Professional Frame
Joining Machines

Experience precision and reliability with our Italian­ manufactured underpinners. Built for professional frame makers and woodworkers who demand excellence in every join.

Order Now

2 Year

Warranty*

10% Off

Next Order of V-nails with Underpinner Purchase

U400 underpinner in use
U400 underpinner in use

Professional Frame
Joining Machines

Experience precision and reliability with our Italian­ manufactured underpinners. Built for professional frame makers and woodworkers who demand excellence in every join.

Order Now

2 Year

Warranty*

10% Off

Next Order of V-nails with Underpinner Purchase

UnderpinnerQuality

Italian Craftmanship

Premium Quality machines manufactured
in Italy

Warranty

2-Year Warranty

*Manufacturer Warranty
2 years on mechanical,
1 year on pneumatics

Below

Priced Below MSRP

Save money with
AMP Underpinners
from Piel Associates

UnderpinnerQuality

Italian Craftmanship

Premium Quality machines manufactured
in Italy

Warranty

2-Year Warranty

*Manufacturer Warranty
2 years on mechanical, 1 year on pneumatics

Below

Priced Below MSRP

Save money with AMP
Underpinners from Piel Associates

“The ease of use and quick adjustment settings on these underpinners have allowed production to increase efficiency and shorten change over times.”

Mark Vore
Production Manager, Nickell Moulding

“Piel takes very good care of us!
They are a great partner
and we appreciate all
of their help and attention.

J. Miller
Google Review

Quality & Service:
AMP Underpinners from Piel Associates

  • 10% off your next order of V-nails with underpinner purchase
  • Quality machines manufactured in Italy
  • Priced below MSRP
  •  2-year manufacturer warranty on mechanical;
    1 year on pneumatics
  • Genuine AMP parts and accessories in stock or available
  • Tech support from trained AMP technicians
  • Free consultation to choose the right model for your needs
  • Accept all major credit cards

AMP U-Series Underpinners

AMP’s U-Series Product Line offers comprehensive solutions for miter joining, from manual entry-­level equipment to fully automatic, multi-channel units. Perfect for picture & mirror frames, canvas stretcher bars, window & door trim, and exterior moulding trim. The machines are commonly known as Underpinners, Joining Machinery, or Backnailers, depending on the industry sector.

U200

U200 underpinner in use
  • Free Standing
  • Ideal for retail framing shops
  • Foot pedal actuated for V-nail insertion
  • Light production usage
Request Quote

Purchase this model and get:

  • 10% Off Your Next Order of V-Nails

Starting at $2,049.00

U200P

U20P
  • Bench top model
  • Perfect for custom and home business frame shops
  • Operates with pneumatic air, no electrical hook up
Request Quote

Purchase this model and get:

  • 10% Off Your Next Order of V-Nails

Starting at $2,669.00

U300

U300FrameinMachineSiloFinal
  • Semi-automatic, bench top or free standing
  • Flexible joining for multiple custom sized frames
  • Pneumatic foot actuated for V-nail insertion
  • Low Production Usage
Request Quote

Purchase this model and get:

  • 10% Off Your Next Order of V-Nails
  • 10% Off a Wing Kit, Stand and Accessories

Starting at $3,739.00

U300P

U300PBack ApplctionPicFrame
  • Semi-automatic, bench top or free standing
  • Production joining with speed and repeatability
  • Up to 200 joined frames per hour
Request Quote

Purchase this model and get:

  • 10% Off Your Next Order of V-Nails
  • 10% Off a Wing Kit, Stand and Accessories

Starting at $5,959.00

U300P FrntImageApplicationV

U400

U400 MainImage
  • Semi-automatic, bench top or free standing
  • Suited for joining large frames up to 5½” wide
  • Dual hand lever for V-nail positioning
  • Low production Usage
Request Quote

Purchase this model and get:

  • 10% Off Your Next Order of V-Nails
  • 10% Off a Wing Kit and Accessories
  • PLUS a Free 15 mm Channel Magazine

Starting at $7,599.00

U400 underpinner in use

U500

U500Image
  • Production Joining
  • Single sized v-nail for high production
  • Memory programmed frame profile recall
  • Up to 300 joined frames per hour
Request Quote

Purchase this model and get:

  • 10% Off Your Next Order of V-Nails
  • 10% Off a Wing Kit and Accessories
  • PLUS a Free 15mm Nail Head

Starting at $18,999.00

U500 Multi-Level

  • Production framing
  • Multi-height v-nail insertion
  • All U500 features included
  • Advanced profile programming
Request Quote

Purchase this model and get:

  • 10% Off Your Next Order of V-Nails
  • 10% Off a Wing Kit and Accessories
  • PLUS a Free 15mm Nail Head

Starting at $22,229.00

U600

U400 MainImage
  • Production Joining
  • Multiple sized fasteners capability
  • Memory programmed profile recall
  • Up to 300 joined frames per hour
Request Quote

Purchase this model and get:

  • 10% Off Your Next Order of V-Nails
  • 10% Off a Wing Kit and Accessories

Starting at $25,749.00

AMP U-Series Underpinners

AMP’s U-Series Product Line offers comprehensive solutions for miter joining, from manual entry-­level equipment to fully automatic, multi-channel units. Perfect for picture & mirror frames, canvas stretcher bars, window & door trim, and exterior moulding trim. The machines are commonly known as Underpinners, Joining Machinery, or Backnailers, depending on the industry sector.

U200

U200 underpinner in use
  • Free Standing
  • Ideal for retail framing shops
  • Foot pedal actuated for V-nail insertion
  • Light production usage
Request Quote

Purchase this model and get:

  • 10% Off Your Next Order of V-Nails

Starting at $2,049.00

U200P

U20P
  • Bench top model
  • Perfect for custom and home business frame shops
  • Operates with pneumatic air, no electrical hook up
Request Quote

Purchase this model and get:

  • 10% Off Your Next Order of V-Nails

Starting at $2,669.00

U300

U300FrameinMachineSiloFinal
  • Semi-automatic, bench top or free standing
  • Flexible joining for multiple custom sized frames
  • Pneumatic foot actuated for V-nail insertion
  • Low Production Usage
Request Quote

Purchase this model and get:

  • 10% Off Your Next Order of V-Nails
  • 10% Off a Wing Kit, Stand and Accessories

Starting at $3,739.00

U300P

U300PBack ApplctionPicFrame
  • Semi-automatic, bench top or free standing
  • Production joining with speed and repeatability
  • Up to 200 joined frames per hour
Request Quote

Purchase this model and get:

  • 10% Off Your Next Order of V-Nails
  • 10% Off a Wing Kit, Stand and Accessories

Starting at $5,959.00

U300P FrntImageApplicationV

U400

U400 MainImage
  • Semi-automatic, bench top or free standing
  • Suited for joining large frames up to 5½” wide
  • Dual hand lever for V-nail positioning
  • Low production Usage
Request Quote

Purchase this model and get:

  • 10% Off Your Next Order of V-Nails
  • 10% Off a Wing Kit and Accessories
  • PLUS a Free 15 mm Channel Magazine

Starting at $7,599.00

U400 underpinner in use

U500

U500Image
  • Production Joining
  • Single sized v-nail for high production
  • Memory programmed frame profile recall
  • Up to 300 joined frames per hour
Request Quote

Purchase this model and get:

  • 10% Off Your Next Order of V-Nails
  • 10% Off a Wing Kit and Accessories
  • PLUS a Free 15mm Nail Head

Starting at $18,999.00

U500 Multi-Level

  • Production framing
  • Multi-height v-nail insertion
  • All U500 features included
  • Advanced profile programming
Request Quote

Purchase this model and get:

  • 10% Off Your Next Order of V-Nails
  • 10% Off a Wing Kit and Accessories
  • PLUS a Free 15mm Nail Head

Starting at $22,229.00

U600

U400 MainImage
  • Production Joining
  • Multiple sized fasteners capability
  • Memory programmed profile recall
  • Up to 300 joined frames per hour
Request Quote

Purchase this model and get:

  • 10% Off Your Next Order of V-Nails
  • 10% Off a Wing Kit and Accessories

Starting at $25,749.00

AMP Joiners Comparison Chart

Table091825 rev
Download Chart

Also available:

AMP extension wings, stands, fences, clamping pad systems, and replacement parts.

Parts
04-020Single Metal Pressure Plate
04-022Double Metal Pressure Plate
04-023Magnetic Single Metal Pressure Plate
04-024Black Rubber Pad for Hardwoods
04-025Yellow Rubber Pad for Medium woods
04-026Blue Rubber Pad for Soft woods
04-0955 mm Nail Head
04-0917 mm Nail Head
04-09210 mm Nail Head
04-09312 mm Nail Head
04-09415 mm Nail Head
Rubber Pad
View Clamping system