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Semi-Automatic | Pneumatic Underpinner

Product Number: 178690012CE

The U-400 has been designed for ease of operation and is particularly well suited for joining large frames up to 5 ½” (140mm) in width.

Supplied with a tilting floor stand, the machine can be operated from the front or back and has a single stage pneumatic foot pedal that activates the Horizontal Clamp, securing moulding during the joining process.

After the framer sets the two position stops for measuring the max distance between strokes, a dual function hand lever is then used to position and actuate both the Vertical Mould Holding Clamp and the V-Nail driver inserting V-Nails anywhere along the pre-set stroke distance. 

A key operating feature for the U-400 allows the operator to quickly change V-Nail mm size using an interchangeable metal magazine channel. Operator easily accesses the interchangeable channel from the rear of the machine to load the appropriate V-Nail size. This feature eliminates the added purchased cost of plastic nail cartridges.

Former Model Reference - Alfamacchine – M144

Purchase Package
  U-400 Purchase Package
(1) “Multi-Sized” Nail Head
(1) 7mm Channel Magazine
(1) 10mm Channel Magazine
(1) 12mm Channel Magazine
(1) Single Vertical Positive Placement Clamp
(1) Single Metal Pressure Plate
(1) Magnetic Base for Clamping System
(1) Blue Rubber Pad (SW)
(1) Yellow Rubber Pad (SW)
(1) Black Rubber Pad (SW)
(1) Round Pressure Pad - Felt
(1) Adjustable Fence - 2 Knobs
(1) Front Horizontal Clamp
(1) 4mm Allen Wrench
(1) 5mm Allen wrench
(1) 6mm Allen wrench
(4) Machine base levelers
(1) Floor Stand
(1) Machine Manual
Power Requirements

Compressed Air 4NI at 5 Bar
CE Compliant

Sales & Technical Documents

U400  1.png

U-400 Alfa Sellsheet 1-9-15.jpg

Instruction Manual

- Italian Version

 U-400 Literature 

- Italian Version
- Spanish Version
- French Version

- German Version


Accessories & Replacement Items


Extension Wings

P/N Description
M2200001 Extension Wings Kit



Replacement Nail Heads

P/N Description
394950570 "Multi-Sized" Nail Head
394950010  Nail Head - 3mm
394950060  Nail Head - 5mm
394950020  Nail Head - 7mm
394950040  Nail Head - 10mm
394950030  Nail Head -12 mm
394950050  Nail Head - 15 mm


Replacment Clamping Pads

P/N Description
397100003 Blue Replacement Rubber Pad (recommended for SW)
397100002 Yellow Replacement Rubber Pad (recommended for MW) 
397100001 Black Replacement Rubber Pad (recommended for HW) 



P/N Description
244120130 Magnetic Base for Clamp Assembly
242230300 Single Metal Pressure Plate
397100005 Magnetic - Single Metal Pressure Plate
397100003 Blue Replacement Rubber Pad (recommended for SW)
397100002 Yellow Replacement Rubber Pad (recommended for MW) 
397100001 Black Replacement Rubber Pad (recommended for HW) 
242230010 Round Pressure Pad, Felt
242230040 Round Pressure Pad, Vulkolan
M30100059 5mm Channel Magazine
M30100058 7mm Channel Magazine
M30100057 10mm Channel Magazine
M30100056 12mm Channel Magazine
M30100055  15mm Channel Magazine
M29100004 Fixed Fence - 90°


Dual function
hand lever actuator

Unique Performance Features


  • Handles up to 5 ½ ” (140mm) wide moulding – Unique competitive advantage over other industry frame joiners
  • Designed with “interchangeable channel magazines” allowing operator to quickly change V-Nail sizes
  • Operator controlled arm for left or right operations – allows framer to accurately position the Nail Head for inserting or stacking V-Nails anywhere along the frame joint
  • Uses both a vertical and horizontal clamping method
  • Adjustable working table height for operator comfort
  • Easy table tilt adjustment
  • Join either from back or front of machine        

Frame Joining Capabilities

Moulding Width
(min to max)

Moulding Height
(min to max)

Max Distance
Between V-Nails

¼” up to 5 ½”
(6-140 mm)

¼” up to 3 ¼”
(6-80 mm)

7 7/8”
(200 mm)

Pre-set V-Nail
Position Stops

V-Nail Sizes

V-Nail Channel


5, 7,10,12,15 mm

220 V-Nails/channel

Machine Dimensions & Weight

Length: 600mm (23 3/4")
Width: 640mm (25 ¼”)
Height: 1350mm (53")
Weight: 90 kg (198lbs.)

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