Rong Fu RF-25 Mill/Drill Specifications & Views
Last updated on Wednesday, June 07, 2023 05:58:30 AM Mountain US Time Zone


Specifications, Belts Drive, Speeds,
Fine Down Feed, Motor, Integral Light, Milling Vises,
Power Feed, Quill Arms,
Machine Mounts

RF-25 Mill DRO & X Y Z axes scales.
RF-25 Mill Tachometer & SFM

Belt Drive
RF_belt_drive.jpg (55878 bytes)
Runs very smoothly & quietly. Multiple pulleys provide
ample torque & no gears to break. Drawbar nut is 17mm.

Original unmodified RF-25 mill configuration. The 4" vise has
been replaced by a 6" Parlec vise, DROs added, & the standard

incandescent light replaced by a high-intensity halogen lamp.
The mill
is at the upper limits of weight & size that I could safely move down

a hill & into my lower-level walkout. 
More books on machining.

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Drilling Capacity 1" (2.54cm)
Face Mill Capacity 2-1/2" (6.3cm)
End Mill Capacity 1/2" (1.3cm)
Swing 15.875" (40cm)
Spindle Nose to Table Max. Distance 15" (38cm)
Spindle Taper R-8
Z - Spindle Stroke 4" (10cm)
Spindle Sleeve Diameter 2.44" (6cm)
Head Swivel 360 deg
Column Diameter 3.625" (9cm)
Overall Height (w/o Stand) 35-1/2" (90cm)
Machine Stand Height 30" (76cm)
Length 36-1/2" (93cm)
Width. 37-1/2" (95cm)
Motor, 110v single phase 1 HP
Spindle Speeds @ 60 Hz 110~ 2580 RPM
Spindle Speeds @ 50 Hz 90 ~ 2150 RPM
Forward & Reverse Switch Standard
 7/16"-20 Drawbar, 2-1/2" Carbide Fly
Cutter/R8-20mm Arbor,
1/2" Chuck
w/R8-J33 Arbor, 2-1/2" Angle Vise
Y - Forward / Backward Table Travel 5.962" (15cm)
 X - Left / Right Table Travel 14.563" (37cm)
Working Area of Table 23"x7-1/2" (58x19cm)
Volume 18.3 cubic ft (0.52 cubic meters)
Noise 80 dB Max
Gross Weight 440 lb (199.6 kg)
Net Weight 374 lb (169.6 kg)

Rong Fu RF-25 mill manual. Specifications of machines
may vary among sellers; values are approximate.

 RF_T_slot_specs.jpg (11910 bytes)
RF-25 mill table slot dimensions. 
24mm = 0
.945", 14mm = 0.551", & 10mm = 0.394".

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RF_motor_reversing_switch.jpg (36536 bytes)
Forward (up), Stop & Reversing (down) switch.

RF_speeds.jpg (50450 bytes)
12 speeds. Easy to change; note &
set two numbered pulley positions.

Fine Down Feed
RF_fine downfeed.jpg (38904 bytes)
The fine down feed housing is held to the mill with
two hex bolts. To add some backlash adjustment

to the fine down feed, the housing was removed,
the two 9mm mounting holes were opened up to about

9.5mm & the bolt heads were turned down a few
thousandths. There was also paint over spray on the

worm gear that was removed. Be sure to re-grease
the worm gear. These relaxed tolerances allowed

additional housing movement to mesh the gears much
closer & thus reducing backlash. All three axes scales
(1 division = 0.001") were verified as accurate.

RF_head.jpg (52682 bytes)
Depth stop & quill lock.

RF_1hp_motor.jpg (35286 bytes)

1 HP, 110VAC, 60 Hz, single-phase,
fully enclosed, externally cooled, motor.

Note, motor locking leaf bolt for belt adjustment &
the two, OEM 19mm (3/4") column locking nuts.
Possibly due to
the OEM bolts not being hardened, they were beginning to strip.

The OEM head-locking cross bolts are a non-standard
size of 1/2-12x7 with 13/16" hex heads which makes it very hard to
find a direct replacement. A standard bolt is 1/2-13 with a smaller,

3/4" hex head which would not properly fit into the cast recess that
prevents turning. The bolt holes were already 9/16" &
did not have to be opened up so I bought hardened,

Grade 8, standard 9/16-12x7 bolts from Bolt Depot.
This size has the requisite 13/16" hex head & fit

through the holes but the bolt touched the mill's column.
I lathed the center area down to 1/2" as
well as relieving the area under the head.
The bolts fit perfectly & are now all hardened,

bolt/washer/nut assemblies. A 7/8", 12-point deep socket,
used with a long-handled 3/8" drive

ratchet work nicely. A 12-point socket engages the nut
quicker (using less wrench movement).

The best alignment is achieved by tightening the top
bolt first & then going back & forth a few times.

Task Light

Halogen task light.

I used several electrical box covers to
give the magnet a good base to grip.








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Integral Light

Installed a vibration-resistant 60W light in
the mill head's internal cavity. The large upper plastic
housing holes allow heat dissipation via convection.

The upper bracket is shown. A porcelain socket &
rotary switch were used. The AC cord is held by a cable tie down.
This is similar in function to my OEM light in the
Jet floor drill press.

The bulb sticks out to give a better light
dispersion angle & good accessibility for changing.


Cutting with the halogen light
on but the built-in lamp off.

Cutting with both the
halogen & built-in lamps on.

Milling Vises

Parlec PSW-6900. The upgraded vise is several
orders of magnitude improvement over the 4" model.

Width sizes available:
 3" (76mm), 4" (102mm), 5" (127mm), 6" (153mm)










2 styles available, 1-pk or 2-pk:
3-5/8" x 3/4" & 5-1/2" x 1-1/8"




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RF_milling_vise.jpg (46776 bytes)
First selected a Kurt-style 4" milling vise (37 lb.)
Used hardened bolts & washers with standard T-nuts.
Parlec 6" vise now being used on the RF-25.

Swivel base for the 4" mill vise. Remove to increase
Z distance & overall rigidity. Used only as needed.

Power Feed
RF_power_feed_2.jpg (40392 bytes)
Variable speed power table feed has high
torque throughout its range, works very well.

Clamps onto table end. An integrated travel-limit
switch is mounted on the front edge of the table.

RF_power_feed.jpg (43391 bytes)
Left/Right direction lever, variable-speed dial &
momentary extra high-speed (yellow) button.

Gear attached where original handle was located
(black plastic gear cover removed for illustration).

Power table feed operation manual.

CAUTION: Do not change power feed directions
suddenly, especially at high speeds. Move lever to
the center, neutral position & wait until motor stops.

The yellow gear cover removed.
Use graphite-based grease not silicon type.

Bottom view showing the motor engaging the
X-axis gear that replaced the left OEM mill handle.

RF_power_feed_limit_switch.jpg (46191 bytes)
Integrated table travel-limit switch.

Quill Arms

Removed all of the quill levers so they do not
contact the piece when working close to the vise.

This configuration allows much better access
to the
two column locks, belt tension lock, & DRO.
I made & installed 1/2-12 threaded aluminum
plugs to give it a finished look & keep the chips out.

 I like the extra control afforded by the
fine down feed & have no need for the levers.

Machine Mounts
RF_stand_machine_foot.jpg (29544 bytes)
Vibration-absorbing machine mounts
supporting (optional) Rong Fu cabinet.












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Specifications, Belts Drive, Speeds,
Fine Down Feed, Motor, Integral Light, Milling Vises,
Power Feed, Quill Arms,
Machine Mounts