Create a unified template suitable for both detail and assembly drawings adhering to ASME or ISO standards (depending on location). Include a title block positioned in the bottom right corner containing company or organization details, names of personnel responsible (designer, checker, approver), drawing title, revision reference, sheet size, view alignment conventions, and primary scale. 

Ensure the title block includes a section for default tolerances not shown alongside dimensions on the drawing. Above the title block, include a parts list detailing any additional components required for assembly, referencing each part to the drawing by its title or page number.

Make sure the drawings are properly scaled to fit the page, ensuring clear visibility of dimensions in each view. If sending the part for manufacturing internationally, it's advisable to use the metric system for dimensions. When uncertain, employing a dual-dimension layout with both sets of measurements is recommended.

It is generally advisable to select appropriate tolerances for modern CNC machines, typically around +/- 0.005 inches for distance dimensions. Accurate Machine Products outlines standard tolerances for various processes in its manufacturing guidelines. 

Tolerances may be tailored based on part design and production method, but adhering to standard tolerances helps align design expectations and control costs. Tolerances tighter than the standard range are classified as "tight tolerances," while those broader are termed "loose tolerances."

Once drafting begins, it's crucial to adhere to the correct projection alignment specified. This orientation guides the manufacturing process, ensuring all views align with the convention detailed in the title block. In the US, third angle projection is standard, while first angle projection is more prevalent in Europe.

If space permits, including a 3D isometric view is beneficial for machinists during part manufacturing. These views do not require alignment with orthographic views but should be drawn from the correct corner to convey the desired orientation. Avoid adding dimensions to the isometric drawing due to its scale differences, but include relevant notes. Isometric views provide additional details about the part in three dimensions and can illustrate critical information such as installation directions for inserts or pins in assemblies.

Excessive hidden lines and tangent lines can diminish the clarity of a drawing. Include only essential hidden lines; others can be noted and highlighted in an isometric drawing or detailed in an exploded view for smaller features.

Position dimensions outside the view and avoid overlapping dimension lines for clarity. Ensure no redundant dimensions appear across different views or are already implicit in the 3D model within specified tolerances. Dimension critical areas, reference dimensions, GD&T requirements, threads, and surfaces as necessary. For arcs greater than 180 degrees, specify diameter; for arcs under 180 degrees (e.g., fillets), use radius. Right-angle intersections do not need angle dimensions. Include informational dimensions in parentheses for reference, like total length derived from multiple smaller dimensions.

Simply stating the metal type is insufficient. Stainless Steel 304, for instance, varies with four different ASTM specifications based on its application. Specify any specific surface finishing instructions such as edge breaks and deburring clearly in the notes section of the drawing.

Specify complete thread specifications for threaded features, including thread form, series, major diameter, threads per inch, class of fit, and depth. Standard threads are recommended for ease of tooling use; for custom threads, provide a detailed view to define the thread form fully.

In manufacturing, engineers use tolerances to specify acceptable variation for dimensions, ensuring parts maintain form, fit, and function. Three main types of tolerances are commonly used:

1. Bilateral Tolerances: Allow variation in both positive and negative directions from the nominal dimension (e.g., ±0.005”).

2. Unilateral Tolerances: Permit variation in one direction only from the nominal dimension (e.g., +0.005” / -0.000”).

3. Limit Dimensions: Specify the largest and smallest acceptable values; any dimension between these limits is acceptable (e.g., 0.525” / 0.520”).

Bilateral tolerances are typically used for general dimensions, while unilateral tolerances and limit dimensions are employed for critical fit and tight tolerance features, ensuring clarity and readability of the drawing.

GD&T, or Geometric Dimensioning and Tolerancing, is a method engineers use to precisely communicate requirements to manufacturers. It uses symbols, datums, and geometric characteristics to define allowable variations in features. GD&T includes form, orientation, location, run-out, and profile tolerances, each specifying different aspects of a part's geometry. 

Standardized symbols and methodologies ensure clear communication with manufacturers, although it's crucial not to over-define drawings with GD&T, which can complicate interpretation.

To ensure clarity in specifying complex finishing or masking requirements, use color-coded views or cross-hatching for clear guidance. Include process specifications, such as for anodizing, directly in the call-out to avoid ambiguity and aid manufacturers and post-processors in accurate execution.