Mechanical Drawing Standards Manual Pdf

[In Libman]

Anyengineering drawing should show everything: a complete understanding of the object should be possible from the drawing. If the isometric drawing can show all details and all dimensions on one drawing, it is ideal. One can pack a great deal of information into an isometric drawing. However, if the object in figure 2 had a hole on the back side, it would not be visible using a single isometric drawing. In order to get a more complete view of the object, an orthographic projection may be used.

Which views should one choose for a multiview drawing? The views that reveal every detail about the object. Three views are not always necessary; we need only as many views as are required to describe the object fully. For example, some objects need only two views, while others need four. The circular object in figure 6 requires only two views.

Repeatedly measuring from one point to another will lead to inaccuracies. It is often better to measure from one end to various points. This gives the dimensions a reference standard. It is helpful to choose the placement of the dimension in the order in which a machinist would create the part. This convention may take some experience.

To prepare a drawing, one can use manual drafting instruments (figure 12) or computer-aided drafting or design, or CAD. The basic drawing standards and conventions are the same regardless of what design tool you use to make the drawings. In learning drafting, we will approach it from the perspective of manual drafting. If the drawing is made without either instruments or CAD, it is called a freehand sketch.

This cross-sectional view (section A-A, figure 17), one that is orthogonal to the viewing direction, shows the relationships of lengths and diameters better. These drawings are easier to make than isometric drawings. Seasoned engineers can interpret orthogonal drawings without needing an isometric drawing, but this takes a bit of practice.

The diagonal lines on the section drawing are used to indicate the area that has been theoretically cut. These lines are called section lining or cross-hatching. The lines are thin and are usually drawn at a 45-degree angle to the major outline of the object. The spacing between lines should be uniform.

A second, rarer, use of cross-hatching is to indicate the material of the object. One form of cross-hatching may be used for cast iron, another for bronze, and so forth. More usually, the type of material is indicated elsewhere on the drawing, making the use of different types of cross-hatching unnecessary.

Usually hidden (dotted) lines are not used on the cross-section unless they are needed for dimensioning purposes. Also, some hidden lines on the non-sectioned part of the drawings are not needed (figure 12) since they become redundant information and may clutter the drawing.

The purpose of dimensioning is to provide a clear and complete description of an object. A complete set of dimensions will permit only one interpretation needed to construct the part. Dimensioning should follow these guidelines.

An arrowhead is approximately 3 mm long and 1 mm wide. That is, the length is roughly three times the width. An extension line extends a line on the object to the dimension line. The first dimension line should be approximately 12 mm (0.6 in) from the object. Extension lines begin 1.5 mm from the object and extend 3 mm from the last dimension line.

In order to get the feel of what dimensioning is all about, we can start with a simple rectangular block. With this simple object, only three dimensions are needed to describe it completely (figure 26). There is little choice on where to put its dimensions.

This drawing is symmetric about the horizontal centerline. Centerlines (chain-dotted) are used for symmetric objects, and also for the center of circles and holes. We can dimension directly to the centerline, as in figure 31. In some cases this method can be clearer than just dimensioning between surfaces.

The District Department of Transportation (DDOT) Compendium lists policies and procedures for managing the District of Columbia's (District) transportation network and public space. The Standards and Manuals section of the DDOT Compendium contains a full list of all Standards and Manuals.

The Standard Specifications for Highways and Structures are standard for all DDOT contracts awarded by the Mayor of the District, the Council of the District, and/or the Contracting Officer. The Standard Specifications shall also be used for all the construction activities and material control within the Public Space of the District.

This manual has been prepared to assist the DDOT and its Consultants in the inventory, inspection, appraisal, and load rating of bridges under the District's jurisdiction in accordance with the Manual for Bridge Evaluation published by the American Association of State Highway and Transportation Officials (AASHTO). The program detailed in this manual will help implement the National Bridge Inspection Standards (NBIS) as issued by FHWA.

The Manual on Uniform Traffic Control Devices for Streets and Highways (MUTCD) is a document issued by the Federal Highway Administration (FHWA) of the United States Department of Transportation (USDOT) to specify the standards by which traffic signs, road surface markings, and signals are designed, installed, and used.

The following Right-of-way (ROW) policies and procedures are intended to establish a fair and efficient process for completing ROW acquisitions and transfers, consistent with federal and local regulations.

These documents provide the policies and procedures for utility accommodation and relocation within the Public Space for DDOT construction projects. The Manual establishes a fair and efficient process for completing utility work, consistent with federal and local regulations and DDOT Standards. In addition, this Manual is intended to be the companion of the DDOT Design and Engineering Manual, and together provide the utility coordination and technical requirements required to accomplish utility accommodation and relocation in advance of or in conjunction with DDOT construction projects.

The purpose of these documents is to provide guidance to practitioners in the implementation and management of work zones throughout the District, as well as provide the basis for the developing various work zone related documents.

The Drafting and Design Presentation Standards Manual (DDPSM) provides guidelines for the management of design quality in the planning and design of road infrastructure projects. It also sets the policy and drafting standards for presenting the design to provide a consistent interface with the road construction industry.

This manual provides the means for designers to deliver a design fit for its intended purpose, comply with all legislative and corporate requirements and enhance the potential for the project to be constructed in accordance with 'the design' through the supply of appropriate construction information.

We currently offer language translations on our site primarily through Google Translate. This helps visitors find and use information in the languages they speak, but the tool is not perfect. Automated translation may be inaccurate or errors may display on translated pages.

The King County Road Services Division has developed a Computer Aided Drafting and Design (CADD) Standards Manual (4MB PDF) and CADD Engineering Drawings (see below) for use by CADD users in the division, as well as consultants who are working on projects for the division.

The CADD Standards Manual provides standards and guidelines in the creation of civil and structural engineering plans and documents of all construction projects for the division. The manual consists of four chapters and they are as follows:

Adoption of the 2010 Standards also establishes a revised reference point for Title II entities that choose to make structural changes to existing facilities to meet their program accessibility requirements; and it establishes a similar reference for Title III entities undertaking readily achievable barrier removal.

State and local government facilities must follow the requirements of the 2010 Standards, including both the Title II regulations at 28 CFR 35.151; and the 2004 ADAAG at 36 CFR part 1191, appendices B and D.

If the start date for construction is on or after March 15, 2012, all newly constructed or altered State and local government facilities must comply with the 2010 Standards. Before that date, the 1991 Standards (without the elevator exemption), the UFAS, or the 2010 Standards may be used for such projects when the start of construction commences on or after September 15, 2010.

(1) Each facility or part of a facility constructed by, on behalf of, or for the use of a public entity shall be designed and constructed in such manner that the facility or part of the facility is readily accessible to and usable by individuals with disabilities, if the construction was commenced after January 26, 1992.

(i) Full compliance with the requirements of this section is not required where a public entity can demonstrate that it is structurally impracticable to meet the requirements. Full compliance will be considered structurally impracticable only in those rare circumstances when the unique characteristics of terrain prevent the incorporation of accessibility features.

(ii) If full compliance with this section would be structurally impracticable, compliance with this section is required to the extent that it is not structurally impracticable. In that case, any portion of the facility that can be made accessible shall be made accessible to the extent that it is not structurally impracticable.

(iii) If providing accessibility in conformance with this section to individuals with certain disabilities (e.g., those who use wheelchairs) would be structurally impracticable, accessibility shall nonetheless be ensured to persons with other types of disabilities, (e.g., those who use crutches or who have sight, hearing, or mental impairments) in accordance with this section.

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