A plank door, a shed door or a barn door is about to go up on black strap hinges with a hand-forged look, or an old strap has bent and needs a match. Acorn's item pages answer the questions that decide the order: where the length is measured, how many hinges carry how much, and which straps only look like hinges.
How Acorn measures a strap hinge: length, width and hinge pad
On the AINBP, RI8BP and RIBBP pages, Acorn gives the length from the tip of the strap to the center of the barrel. Measured that way, the AINBP smooth bean strap is 15-5/8 inches, 1-1/2 inches wide on the hinge side, with a 4 x 2 inch hinge pad. The RI8BP rough heart strap and its half surface version, the RIBBP, are 20-1/2 inches long and 1-9/16 inches wide at the hinge, with the same pad. The heavy duty IHLBP has a 30-3/4 inch strap, 3 inches wide at the hinge, on a 3-3/4 x 6 inch pad.
To match an old hinge, take the same three numbers from it. None of the pages quoted here ties strap length to door width. Acorn's functional strap hinges run from the 9 inch RI5BP to the 36-3/4 inch heavy duty models, with bean, heart and spear ends (AINBP, RI8BP and AI8BP, for example). The AINBP, RI8BP and RIBBP have a removable pin and, per their pages, work on right or left hand doors. Smooth and Rough in the names describe the texture: Acorn calls the RIBBP rough textured steel, meant to look like weathered old iron and steel.
Full surface or half surface strap hinge
In Acorn's description of the RIBBP, a half surface hinge has its strap on the face of the door and its butt end mortised into the door jamb, where it is mostly out of sight once the door is closed. Acorn suggests this type where the door trim leaves no room for a full surface hinge, and the RIBBP page lists interior and exterior doors, sheds, barns and other outbuildings as uses. The full surface version of the same 20-1/2 inch heart strap is the RI8BP, and Acorn's functional list has one more half surface model, the 17 inch RIABP. Our guide to door hinge types compares surface and mortise hinges.
How many strap hinges for a door, and how heavy
Each figure below belongs to the item whose page prints it:
| Acorn item | Length | Load as Acorn states it |
|---|---|---|
| AINBP smooth bean | 15-5/8 in. | 3 hinges, doors up to 175 lbs |
| RI8BP rough heart | 20-1/2 in. | 3 hinges, doors up to 175 lbs |
| RIBBP half surface heart | 20-1/2 in. | 3 hinges, doors up to 175 lbs |
| IHLBP heavy duty bean | 30-3/4 in. | 600 lbs per pair |
| IHJBP heavy duty heart | 30-3/4 in. | 600 lbs per pair |
| ISLBP stainless bean | 30-3/4 in. | 600 lbs per pair |
The heavy duty rating counts a pair, and the same pages add that a pair was tested to 1,000 lbs. For any other size, check that hinge's own page.
Heavy duty strap hinges: steel and stainless steel
Acorn presents its heavy duty strap hinges for garages, barns and gates. The IHLBP bean and the IHJBP heart are made of steel with a matte black finish, 3/8 inch thick, with three knuckles, a removable pin and eleven 1/4 x 2 inch stainless steel lags. In the heavy duty list, each bean and heart size also comes in stainless steel. The ISLBP page repeats the IHLBP's sizes and ratings with one difference: it is made of stainless steel with a matte black finish.
What is a dummy strap?
A dummy strap has the look of a strap hinge but does not hinge anything. Acorn keeps decorative strap hinges, which it also calls dummy hinges, in a list apart from the functional ones and presents them as an accent for any door, garage doors included. The IHCBP and IHQBP descriptions list a strap and its fasteners, with no pin, hinge pad or knuckles.
The 14 inch IHCBP heart dummy strap is made from forged steel with a hand hammered edge and a matte black lacquer finish. The 30 inch IHQBP bean dummy strap is steel, 3 inches wide and 3/8 inch thick, like the IHLBP hinge. The decorative list also holds aluminum straps, and their titles say so.
Garage door strap kits
Acorn builds its garage door kits from the pulls and straps of its other lines, in 4-strap and 6-strap versions of each style. The GAR1A heart kit has two RP2BP heart handles and four RI2BP heart straps, 18-3/4 x 1-9/16 inches. The RI2BP sits in Acorn's decorative strap list, so these straps are decorative rather than working hinges. The GAR1A page gives the kit as steel with a matte black finish. The GAR4A spear kit pairs four 24 x 1-3/4 inch straps with two 7-3/4 x 2 inch handles.
Sonora flat end straps from the Agave line
Acorn also lists decorative straps from Agave Ironworks' hardware line. Its page gives the 12 inch ST017 Sonora matte flat end strap as made from forged iron with Agave's flat black powder coat, 12 x 1-1/2 inches with a 3/8 inch projection. Matte Sonora straps run from 12 to 30 inches (ST017 to ST023).
Of the Acorn pages quoted here, only the ST017 page says forged iron. The RIBBP, IHLBP, IHJBP, IHQBP, IHCBP and GAR1A pages say steel, the ISLBP page stainless steel.
Fitting notes from Acorn's item pages
- AINBP and RI8BP: with the door closed, set the strap in place, trace the holes and predrill. Tighten the screws by hand, not with a power driver, to protect the finish.
- IHCBP: the same steps, with a 1/8 inch bit for hardwood or a 3/32 inch bit for softwood.
- IHLBP, IHJBP and IHQBP: predrill with a 5/32 inch bit and tighten by hand so the paint does not chip. Acorn also asks for clean chrome plated tools, to prevent rust.
- GAR1A and GAR4A: for a new installation, predrill with a 7/64 inch bit in softwood or 1/8 inch in hardwood, and tighten by hand.
These are Acorn's short notes, not a full installation method. More Acorn hardware is on our Acorn brand page. Strap hinges for window shutters are a different family, explained in our shutter hinge guide.
Have the old hinge's measurements and your door's weight at hand when you call. Our customer support team is available Monday - Friday, 8 AM - 4 PM Central Time, at 1-888-800-7789 or [email protected].
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