Product Line: Mechanical / Gap Frame Presses

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Production Resources, Inc. (PRI) supplies new Stamtec gap frame (C-frame) presses from 22 to 330 tons, Stamtec straight side presses, and Eagle mechanical presses, along with the coil feeding, die protection, tonnage monitoring and guarding to put them into production. PRI's applications engineers help you size the press to the job before you buy.

Gap Frame Presses

Gap frame presses provide open, three‑sided access to the die space, making them ideal for applications that require flexible part handling, quick tooling changes, and unobstructed integration of feeders or secondary operations. Their C‑shaped frame allows operators to load, unload, or manipulate workpieces from multiple directions while still delivering the rigidity and stroke control needed for a wide range of stamping, forming, and assembly tasks. Gap frame presses are widely used for medium‑volume production of brackets, housings, electronic components, and general‑purpose stampings where versatility, accessibility, and efficient floor‑space utilization matter as much as throughput.

Typical PRI use cases: cell‑based stamping operations, hand‑transfer or robotic‑transfer forming, secondary operations such as coining or bending, flexible workcells requiring frequent die changeovers.

Mechanical Presses

Mechanical presses convert rotary motion into a precise linear ram stroke using crank, eccentric, or flywheel mechanisms. They excel at high‑speed blanking, piercing, and progressive stamping where cycle time, repeatability, and slide accuracy determine part quality and throughput. Mechanical presses are the go‑to choice for long production runs of automotive stampings, appliance components, electrical hardware, and other high‑volume parts that require tight dimensional control.

Typical PRI use cases: progressive die stamping lines, high‑speed blanking cells, multi‑station progressive tooling with coil‑feed integration.

Types of Gap Frame and Mechanical Presses

1-Point Gap Frame Presses

What they are: Single-crank C-frame presses. The Stamtec OCP Series (27 to 330 tons) is designed for stamping small parts at high single-stroking rates or in continuous mode, from blanks or coil stock. The GL1 Link Motion Series (88 to 220 tons) is designed for small parts that need deeper or more complex forming. The GHS Series (22 to 66 tons) is Stamtec's high-speed, precision gap frame press, running up to 750 strokes per minute. For fully programmable motion, the iS1 Series is a direct-drive gap frame servo press from 88 to 330 tons.
Typical uses: general stamping, blanking, forming, progressive die work and high-speed single-stroke operations.

2-Point Gap Frame Presses

What they are: C-frame presses with two cranks and a larger die area. The Stamtec G2 Series runs from 121 to 330 tons, with the slide guided by six-point, full-length box-type gibs.
Typical uses: relatively long, narrow parts, and progressive dies that need a longer bed area.

Straight Side Presses

What they are: Presses with columns on both sides of the die, built to hold alignment under high tonnage and off-center loads. PRI supplies Stamtec 1-point and 2-point straight side presses and Eagle SC, SE and SEL Series presses.
Typical uses: larger dies, heavier tonnage, and high-volume progressive and blanking work.

How to Choose the Right Gap Frame Press

1. Tonnage, and where in the stroke you need it. A press delivers its rated tonnage at a set distance above bottom of stroke. Estimate your job with our press tonnage calculator and see press calculations and definitions.
2. Die size and bed area. Most small and medium dies fit a 1-point press; long dies and multi-station progressive dies point to a 2-point press.
3. Stroke length and speed. Blanking favors speed; forming and drawing favor a longer stroke or a link-motion drive.
4. Off-center loading. Progressive dies with uneven station loads call for a 2-point or straight side press.
5. Feeding and automation. Coil feeds, straighteners and part handling affect bed height, feed line and floor space.
6. Protection and controls. Overload protection, tonnage monitoring and die protection inputs keep tooling and the press safe.
7. Guarding. Light curtains and point-of-operation safeguarding to meet OSHA 1910.217.

Send PRI your part print, material and thickness, and production rate, and our applications engineers will recommend the press and the equipment around it. Call (800) 863-3164 or use our Request for Quote form.

Frequently Asked Questions

What is a gap frame press?

A gap frame press, also called a C-frame, OBI, OBS or OBG press, is a mechanical press whose frame is shaped like the letter C and open on the front and both sides. The open throat gives easy access to the die for loading, unloading, feeding and die changes, in a compact footprint.

What is the difference between a gap frame press and a straight side press?

A gap frame press is open on three sides, which makes it easy to access and economical. Under heavy or off-center loads the open C-shape deflects more than a closed frame. A straight side press has columns on both sides of the die, which holds the slide parallel under high tonnage and off-center loads, so it is used for larger dies and heavier work.

What tonnage do gap frame presses come in?

Stamtec gap frame presses run from 22 to 330 tons: the high-speed GHS Series 22 to 66 tons, the 1-point OCP Series 27 to 330 tons, the link motion GL1 Series 88 to 220 tons, the 2-point G2 Series 121 to 330 tons, and the iS1 servo press 88 to 330 tons. Our press tonnage calculator gives a starting estimate for your part.

Do I need a 1-point or a 2-point gap frame press?

Stamtec's 1-point OCP and GL1 Series are designed for stamping small parts. The 2-point G2 Series is designed for relatively long, narrow parts and for progressive dies that need a longer bed area.

What is a link-motion press?

A link motion press slows the slide during the working portion of the stroke. On Stamtec's GL1 Series the slide velocity drops by up to 40 percent there, so the material flows more effectively, while the non-working portion speeds up to keep production rates high. The slower working stroke also reduces die impact, snap-through, noise and vibration, which increases machine and die life.

Can PRI supply the feed, die protection and guarding with the press?

Yes. PRI can supply Stamtec presses on their own or as a complete press line, with coil handling and feeding equipment, tonnage monitoring, light curtains, press mounts and quick die change systems.

Mechanical / Gap Frame Press Products