Aluminum Tri-Adj 1-Ton Gantry Crane, 14ft 1in – 21ft 7in Ht, 12ft Span (A2T21-A12)

Model A2T21-A12

1-Ton Tri-Adjustable Gantry Crane
14′ 1″ – 21′ 7″ High, 12′ Span

Aluminum Construction
✓ Adjustable Height (C), Span(B), and Caster Frame Spread (E)
✓ 1 Ton (2,000 pound) capacity (A)
✓ 5′ 7″ Clear Span (D)
✓ 7′ 4″ – 12′ 10″ Caster Frame Spread (E)
✓ 11″ Leg Clearance (F)
✓ 8″ Caster Diameter (G)
✓ 8″ I-Beam Depth (H)
✓ 542 Pounds Net Weight

Designed and manufactured in the United States
Completely portable
Easy to assemble, disassemble, transport, and store
Lightweight yet strong
Designed to roll under load

Most orders ship in 3 to 5 days.

Product Details

Model A2T21-A12

Key Features

Durable, Stable, Adjustable, and Portable

Our most popular product line is the lightweight aluminum tri-adjustable 1/2 to 3-ton gantry crane. The aluminum design makes these cranes an ideal combination of high lifting and reduced weight. Made with high-quality heavy-gauge aluminum tubing, our 1/2 to 3-ton Tri-Adjustable gantry cranes are designed to roll under load. They have an adjustable height (C), span (B), and caster frame spread (E).

  • The Tri-Adjustable is built using our patented pinned-joint design resulting in a longer-lasting, better-fitting, more flexible crane that is quick and easy to assemble and disassemble.
  • Exclusive Wallace I-beam support system aligns off-center loads to avoid crane and trolley distortion. Support system slides along the I-beam enabling leg spacing adjustments and cantilever configurations.
  • Casters are equipped with a 4-position swivel lock. When locked 90 degrees with each other, they position the crane more firmly than a brake.
  • Adjustable legs permit crane height adjustments in 6″ increments using spring-loaded bolts. You can raise the height of your crane so it goes over materials and equipment, lower it under low ceilings and doorways, or set legs at different heights when floors or terrains are uneven. It’s ideal for truck loading or from a dock to a floor or ground level to a mezzanine.
  • Adjustable span allows for inboard or outboard bracing and a cantilever configuration overhang of up to 25% of the I-beam length.
  • Adjustable caster frame spread (E) enables rolling through narrow aisles or doorways and prevents having to disassemble and reassemble your crane. Safety cables inside the caster frame tubes prevent overspreading while adjustments are underway. Casters are equipped with 4-position swivel locks to position the crane more firmly than a brake.
  • Tri-adjustables can be wheeled around to serve more than one workstation or workplace. Lock “lead” casters and unlock trailing casters to easily move and steer crane. An optional Kart Kit transforms your disassembled gantry crane into a cart, allowing easy transportation and storage.

Model A2T21-A12

Dimensional Drawing

Aluminum Tri-Adj 1-Ton Gantry Crane, 14ft 1in – 21ft 7in Ht, 12ft Span (A2T21-A12) Dimensional Diagram

Print / download the A2T21-A12 dimensional drawing (PDF).

View I-Beam Flange Width Chart for Wallace Gantries.

Model A2T21-A12

Parts List

1 MAIN LEG BRACKET 1553-0000 4
2 SUPPORT PIN 11/16 DIA. X 4 9/16 LG. 5017-0004 4
3 SPACER BAR 32 1/2 LG. 1744-0007 2
4 COTTER PIN 1/4 X 1 1/4 LG. 60-0070 8
5 HEX. NUT 3/8-24NC 54-0100 4
6 SOC. SET SCREW 3/8-24NF X 1 3/4 LG. 63-0110 4
7 SOC. SET SCREW 3/8-24NF X 1 LG. 63-0100 4
8 LEG BRACE BRACKET 1761-0000 4
9 SUPPORT PIN 11/16 DIA. X 4 1/8 LG. 2853-0000 4
10 MAIN LEG SWIVEL PIN 1559-0000 4
11 LEG BRACE SWIVEL PIN 1563-0000 4
12 HEX. HD. BOLT 3/4-10NC X 2 1/2 LG. 51-0480 4
13 TROLLEY STOP ANGLE 3464-0000 4
14 KEY RING 2 1/4 OD. 82-0030 10
15 CAUTION TAG NO. 399 1969-RING 12
16 LOCK WASHER INT. TOOTH 3/4 58-0040 4
17 NEX. NUT 3/4-10NC 54-0040 4
18 I BEAM AL. 8″ X 12′ LG. 751-0120 1
19 LEG BRACE ASSEMBLY 1542-0120 4
20 MAIN LEG ASSEMBLY 1650-0121 4
21 UPPER MAIN LEG 1651-0120 4
22 ROLL PIN 5/32 X 3/4 LG. 61-0300 4
23 LOAD PIN 3016-0000 4
24 EXTENSION SPRING 1017-0000 8
25 LOWER MAIN LEG 1652-0120 4
28 HEX. HD. BOLT 1/2-13NC X 4 LG. 51-0460 4
29 SAFETY CABLE ASS’Y 155″ LG. 1967-0030 2
35 LOCK WASHER INT. TOOTH 1/2 58-0020 4
36 HEX. NUT 1/2-13NC 54-0050 4
37 HEX. HD. BOLT 3/8-16NC X 1 1/2 LG. 51-0190 16
38 LOCK WASHER INT. TOOTH 3/8 58-0060 16
39 HEX. NUT 3/8-16NC 54-0060 16
40 CASTER WHEEL 8″ DIA. 47-0010 4

Note: There are alternate v-groove casters available for this crane.

Print / download a copy of the A2T21-A12 parts list  (PDF).

Model A2T21-A12

Parts Location Diagrams

Round-Tube Tri-Adjustable I-Beam Assembly Parts Location Diagram | Wallace Cranes

Round-Tube Tri-Adjustable I-Beam Assembly Parts Location Diagram

Round-Tube Tri-Adjustable Caster Frame Assembly Parts Location Diagram | Wallace Cranes

Round-Tube Tri-Adjustable Caster Frame Assembly Parts Location

Print / download a copy of crane parts location diagrams (PDF).

Model A2T21-A12

Optional Accessories

Optional Kart Kit for Tri-Adjustable Cranes |

Kart Kit for Tri-Adjustable Gantry Cranes

Available accessories include manual and electric trolleys and hoists, jack kits for frequent crane height adjustments, kart kits for transforming your disassembled crane into a cart which allows for easy transport and storage, and festooning kits to keep hoist, trolley, and power drive system cords up and out of the way.

Options for track mounting with V-groove casters and motorizing cranes are also available.

Model A2T21-A12

Assembly and Disassembly Instructions


  1. Read and understand instructions before using this gantry.
  2. Inspect gantry thoroughly before using. See the Tri-Adjustable Operating, Adjustment, and Inspection Instructions (Form 379) for damaged or missing parts.
  3. Do not lift more than rated capacity.
  4. Center hoist over the load.
  5. Do not allow the load to swing or roll against any supporting members.
  6. When moving the gantry under load, push on the gantry, not the load. Be certain that the rolling surface is hard, level, clean, and smooth.
  7. Do not move the gantry over 50 feet per minute (1/2 m.p.h.).
  8. Not to be used for lifting or supporting humans.

Before You Begin

  1. Place parts on a flat surface, preferably on cardboard to keep small parts clean and organized.
  2. Select a clear area to assemble the crane. The work envelope should extend five feet beyond twice the leg length (when flat) and the length of the I-beam.
  3. This clear area should be serviced by two overhead hoists or an alternate as shown below as well as in Form 379. This will allow you to raise the I-beam and leg assemblies when required.
    Ways To Support Assembly of Gantry Crane | Wallace Cranes

  4. Select tools for fastening the nuts and bolts.
  5. You will also need C-clamps to hold the trolley in place while the crane is assembled.

Print / download a PDF of detailed, step-by-step Tri-Adjustable Gantry Crane Round-Tube Assembly Instructions (Form 429).

Model A2T21-A12

Safety Tag and Label Locations

Safety Tag Location

The following sketch shows the location of required safety tags on Wallace Tri-Adjustable Gantry Cranes. All locking pins or pins with a quick release must have a corresponding Tag 1969. Following the schematic below is a complete listing of all text found on all Labels and Tags on the Crane.

Tri-Adjustable Round-Tube Safety Tag and Label Locations

Print / download a PDF of the Tri-Adjustable Round-Tube Safety Tag and Label Locations Diagram.

Model A2T21-A12

Inspection Checklist (Form 504)

Instructions include:

  • What to check for.
  • How often to check.
  • Frequent Inspection Checklist.
  • Periodic Inspection Checklist.

View detailed Gantry Crane Inspection Checklist (Form 504).

Print / download a PDF copy of the checklist.

If you have questions or need assistance, please contact us.


Please note this checklist was derived from company proprietary materials and (3) source documents including ANSI B30.17CMAA Specification #74 Revised 1987, and OSHA 1910.179. As excerpts, the short form Wallace documents are intended to serve as general guidelines and are not to be considered the sole source when performing routine maintenance and inspection tasks.

Model A2T21-A12

Operating, Adjustment, and Inspection Instructions (Form 379)

Instructions include:

  • Assembly and Safety Instructions
    • Daily inspection
    • Positioning of Crane to Handle Loads
    • Positioning of Casters
  • Adjustment Instructions
    • Height Adjustment Procedure
    • Caster Frame Adjustment Procedure
    • Cantilever Configuration / Adjustment
  • Wallace Built-In Safety Features
  • Caution Areas
  • Tri-Adjustable Visual Checkpoints
  • General Safety Instructions for Crane Adjustments
  • Methods of Supporting the Crane for Assembly

View detailed Tri-Adjustable Operating, Adjustment, and Inspection Instructions (Form 379).

Print / download a PDF copy of the instructions.

Model A2T21-A12

Cantilever Instructions

Gantry Crane Cantilever Charts

Cantilever Chart

Gantry Model Number: A2T21-A12
I-Beam: A 8″ x 6.4#/’ x 12′
I-Beam Length (Overall Span): 144 Inches
Maximum Cantilever Distance (A): 36 Inches
Gantry Rated Capacity: 2000 lbs.
Maximum Cantilevered Load (B): 1200 lbs.
Gantry Weight: 554 lbs.
I-Beam Weight: 76.8 lbs.

Proper Cantilever Procedures

Required counterweight should not be supported by gantry caster frame.

Load and trolley should be able to freely traverse the I-beam through the main legs and brace legs of the gantry.

Required Counterweight at (C)



1 0 0 0 0 0 0
2 0 0 0 50 130 210
3 0 2 135 269 402 535

Print / download a PDF copy of these A2T21-A12 cantilever instructions.

Model A2T21-A12

Warranty and Disclaimer

Wallace product warranty and errors and omissions disclaimers can be found below.

They are also in the About section of this website and on the main 1/2 – 3 ton aluminum Tri-Adjustable gantry crane page.

Model A2T21-A12

Engineering Specification

Gantry end frames shall be of aluminum alloy round-tube construction manufactured to Wallace Cranes standards including, but not limited to, the following:

  • Gantry shall be adjustable in height and have main leg center castings for brace leg attachment to main support legs.
  • Gantry shall be adjustable in span so that operators may adjust the crane to an inboard braced, outboard braced, or a combination of the two or approved cantilevered configuration.
  • Gantry shall be adjustable in caster frame spread and have aluminum castings for attachment of casters.
  • The aluminum alloy I-beam shall be American Standard and have a design deflection of no greater than l/450th of the span. The I-beam shall also be free-swinging and self-aligning to lift off-center loads as approved.
  • The telescoping legs shall be adjustable in 6” increments and also be equipped with malleable iron safety stops for everyday use as well as when adjusting height.
  • Spread adjustment on the caster frame shall be in 6” increments. Over spreading of the caster frame adjustment shall be prevented by means of an internal steel safety cable.
  • The main leg center casting shall have spring-loaded pearlitic grade load-adjusting pins for adjusting/maintaining height adjustment of crane as well as attachment of brace legs.
  • Gantry shall be equipped with four (or eight, depending on the model), 360 degree rotating, non-marking phenolic resin casters with 4-position swivel locks, at 90 degrees, to provide easy steering of crane by locking “lead” casters only, or to allow positioning of crane more firmly than a brake by locking all four (or eight depending on the model), casters 90 degrees to each other. Casters shall be 6” or 8” diameter as determined by capacity, height, and span of crane.
  • The model number to be provided shall be tested in accordance with Wallace Cranes specifications (A specific unit shipped is not tested; unless a Certificate of Test is ordered [additional charge applies]).
  • Gantry is manufactured in accordance with our interpretation of ANSI B30.17 and U.S. OSHA, (Section 1910.179, revised January 1976), regulations at the time of manufacture.

Print / download a PDF version of the specification.

Model A2T21-A12

Photo Gallery

Wallace Tri-Adjustable gantry cranes have a wide variety of commercial and industrial applications, both indoors and out. Images (below) provide a sampling of different applications of our steel (red) and aluminum (silver) Tri-Adjustable gantry cranes.

Want help?

We have experts on hand to answer all your questions (1-800-553-5438).

Related Products

Wallace offers a lighter-weight alternative to the Tri-Adjustable in the form of our Thrifty gantry crane. Thrifties do not have brace legs under the i-beam. They come with steel or aluminum construction, fixed or adjustable height, and weigh as little as 135 pounds.

Thrifty Crane Dimensional Sketch

Thrifty Gantry Sketch