MIL-C-104C_Wood_Crates.pdf

I INCH-POUND I

1. SCOPE

MIL- c - 104c 30 March 1992

SUPERSEDING

29 January 1980

MIL-C-104B

MILITARY SPECIFICATION

CRATES, WOOD: LUMBER AND PLYGJOOD

SHEATHED, NAILED, AND BOLTED

This specification is approved for use by all Departments and Agencies of the Department of Defense.

1.1 Scope. This specification covers requirements for two types and two classes of sheathed crates each of which may have two styles of bases. The crates are designed for net loads not exceeding 30,000 pounds (lb) and to withstand the most severe overseas shipping and storage conditions.

1 . 2 Classification. Crates shall be of the following types, classes, and styles, as specified (see 6 . 2 ) ; these crates are available in fire retardant types, classes, and styles, when specified (see 3 . 8 and 6 . 2 ) :

Type I - Nailed Type II - Bolted Class 1 - Lumber sheathed Class 2 - Plywood sheathed Style a - Skid base Style b - Sill base

2. APPLICABLE DOCUMENTS

2 . 1 Government documents.

2 . 1 . 1 SDecifications. standards, and handbooks. The following specifications, standards, and handbooks form a part of this document to the extent specified herein. Unless otherwise specified, the issues of these

[Beneficial comments (recommendations, additions, deletions) and any pertinent1 ldata which may be of use in improving this document should be addressed to: I ICommanding Officer (Code 156) , Naval Construction Battalion Center, Port I IHueneme, CA 93943-5000, by using the self-addressed Standardization I IDocument Improvement Proposal (DD Form 1426) appearing at the end of this I 1 1 I

AMSC N/A FSC 8115

DISTRIBUTION STATEMENT A. Approved for public release; distribution is unlimited.

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MIL-C-104C 8 3 9 9999906 0533766 T M I

MIL-C-104C

documents are those listed in the issue of the Department of Defense Index of Specifications and Standards (DODISS) and supplement thereto, cited in the solicitation (see 6.2).

SPECIFICATIONS

FEDERAL

FF-B-561

FF-B-584

FF-N-105

FF-N-836

FF-W-92

A-A-55057

S S -R- 501

PPP-B-1055

MILITARY

MIL-L-19140

STANDARDS

MILITARY

MIL-STD-105

MIL-STD-129

MIL-STD-731

- Bolt, (Screw), Lag.

- Bolts, Square Neck and Tee Head.

- Nail, Brads, Staples and Spikes, Wire, Cut and

- Nut, Square, Hexagon, Cap, Slotted, Castle

- Washer, Flat (Plain).

- Panels, Woodflood Based: Construction and

- Roofing Felt, Asphalt Prepared, Smooth Surfaced.

- Barrier Material, Waterproof, Flexible.

Wrought.

Knurled, Welding and Single Ball Seat

Decorative.

- Lumber and Plywood, Fire Retardant Treated.

- Sampling Procedures and Tables for Inspection by

- Marking for Shipment and Storage.'\,,

- Quality of Wood Members for Containers and Pallets.

Attributes.

(Unless otherwise indicated, copies of federal and military specifications, standards, and handbooks are available from Standardization Documents Order Desk, Bldg. 4D, 700 Robbins Avenue, Philadelphia, PA 19111-5094.)

2.2 Non-Government Dublications. The following document(s) form a part of this document to the extent specified herein, Unless otherwise specified, the issues of the documents which are DoD adopted are those listed in the issue of the DODISS cited in the solicitation. Unless otherwise specified, the issues of the documents not listed in the DODISS are the issues of the docdents which are current on the date of the solicitation (see 6.2).

AMERICAN SOCIETY FOR TESTING AND MATERIALS (ASTM)

ASTM D 4442 - Direct Moisture Content Measurement of 'Wood and Wood-Base ASTM D 3950 - Strapping, Plastic (and Seals).

ASTM D 3951 - Commercial Packaging.

ASTM D 3953 - Strapping, Flat Steel and Seals.

Materials, Standard Test Methods for

(Application for copies should be addressed to the American Society for Testing and Materials, 1916 Race Street, Philadelphia, PA 19103.)

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MIL-C-104C 81 9999906 0511767 II =

MIL- C - 104C

AMERICAN NATIONAL STANDARDS INSTITUTE, INC. (ANSI)

ANSI/HPMA HP - Standard Specification for Hardwood and Decorative Plywood.

(Application for copies should be addressed to the Hardwood Plywood Manufacturers Association, 1825 Michael Faraday Drive, P.O. Box 2789, Reston, VA 22090-2789.)

U.S. DEPARTMENT OF COMMERCE

Product Standard PS 1 - Softwood Plywood, Construction and Industrial.

PS 5 1 - Hardwood and Decorative Plywood, (Application for copies should be addressed to the Superintendent of Documents, U.S. Government Printing Office, Washington, DC 20402.)

(Non-Government standards and other publications are normally available from the organizations that prepare or distribute the documents. These documents also may be available in or through libraries or other informational services.)

2.3 Order of precedence. In the event of a conflict between the text of this document and the references cited herein (except for associated detail specifications, specification sheets or MS standards), the text of this document takes precedence. Nothing in this document, however, supersedes applicable laws and regulations unless a specific exemption has been obtained.

3. REQUIREMENTS

3 . 1 Description. The various types, classes, and styles or crates shall be as specified herein and as shown in figures 1 through 3 3 .

3 . 2 First article (preproduction model). When specified (see 6 . 2 ) , the contractor shall furnish one complete crate for examination within the time frame specified (see 6 . 2 ) , to prove that his production methods will produce crates that comply with the requirements of this specification. Examination shall be as specified in Section 4 and shall be subject to surveillance and approval by the Government (see 6.3) .

3 . 3 General Requirements.

3 . 3 . 1 Loading of crates. When crates are furnished as filled containers, the extent of disassembly of the contents, and the anchoring, blocking and bracing, and application of lifting straps shall be in accordance with the appendix to this specification.

3 .3 .2 Weight - limitations. The gross weight of crates shall not exceed 20,000 lb, whenever possible. When this limitation is not practical, gross weight of crates with skid type bases (style a) may go to 30,000 lb.

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M I L - C - L O 4 C A L 999790b 05117b8 3

3.3.3 Dimension limitations. The exterior dimensions of the crate shall not exceed the following limitations, unless specified (see 6.2), for overseas shipment for which dimensions of the International Loading Gauge shall apply, figure 39.

Length - 30 feet Width - 9 feet Height - 10 feet

3.3.4 Interior clearance, A clearance of not less than 1 inch shall be allowed between the item and the closest member of the sides, ends, and top of the crate. Fragile items or items within floating bag barriers shall be protected with clearances of not less than 2 inches. Additional clearances may be provided for shock mounted items. Protruding parts at the top may be allowed to extend between joists; spacing of joists may be adjusted slightly to accommodate projections.

3.3.5 Material. Material shall be as specified herein. Materials not specified shall be selected by the contractor and shall be subject to all provisions of this specification (see 6.7).

3.3.5.1 Lumber. Lumber components shall conform to the quality and structural classification requirements of MIL-STD-731. Sizes of all lumber specified herein shall be nominal as specified in MIL-STD-731, and shall be the minimum acceptable sizes for lumber components.

3.3.5.2 Plvwood. Plywood shall conform to NN-P-530, Group A or B. Softwood plywood (Group B) shall comply with PS-1, Grade C - D interior with exterior glue. Hardwood plywood (Group A) shall comply with ANSI/HPMA HP, grade 3 - 4, type I.

3.3.5.3 Nails and staples. Nails and staples shall be steel and shall conform to FF-N-105.

3.3.5.4 Bolts, nuts, and washers. Bolts shall conform to FF-B-584, Type I, Class 1, Style A. Nuts shall conform to FF-N-836, Type I or II, style 1 or 4.

Washers shall conform to FF-W-92, Type A, Grade I, Class A.

3.3.5.4.1 Lag - bolts. Lag bolts shall conform to FF-B-561, Type I, Grade B.

3.3.5.5 Strapping,. Strapping shall conform to ASTM D 3953, Type 1 or 2 as applicable. Finish shall be A , B, or C.

3.3.5.6 Barrier material. Barrier material, for crate liners, shall conform to PPP-B-1055, class as appropriate for crate liners.

3.3.5.7 Roofing felt. Roofing felt for crate tops shall conform to SS-R-501, 45-pound minimum weight.

3.3.6 Construction.

3.3.6.1. Nailing procedure. Nails used shall be sinkers, coolers, corkers, or common. Nail sizes specified for the fabrication of the various crates are based on Groups I and II woods. When Group III or IV woods are used, nail sizes may be onepenny size smaller than those specified. The patterns to $e used for

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Not for Resale, 04/27/2015 08:41:33 MDTNo reproduction or networking permitted without license from IHS the nailing of two flat pieces of lumber shall conform to the details shown in figure 1 or as specified herein. Unless otherwise specified herein, the following requirements.shal1 determine size, placement, and quantity of nails:

a.

b.

C.

d.

e.

f.

h.

i.

All adjacent crate members shall be securely fastened to each other, either directly or by means of the covering.

A l l nails that are not to be clinched shall be cement-coated, Nails shall be driven through the thinner member into the thicker member wherever possible.

Nails for fastening plywood to framing shall be clinched at least 1/4 inch. Heads of nails shall always be on the plywood side.

When the flat faces of pieces of lumber are nailed together and the combined thickness is 3 inches or less (except for top joists and covering material), nails shall be long enough to pass through both thicknesses and shall be clinched not less than 1/4 inch or more than 3/8 inch.

When the flat faces of pieces of lumber are nailed together and the combined thickness is more than 3 inches or when the flat face of one or more pieces is nailed to the edge or end face of another, nails shall not be clinched. The portion of the nail in the thicker piece shall not be less than 2 times the length of the nail in the thinner piece for tenpenny nails and smaller, and not less than 1-1 /2 inches for twelvepenny nails and larger.

When splitting occurs with the use of diamond-point nails, the nails shall be slightly blunted. When blunting does not prevent the splitting, holes slightly smaller than the diameter of the nail shall be drilled for each nail, Nails shall be driven so that neither the head nor the point projects above the surface of the wood. Occasional over-driving will be permitted, but nails shall not be over-driven more than one-eighth the thickness of the piece holding the Read.

Nails shall be positioned not less than the thickness of the piece from the end not less than one-half the thickness of the piece from the side edge of the lumber whenever possible. Nails driven into the side edge of lumber shall be centered on the side edge.

Nails securing plywood sheathing to frame members shall be spaced as shown in figure 32 . Machine driven nails having a definite head may be used for securing plywood sheathing providing they meet size requirements specified herein.

3 . 3 . 6 . 2 Stapling;. Staples may be used to fasten sheathing to frame members;

they shall not be used for fabrication of bases, fastening of framing members to each other, or for assembly of crates. Staples shall have crowns of not less than 3/8 inch wide and shall have a wire diameter of not less than 0 . 0 6 2 inch (16 gage), Straight leg staples shall be long enough to provide a minimum 1/4-inch clinch; divergent point staples shall not be less than 1 h c h long.

Spacing of staples shall be the same as for nails specified herein. Staples shall always be driven from the plywood side.

3 . 3 . 6 . 3 Bolt amlication. Holes shall be prebored to receive carriage bolts and shall be the exact diameter of the bolt. The lead holes for lag bolts shall be the same diameter as the shank, even though the threaded portion may have a greater diameter than the shank, and shall be as shown in table I. a

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TABLE I . Lag - bolt lead hole s izes , I Diameter of I Diameter of Lead Hole (inch) Threaded Portion I of Lag Bolt I Groups I , II, and I Group I V

(inch) I III Woods I Woods I I

3/16

5/16 7/16 1/2 5/8 v 4

Lag bol ts shal l be placed by be ing tu rned in the i r ho les the fu l l l ength o f the b o l t and shal l not be dr iven in with a hammer or by any similar means. If , fo r any reason, the thread in the wood is s t r ipped when the l ag b lo ts are placed, the l ag bo l t sha l l be removed and placed in a new hole near the old posit ion. A f l a t washer s h a l l be used under the head of each lag bolt and under the nut of each carriage bolt . After the nut is placed, the thread of the carriage bolt projecting beyond the nu t sha l l be painted with a suitable metal primer or similar material .

3.3.6.4 SDlices. Splices and b u t t j o i n t s made i n frame members and skids of long crates shall be as shown in f i gu re 2 .

3.3.6.5 InsDection doors. When specified (see 6.2), one o r more inspection o r access doors shall be provided. Doors shal l be of the s ize and i n t h e locat ion specif ied by the procuring agency and w i l l be used for inter im inspection or servicing of contents. Doors s h a l l be bui l t wi thout cut t ing the frame members and shall be hinged a t the top and fastened by l ag screws a t the sides and bottom as shown in f i gu re 22 . Cleats and s tops shal l be made of 1-inch material, Doors shal l be made of the same type and thickness material used for sheathing. Holes shall be provided through the door and an adjacent frame member f o r a seal wire and lead seal bearing the inspectors' stamp. When hinges with exposed screws are used, the hinge side of the door shall also be sealed.

3.3.6.6 Ventilation. All c ra t e s sha l l be provided with ventilating holes or s l o t s which shall be located a t each end o r a t ends and sides of lumber and plywood sheathed crates, or around the perimeter of plywood and lumber sheathed crates. These vent i la t ing holes or s lots shal l be located immediately below the top frame member and be provided with a ba f f l e as shown in f i gu re 2 1 when s l o t s are used i n plywood dheathed crates or when ho le s a r e i n c lu s t e r s i n lumber sheathed crates. Single holes dr i l led without baff les shal l be s loped a t 45 degrees to drain outward. No ho le s o r s lo t s sha l l be cu t i n any frame member.

3.3.6.6.1 Class 1 crates. Class 1 c ra t e s sha l l be provided with ventilating holes , 3/4 inch in diameter. The c ra t e l i ne r sha l l be removed from the ven t i l a t ing area and a l l sp l in t e r s and chips shall be removed from the holes.

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TABLE II. Ventilation hole reauirements.

3.3.6.6.1.1 End ventilation. Ventilating holes shall be provided in each end in one or more clusters, placed near the upper frame members, provided with a baffle, and spaced 2 inches on center as shown in figure 21. In small crates, holes may be located so that diagonals or struts can be utilized in part for cleats. In crates over 10 feet in length, the ventilating holes shall be divided equally between the sides and ends with a baffle provided for each group of holes. The clusters of holes shall be located as near the midpoint of the side and end as practical. The number of holes shall comply with table II.

3.3.6.6.1.2 Perimeter ventilation. As an alternate to end ventilation, the 3/4 inch ventilating holes may be spaced evenly around the perimeter of the crate just under the top frame member and drilled at a 45 degree angle to drain outward. The total number of holes shall comply with table II.

3.3.6.6.2 Class 2 crates.- Class 2 crates shall be provided with a horizontal slot in each end. The ventilation slots shall be provided with baffles and screens as shown in figure 21. The required ventilating area shall comply with table II. In crates over 10 feet in length, the ventilation area shall be divided equally between the sides and ends of the crate with baffle and screen provided for each ventilating area. The ventilating area shall be placed as near the midpoints of the sides and ends as practical. In small crates, 3/4-inch-diameter holes may be substituted for the slots in the proportion of two holes for each square inch of required area.

Lumber-sheathed crates I Plywood-sheathed crates lEnd ventilation I Perimeter I lminimum number I ventilation I

Volume of lof 3/4 inch I (alternate) I Area required in crate ldiameter holes ITotal minimuml each end lrequired in each Inumber of 3/41 lend (place in linch diameter1 lcluster and use lholes re- I Ibaffle). lquired around1 I I I

(CU. ft.) I

I perimeter I I(space evenly1 (Use baffle and screen) land slope to I ldrain out. I (sq. in.)

0-100 100- 150 250- 200 200 - 400 400 - 600 600- 800 800-1,000 1,000-1,200 1,200 and over

I 3 I 4 I S I 9 I 14 I 18 I 22 I 27 I 33 I

I 7 I 10 I 14 I 27 I 40 I 52 I 66 I 80 I 100 I

- I I I Note: In large crates, where a large ventilating area is required, two or more slots OK clusters of holes may be used in each panel.

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MIL-C-104C B1 = 9999906 0511772 5

MIL-C-lO4C

3.4 Class 1 crates, Class 1 crates may be either bolted or nailed. Bolted crates shall be so designed that the major components of base, sides, ends, and top may be assembled to each other with lag bolts in order that the crate can be readily disassembled and, if desired, reassembled without major damage to the parts. Nailed crates are assembled with nails and straps, are not easily demountable, and because of probable damage during disassembly, are not generally reused. When specified (see 6.2), a combination of top, side, and end panels may be fabricated and assembled to each other as specified for nailed crates, and the unit fastened to the base as specified for bolted crates.

3.4.1 Bases. Bases shall be designed to support the weight of the crated article only when the sides and ends are fastened in place (see 6.6).

3.4.1.1 Style a (skid-type). Style a bases shall consist of longitudinal skids and rubbing strips, headers, load-bearing floorboards, and flooring as shown on figures 4 and 5. Details of construction shall be the same for bolted and nailed crates.

3.4.1.1.1 Skids. Any species of wood except Group I shall be used for skids. Skids shall be spaced no farther apart than 48 inches, center to center, across the width of the base. Minimum size shall be as shown in table III.

When either the length or net load exceed the maximum shown, the next larger skid shall be used.

TABLE III. Allowable minimum skid sizes.

Maximum I Maximum length I Nominal size of skids (in.)

net load(1b. ) I of crate (ft. ) I

I I 300 I 16 I 2 x 4 (flat) 1/

1,000 I 12 I 2 x 4 (flat) 1/ 2,000 I 20 I 3 x 3 or 3 x 4 (flat) 2/ 10,000 I 32 I 4 x 4

I I 30,000 I 20 I 4 x 6 (on edge)

1/ For nailed crates only.

2/ For crates with 2-inch-thick lower frame member or 2-inch end struts.

When necessary, skids may be spliced o r laminated according to the details shown in figure 2 or 3, but the use of 2- by 4-inch skids shall be limited to such lengths that no splicing would be required. Whenever possible splices shall be made not more than one-third of the length of the base from the ends of the skid and the splice locations alternated in adjacent skids. To prevent splitting, all skids shall have a carriage bolt placed crosswise and 2 to 3 inches back from each end of the skid as shown in figures 4 and 24. Bolt sizes shall comply with table IV,

3.4.1.1.2 Rubbing strip for skids. Rubbing strips of 3-inch thick lumber, the same width as the skids, shall be attached to the skids with two staggered rows o f nails spaced 12 inches apart in each row. The nails shall be driven through the rubbing strip into the skid, shall be of such length as to penetrate a minimum of approximately 70 percent of the skid thickness, and shall not protrude through the skid, The strips shall be beveled full depth at an angle of 45 degrees at sling and forklift openings. Openings in the rubbing strips for forklift-truck access shall be 12 inches its length, 28 inches center to

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Pl IL-C-104C B1 W 999990b ~ 0511773 ~~ 7 W

MIL-C-104C

center, and positioned to straddle the center of balance of the loaded crate, Sling openings not less than 4 inches in length, and preferably 8 inches, shall be provided at the ends of the rubbing strip where permitted by the length of the crate and by the location of the forklift-truck access openings. No center pieces of the rubbing strips shall be less than 16 inches in length. On crates 5 feet and less in length, the forklift openings shall be omitted; end sling openings shall not be less than 6 inches long and shall serve as both forklift and sling openings, 3 . / c , 1.1.3 Headers. Headers shall be placed at each end of the base and shall be bolted to each skid with one carriage bolt. Sizes of headers and bolts shall be as shown in table IV.

3.4.1.1.4 Forklift members. The forklift members shall consist of the header and two members of equal size, spaced 20 and 40 inches (on center) from each end of the skids and bolted as shown in figure 4. Where the form of the short or narrow, 2-inch-thick lumber shall be used in the 48-inch end areas as shown in figure 5. When 2-inch lumber is used in the forklift area and intermediate skids are required because of the width of the base, the 2-inch forklift members shall be bolted to the intermediate skids. Forklift members shall be bolted to the intermediate skids. Forklift members shall be notched or set back as specified for headers in 3.4.1.1.3. If loaded containers center of balance is other than the center of the base, the space for forklift entry shall be positioned so that the center of balance is centered in between forklift openings.

1 item to be crated makes it impractical to use these members, or when crates are

O TABLE IV. Required header sizes and carriape bolt sizes.

I I

I I Skid size (in.) I Header size (in.) I Bolt Diameter (in.)

2 x 4 I 2 x 4 1 / I 3/8 3 x 3 I 3 x 3 I 3/8 3 x 4 I I 4 x 4 I 4 x 4 I 1/2 4 x 6 I

I I 1/ For nailed crates only in width to 48 inches. For wider crates or bolted crates, use 3 x 3 .

Headers shall be of a single piece and not built up to two or more pieces to meet the dimension requirements. Headers shall be placed atop the plywood when plywood flooring is used. Headers shall be placed a distance back from the ends of the skids equal to the thickness of the end sheathing. The ends of the headers shall be notched for bases floored with lumber; ends of headers for plywood floored bases shall be set back from the outside edges of the outer skids (see figures 4 and 5). The notched and set back distances shall be equal to the thickness of the lower frame members of the skids.

I 3.4.1.1.5 Load-bearing floorboards. Load-bearing floorboards shall be

~0 placed where the concentrated loads of the contents occur. The cross section shall be determined from table X. The forklift members and any 1- or 2-inch flooring may be considered as load-bearing within limits of their assigned

I values, The ends of load-bearing floor boards shall be notched or set back from

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3.4.1.1.3 (see figures 4 and 5). Load-bearing floorboards 4 inches wide shall be bolted to each skid with one carriage bolt, and load-bearing floorboards over 4 inches wide shall be bolted to each skid with two carriage bolts, and the intermediate skid where one is required. Bolt diameters shall be the same as specified in 3.4.1.1.3 for corresponding skid sizes.

3.4.1.1.6 Lumber flooring. Lumber floorboards shall be neither less than 1 inch thick nor less than 4 inches wide, and shall be placed at right angles to the skids. Boards shall be spaced 1/4 inch apart for drainage and the ends placed flush with the outside face of the skids, When a large area of the base is floored with 2-inch thick lumber, the use of filler strips 2 inches wide shall be used along each side over the thinner flooring to equal the thickness of the 2-inch flooring as shown in figure 5. The filler strips shall be nailed to the flooring with two staggered rows of sixpenny nails spaced 10 inches apart. Nailing of floorboards to skids shall be as shown on figure 1 and as specified in 3.3.6.1.

3.4.1.1.7 Pl-wood flooring, Plywood 3/8 inch in thickness, may be used in place of 1-inch lumber flooring as shown in figures 4 and 5, but not as load-bearing floorboards. Plywood flooring shall be laid flush with the outer edges of the skids and with the face grain perpendicular to the skid length.

Headers and load-bearing floorboards shall be placed on top of the plywood and bolted to the skids after the plywood has been nailed in place. Plywood flooring shall be nailed to each skid with two rows of sevenpenny nails, staggered and spaced 6 inches apart in each row. A spacing of 1/4 inch shall be allowed between sheets of plywood for drainage. When 1/3 to 1/2 the area of the base is floored with 2-inch boards, the plywood flooring shall be used only between these areas. Filler strips shall be nailed over the plywood as shown on figure 5, with nailing as specified in 3.4.1.1.6.

3.4.1.1.8 Drainage. A drainage hole, 1/2 inch in diameter, shall be drilled adjacent to each header or load-bearing member in each outer edge of each plywood floored section of the base (a "section" being a portion of the base in which water might be trapped) (figure 4 and 5). Care shall be taken to locate the holes so that the holes will not be covered when the contents are placed on the base of the crate,

3.4.1.2 Style b (sill-tyDel. Style b bases shall be constructed as shown in figure 6. The load contained on Style b bases shall always be transmitted to the side sills by means of intermediate sills or by the article itself.

3.4.1.2.1 Side and end sills. The size of the side sills shall be determimed from table XI. End sills shall be of the same size as side sills.

The side sills shall overlap the end sills as shown in figure 6. Sills shall be laminated as shown in figure 3, when necessary.

3.4.1.2.2 Intermediate sills and load-bearing headers. Intermediate sills shall be applied crosswise of the base. The size of intermediate sills shall be determined from table XII. The weight used to determine the size of an intermediate sill shall be that amount of the load actually supported by that sill. Load-bearing headers shall be of the same size as intermediate sills.

Load-bearing headers and intermediate sills will not be required when all of the load is supported by the side sills. Load-bearing headers shall be attached at their ends to intermediate sills and intermediate sills shall be attached at

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3.4.1.2.5 Rubbing strips. Style b bases shal l have rubbing strips of 3-inch thick material , the width of which sha l l no t be less than 4 inches. The rubbing s t r i p s s h a l l always be applied lengthwise of the base and positioned under each longitudinal member. When required, intermediate rubbing strips of the same s ize a re loca ted so that the c lear dis tance between rubbing strips does not exceed 36 inches, Other requirements shall be as specified in 3.4.1.1.2.

MIL-C-104C

t h e i r ends to s ide s i l ls by a combination of nailing and the use of metal s t r ap hangers fabricated from 1-1/4 inches wide by 0.035 inch thick nail-on strapping as shown in f i gu re 7 .

3.4.1.2.3 Bridping. Intermediate si l ls s h a l l be bridged a t t h e ends with 1-inch lumber and at intervals along the span not exceeding 4 feet with 2-inch lumber of the same depth as the intermediate si l ls (see f igure 6 ) .

3.4.1.2.4 Bottom Sheathing. Style b bases shall be sheathed on the bottom with lumber securely nai led to the bottom surface of the si l ls at right angles to the d i rec t ion of the s ide si l ls . Boards s h a l l be 4 t o 10 inches wide and of not less than 1-inch material for spans of less than 30 inches between longitudinal members and of not less than 2-inch material f o r spans of 30 inches or more. Bottom sheathing shall be flush with the outside face of a l l s i d e and end si l ls and be spaced 1/4 inch apart for drainage. One-inch boards shall be nailed with eightpenny nails, 2-inch boards with twelvepenny n a i l s , and na i l ing shal l be as shown in f i gu re 1.

3.4.2 Tops. Tops s h a l l be double sheathed and s h a l l be (a) narrow, widths through 54 inches; (b) intermediate, widths over 54 inches through 60 inches;

(c) wide, over 60 through 120 inches in width. Plywood sheathing 1/4 inch th i ck , sha l l be attached to the lumber framing with i ts face grain paral le l wi th the width of the top and i ts edges flush with the outside edges of the framing.

All j o i n t s of the plywood sheathing shall be made over j o i s t s o r o the r frame members. Roofing fel t , or polyethylene f i lm not less than 4 mils th ick , sha l l be applied over the plywood with a minimum 4-inch overlap .at joints. A nonhardening caulk o r mastic shall be applied in the overlap area. Top sheathing boards not less than 4 inches wide s h a l l be placed over the plywood sheathing and waterproof barrier and shall extend beyond the outer edges of the top framing by an amount equal t o the thickness of s ide and end panel sheathing less 1/8 inch. Headers joining the jois ts together shal l be 1 inch thick by the depth of the jo i s t s for in te rmedia te and wide tops.

3.4.2.1 Narrow tops. Narrow tops s h a l l be framed on 2- x 4-inch members as shown in f i gu re 8 . Top sheathing board shall be applied parallel to the width of the top and s h a l l be of single pieces. A t plywood j o i n t s on the inside of the top, 2 - x 3-inch pieces shall be used as shown in f igure 8 .

3.4.2.2 Intermediate tops . Intermediate tops shall be framed on 2-inch j o i s t s placed f l a t and headers 1 inch by the thickness of t he . j o i s t s , The- top sheathing boards shall be placed parallel to the length o f the top (see figure 9 ) . When the crate length is over 10 f e e t , end j o i n t s w i l l be permitted in top sheathing boards. All j o in t s sha l l be made over j o i s t s , two j o i n t s s h a l l be adjacent to each other, and not more than one-third of the jo in ts sha l l be made over any one j o i s t .

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M I L - C - 1 0 4 C 81 m 9999906 051177b 2 m '

MIL-C-104C

3.4.2.3 Wide tow. Wide tops shall be constructed simi-lar to intermediate tops except that the wide tops shall be framed in joists and headers placed on edge as shown in figure 10.

3.4.2.4 Fabrication nailing;. Fabrication nailing of tops shall be as shown on figures 11 and 12. All plywood members shall be nailed on at least three edges.

3.4.2.5 Grabhook reinforcing ioists for lifting crates. When no joists are used or when a joist does not coincide with the center of balance, a reinforcing joist shall be placed at the center of balance to distribute the load when the crate is lifted with a single set of grabhooks. Reinforcing joists shall conform to the requirements of table V.

3.4.2.6 Lamination of ioists. When two members are to be nailed together for joists and are 1 and 2 inches thick, respectively, they shall be nailed with sevenpenny nails with the nailheads in the thinner piece. When both members are 2 inches thick, twelvepenny nails shall be used, Nails shall be staggered in two rows at least 1 inch from the edges, and shall be 18 inches apart in the rows.

3.4.2.7 Alternate plvwood sheathed top. For tops not exceeding 96 inches wide, single sheathing of 1/2-inch thick plywood may be used in lieu of the double sheathed top. Face grain of the plywood shall be parallel with the width of the top, Framing members and joists shall be as specified for double sheathed tops. When joists do not coincide with plywood joints, a joint cover of 1- x 4-inch lumber shall be used on the inside of the top. Prior to securing the plywood to the joists or joint covers, caulking of a nonhardening type shall be applied at three places at each joint - between the plywood panels at their butt joint, and between the plywood and joint cover or joist on either side of the butt joint. The caulk shall be applied as a continuous bead and may be either performed or applied with a gun.

TABLE V. ReinforcinP ioist reauirements.

I I Size of single I Gross loads not I Length of joist reinforcing (in.) I exceeding (lb.) I not exceeding (in,)

I 2 x 4 I 2 x 4 I 2 x 4 I 2 x 4 I 4 x 4 I 4 x 4 I 4 x 4 I

I 1 , O00 I 72 2,000 I 60 3,000 I 48 5 , O00 I 36

15,000 I 72 10 , O00 I 96

22,000 I 60 I I

When the gross loads exceed 22,000 lb or where the width exceeds 96 inches for any load over 10,000 lb, two 4- by 4-inch joists shall be used; one placed approximately 2 to 3 feet each way from the center of balance, for the use of two sets of grabhooks.

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3.4.3 Sides,

3.4.3.1 Number and type of panels. Sides shall be constructed as shown i n f igures 13, 14, and 15. In crates with s tyle b bases, the sheathing of s ides and ends shal l reach below the lower horizontal frame member a distance equal to the depth of the si l ls p lus f loor thickness , less 1/8 inch. The type of side panels shall vary with the inside crate height as specified in table V I .

TABLE V I . Side panel types - c lass 1 cra tes .

I I Inside height of I Type of I Reference c r a t e ( i n . ) I panel I f igure No.

I I I I

Over 24 t o 60 I A I 13 Over 60 t o 108 I B I 14 Over 108 t o 144 I C I 15

I I

The number of panels for each fu l l l ength s ide sha l l be computed by dividing the inside crate length by the inside height, and using the nearest whole number,

3.4.3.2 Member select ion. The s izes of the upper and lower frame members, s t r u t s , and diagonals shall be determined from tables X I I 1 t o XXII except as otherwise specified. Loads referred t o in the tables àre the net loads and the dimensions are the inside measurements of the c ra te . The member s izes sha l l be based on Group II woods. I f the exact s ize of the crate is not given in the t ab le s , member s izes for the crate of the next greater length and width, and the next smaller height shall be used.

3.4.3.2.1 Uwer and lower frame members. Except where v e r t i c a l j o i s t supports are required, upper frame members for crates over 54 inches wide s h a l l always be 2 inches thick and a minimum of 2 by 4 inches in size. Splicing of upper or lower frame members s h a l l be done over o r under a s t r u t and shal l be as shown in f i gu re 2 .

3 .4 .3 .2 .2 Vert ical s t ruts , Vert ical s t ruts shal l be cont inuous from the lower frame member to the upper frame member and the diagonal and horizontal braces shal l be cut in between. The end s t r u t s s h a l l be as shown i n t a b l e V I I .

TABLE V I I . End strut reauirements.

I Nominal s i ze o f end s t r u t s I I I

Net load ( lb.) i Bolted crate ( in. ) i Nailed crate ( in. )

1,000 o r under I Over 1,000 but under 5,000 I 5,000 and over I

2 x 4 I 2 x 4 3 x 3 I 2 x 4 4 x 4 I 2 x 4

I I

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MIL-C-104C B 1 W 999990b 0533778 b

3.4.3.2.3 Horizontal braces. Horizontal braces for Types B and C panels (figures 14 and 15) shall be the same thickness as the struts and 4 inches wide,

3.4.3.2.4 Diagonals. Size of diagonals shall be as specified in the member selection tables XIII to XXII and shall be located as shown in figures 13, 14, and 15. When frame members are 1 inch thick, gusset plates shall be cut from l/4-inch plywood and shall be 12 inches minimum, in the shortest dimension. The corners shall coincide with the center line of the diagonals as shown in figure 1 6 .

3.4.3.2.5 Joist supports. The upper frame members shall serve as supports for tops. When crates are 6 feet wide and 12 feet high or 8 feet wide and 10 feet high (tables XIII to XXII) and when the struts are 1 inch thick, vertical joist supports shall be provided as shown in figure 1 6 . These shall consist of 2- by 4-inch members placed on and nailed to the frame members of the side and extending under each interior joist to the floor.

3.4.3.3 Liners, A crate liner shall be applied between the sheathing and frame members of sides and ends of all lumber-sheathed crates and shall conform to the crate liners specified in PPP-B-1055. The paper shall be placed horizontally as unrolled, with a 4-inch minimum shingle lap applied for proper drainage and shall cover the entire framed area. Vertical joints, when required, shall have a minimum 4-inch lap and shall be located at a vertical member.

3.4.3.4 Sheathing. Sheathing for the side and end panels of crates shall be applied vertically, shall extend to the bottom of the skids on side panels and to the tops of skids on the end panels of skid type base crates. Sheathing shall extend to the bottom of sills on sill-type base crates. Sheathing shall be either tongue-and-groove or square and shall be 1 inch thick. At least one side of all boards shall be dressed and the dressed side placed outward. No boards shall be less than 4 inches in width. End boards shall be not less than 6 inches wide and preferably wider. No more than 10 percent of the boards (not more than one out of 10 boards) shall be of the minimum width, nor shall the narrow boards be adjacent to each other. Short boards, not less than 2 feet in length, may be used under the following conditions (figure 17): (1) boards shall be cut at right angles, (2) the center of a short sheathing board shall be at the approximate center of the width of a diagonal and shall have full coverage by the diagonal, or shall be joined on a horizontal member, (3) at least every second board and all end boards shall be full length, and (4) nailing shall be as shown in figure 17.

3.4.3.5 Fabrication nailinq. Nails securing sheathing to framing up to and including 2 inch thickness shall be driven through the sheathing and shall be of such length as to permit a minimum of l/4-inch clinch on the framing. For nailing sheathing to horizontal and diagonal frame members 4 to 6 inches wide, three rows of nails shall be used, There shall be a minimum of three nails per crossing in sheathing boards 4 to 6 inches wide and a minimum of four nails in wider boards (figure 17). For nailing sheathing to horizontal and diagonal frame members over 6 inches wide, four rows of nails shall be used. There shall be a minimum of four nails per crossing in sheathing boards 4 to 8 inches wide and a minimum of five nails in wider.boards (figure 17). For nailing sheathing to struts 4 to 6 inches wide, two rows of nails shall be used. The nails shall be spaced approximately 8 inches apart in each row and staggered, For wider struts use three rows of nails. The nails shall be spaced approximately 12

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Not for Resale, 04/27/2015 08:41:33 MDTNo reproduction or networking permitted without license from IHS inches apart and staggered (figure 17). Nail spacing at vertical butt joints shall be as shown in figure 17. Gusset plates shall be secured with sevenpenny nails driven through and clinched on the sheathing, Nailing shall be shown in figure 16. Vertical joist supports shall be secured with two tenpenny nails at each horizontal frame member crossing and one tenpenny nail at each diagonal crossing as shown in figure 16. Where vertical joists coincide with struts, there shall be two rows of nails on 30-inch centers.

3.4.3.6 Lag screw reinforcing strap for bolted crates. Reinforcing strap shall be used on side and end panels of all demountable crates as shown in figures 13, 14, 15, and 18. Galvanized steel strap, punched or drilled, 1-1/4 inches by 0.035 inch for 3/8-inch lag screws, and 2 inches by 0.050 inch for 1/2 and 5/8-inch lag screws, shall be nailed to the inner face of the sheathing between the lower edge of the bottom frame member and the bottom of the sheathing as shown in figure 18. The strap shall be located to coincide with the center o€ the skid or header and shall be nailed on maximum 2-inch centers to the sheathing with clout or similar nails. Nails shall be clinched at least 3/8 inch.

3.4.4 Ends. End types and size of members for ends in crates over 30 inches wide shall be determined in a manner similar to the sides, except that in all cases the thickness of the upper and lower frame members shall be the same as the struts specified in table XII1 to XXII. The member arrangement shall conform, to the details shown in figure 19. For crates less than 30 inches wide, single diagonals only are required and all frame members shall be 1 by 4 inches in size as shown in figure 20.

3.4.5 Assembly (Class 1 cratesl.

3.4.5.1 Bolted crate.

3.4..5.1.1 General. Type II (bolted) crates shall be assembled with lag bolts (see 3.3.9.4.1). Lead holes shall be used for lag bolts.

3.4.5.1.2 Fastening sides to base. The sides shall be secured to the skids with lag bolts. For 3- by 3-inch or 3- by 4-inch skids, 3/8 inch diameter by 3-inch long lag bolts shall be used; for 4 - by 4-inch skids, 1/2 inch diameter by 4-inch long lag bolts shall be used; and for 4- by 6-inch skids, 5/8 inch diameter by 4-inch long lag bolts shall be used. The number of lag bolts shall be as specified in table XXIII. One-half the number shall be used on each side and the spacing shall be uniform along the skid. Maximum spacing shall be 16 inches for 3/8-inch lag bolts and 20 inches for 1/2-inch lag bolts. Lead holes shall conform to 3.3.6.3 in size and shall be drilled in line with and through the center o€ the metal reinforcing strap, as well as through the sheathing and into the skid. Assembly and placement details shall be as shown on figures 23 and 24.

3.4.5.1.3 Fastening sides to OR. Lag bolts, 3/8 inch diameter by 3-1/2 inches long, shall be used to fasten the sides to the top. These lag bolts shall be placed so that there is one in the end of each joist at the approximate center (figure 25). For tops without joists, lag bolts shall be placed at the approximate center of the side frame member of the top and spaced no greater than 24 inches apart.

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MIL-C-1O4C

3.4.5.1.4 Fastening ends to top. sides, and base. Lag bolts for fastening ends to tops shall be 3/8 inch in diameter by 2-1/2 inches long. Lag bolts for fastening ends to sides shall be 3/8 inch diameter by 3-1/2 inches long, Placement and other assembly details shall be as shown in figures 23 and 25.

Lag bolts for fastening ends to base shall be the same size as specified in

3.4.5.1.2. Location and spacing shall be as shown in figures 23 and 24. Lead holes shall be centered on the reinforcing strap.

3.4.5.2 Nailed crate.

3.4.5.2.1 General. Type I crates shall be assembled with nails and metal straps. General rules for crate assembly shall be as shown in table XXIV and figures 26 and 27.

3.4.5.2.2 Fastening sides and ends to base. Sides and ends shall be nailed to the skids and headers with cement-coated nails (figure 26). Two rows of nails shall be used for 2- by 4-inch, 3- by 3-inch, 3- by 4-inch, and 4- by 4-inch skids or headers and for style b bases. The number OE nails required for the perimeter of the crate shall be as shown in table XXV, and based on the gross load. Nail spacing shall be no greater than 6 inches in each row, and no less than two nails shall be used in each sheathing board.

3.4.5.2.3 Fastening ends to.sides and sides to ends. The end panels shall be nailed to the side panels with twentypenny cement-coated nails spaced 12 inches apart as shown in table XXIV and figure 26. The nails shall pass through the sheathing and the edge struts of the ends into the edge of the corner struts of the sides. Predrilling shall be used for these nails to prevent splitting and the bit for drilling shall be approximately 75 percent of the diameter of the nail shank. The edge sheathing boards of the side panels shall be nailed to the edge struts of the ends with eightpenny cement-coated nails spaced 6 to 8 inched apart (figure 26).

3.4.5.2.4 Fastening top to sides and ends. Tops shall be fastened to sides and ends with corner reinforcing straps and tensioned straps with anchor plates as shown in figure 27. Corner straps shall be of such length as to allow nailing into framing of sides and ends.

3.4.5.3 Strapping. Strapping shall be used as shown in figure 27 on all bolted crates with net loads over 3,000 lb and for all nailed crates.

Tensioned metal strapping and corner straps shall conform to ASTM D-3953, Type 1 or 3, Zinc-Coated finish, Grade 2, not less than 3/4 inch wide by 0.028 inch thick. Corner strapping shall be prepunched or drilled, In addition, on crates with Style b bases, corner reinforcing straps shall be applied at the bottom corners as shown in figure 28. Nails shall be 1-1/4- to l-1/2-inch galvanized roofing nails. A minimum of three nails shall be used for each strap leg and strapping shall be located so that nailing is in a frame member.

3.5 Class 2 crates. Class 2 crates shall be Type I or II as specified and shall have the same use limitations as described for lumber-sheathed in 3.4.

3.5.1 Bases. 'The construction of bases shall conform to bases of Class 1 crates as specified in 3.4.1. Details of construction shall be as shown in figures 4, 5, 6, and 7.

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Over 24 to 60 Over 6 0 to 96 Over 96 to 144

MIL-C-LO4C A L rn 9999906 05Ll178L b rn

MIL-C-104C

3.5.2 Tops. The construction of tops for Class 2 crates is identical to that described for Class 1 tops in 3.4.2. Details of construction shall be as shown in figures 8, 9 , IO, 11, and 12.

3.5.3 Sides.

3.5.3.1 Number and type of panels. Types of panels for various heights and corresponding illustrative figure numbers shall be as shown in table VIII.

TABLE VIII. Side panel types - class 2 crates.

I I

Inside height of crate I Type of panel I Figure No.

I I I I

A B C

I I

Type B panels include a horizontal brace and Type C panels have two horizontal braces. These shall be located so as to equally divide the space between upper and lower frame members. For a l l types of side panels, struts shall be spaced 24 inches on centers except at one or both ends so that 48-inch-wide plywood can be utilized with a minimum of waste. Sides shall be constructed as shown in figures 29, 30, and 31. In crates with Style b bases, the sheathing of sides and ends shall reach below the horizontal frame member a distance equal to the depth of the sills.

3.5.3.2 Member selection. The sizes of the upper and lower frame members and struts shall be determined from tables XIII to XII, except as otherwise specified, Loads referred to in the tables shall be the net loads and the dimensions shall be the inside measurements of the crate. The member sizes shall be based on Group II woods. If the exact size of the crate is not given in the tables, member sizes for the crate of the next greater length and width, and the smaller height, shall be used.

3.5.3.2.1 Umer and lower frame members. The requirements for upper and lower frame members shall comply with those described for lumber-sheathed side panels in 3.