Fabrication Plans

The schematic MTDC gravel bag pattern on page 9 shows the general layout. Plan dimensions could vary slightly based on fabric used. Fabricate a prototype before mass producing. The steel hoop should be fabricated first.

STEEL HOOP DETAIL

1. Steel bar is 1-1/4" x 45-1/2" x 3/16". 2. From the center point of the bar, measure 6" out on each side and make 90° bends on both. Now round the free ends together and weld. 3. Weld the chain links to the hoop. A carabiner or metal double snap clip can be used to connect the chains to each other. Decker saddles require 9" of chain on each side, while sawbuck saddles require 20" per side.

SEWING INSTRUCTIONS

R = right side of material, and W = wrong side

1. Fold material with wrong sides together, and match 1" side dots with the back side 2" dots and stitch (Figure A). 2. Check to make sure the material will fit snugly around the metal hoop, then remove hoop.

3. False Fell Seam: Fold the 2" side around the 1" side (Figure B). Tuck by folding it again and stitching as shown. The second stitch line must be started from one end to the halfway point. Clip thread and finish stitch line from the other end.

4. The hoop end will be double-folded. To reduce bulk, cut 4-1/2" of false fell seam from the hoop end (Figure C).

5. At the hoop end, fold at the 5-1/2" fold line. 6. Stitch completely around on the 4-1/2"stitch line (Figure D).

7. Cut rectangular holes for hoop chain links. Use a hot-knife if material is Cordura™, and burn through both layers (Figure E). 8. Insert the hoop and pull the chain links up through the holes.

9. Fold fabric around the hoop. Hoop edge should be on the 8-1/2" fold line dots. 10. To attach the hoop inside the bag, stitch close to the fold edge on the inside of the hoop (Figure F).

11. To secure the hoop, stitch over the stitch line created in Step 6, reinforcing it since the machine will not sew completely into the corners.Lock stitches (Figure G).

12. Bottom D-ring: Webbing 1-1/2" x 10". Use 3-point, running 'W' stitch (Figure H). 13. Bottom support: Material 17-1/2" x 2-1/2" with 1" seam tape on all four sides. 14. Attach taped piece on three sides (two long sides and one short side). 15. Insert 1" x 16" steel or aluminum strip. Sew open end shut.

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