6.5 mm ID | McMaster-Carr
• Oil-Resistant Buna-N O-Ring, 1.78 mm Wide, 6.35 mm ID | McMaster-Carr
• Oil-Resistant Buna-N O-Ring, 1.8 mm Wide, 6 mm ID | McMaster-Carr
• Oil-Resistant Buna-N O-Ring, 2 mm Wide, 6 mm ID | McMaster-Carr

The bearing housing portion of the spindle has 8mm OD 1mm deep recesses with 4mm ID holes for O-rings. Maybe for one of these?:

• Oil-Resistant Buna-N O-Ring, 1.5 mm Wide, 4.5 mm ID | McMaster-Carr
• Oil-Resistant Buna-N O-Ring, 2 mm Wide, 4 mm ID | McMaster-Carr (verified)

Fasteners

Dust Shield

For holding the dust shield to the lower angular contact bearing retaining ring:

4x Alloy Steel Socket Head Screw, Black-Oxide, M4 x 0.7 mm Thread, 8 mm Long | McMaster-Carr

Lower Angular Contact Bearing Retaining Ring

For holding the lower angular contact bearing retaining ring to the bearing housing:

4x Alloy Steel Socket Head Screw, Black-Oxide, M4 x 0.7 mm Thread, 12 mm Long | McMaster-Carr

There are two M4-0.7 tapped holes 9.5mm deep for jacking the ring away from the housing, we used 25mm long screws.

Bearing Housing

Grub screws w/ teflon tape for sealing some water ports (manufacturing process side effect?):

2x Alloy Steel Cone-Point Set Screw, M6 x 1 mm Thread, 8 mm Long | McMaster-Carr

TODO verify the following:

For holding the bearing housing to the main spindle body:

6x Alloy Steel Socket Head Screw, Black-Oxide, M5 x 0.8 mm Thread, 16 mm Long | McMaster-Carr

Upper Angular Contact Bearing Retaining Ring

For holding the upper angular contact bearing retaining ring onto the housing:

4x Alloy Steel Socket Head Screw, Black-Oxide, M5 x 0.8 mm Thread, 12 mm Long | McMaster-Carr

Upper Rotor Bore Cover

For holding a lid over the upper part of the rotor to protect the floating bearings from contamination:

3x Alloy Steel Socket Head Screw, Black-Oxide, M4 x 0.7 mm Thread, 12 mm Long | McMaster-Carr

Spindle Top Cap

For holding the water inlet/electrical inlet cap onto the main spindle body:

6x Alloy Steel Socket Head Screw, Black-Oxide, M5 x 0.8mm Thread, 35mm Long, Partially Threaded | McMaster-Carr

TODO military connector screws?

Online Resources

JGD 125C Spindle Motor 5.5 KW ER25 Stone Water Cooling Cnc Milling Machine Spindle 380v / 220v 4pcs Bearing High Speed|Machine Tool Spindle| - AliExpress