Dimension tolerance annotation in AutoCAD - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is a dimension tolerance annotation in AutoCAD?

It is a note added to a dimension that shows the allowed variation in size, ensuring parts fit and work properly.

beginner

How do you add a tolerance to a dimension in AutoCAD?

Select the dimension, open the properties, and enter the tolerance values in the tolerance fields or use the DIMTOL command.

intermediate

What are the two main types of dimension tolerances?

Limit tolerances (upper and lower limits) and plus-minus tolerances (a nominal size with plus and minus values).

beginner

Why is dimension tolerance annotation important in engineering drawings?

It controls manufacturing accuracy, ensures parts fit together, and prevents costly errors or rework.

intermediate

What command in AutoCAD helps to display tolerance symbols automatically?

The DIMTOL command lets you set and display tolerance annotations with symbols like ± or limits.

Which command in AutoCAD is used to add tolerance annotations to dimensions?

A DIMLINEAR

B DIMSTYLE

C DIMTOL

D DIMALIGNED

DIMTOL is the command specifically for setting and displaying dimension tolerances.

What does a plus-minus tolerance indicate?

A Nominal size with allowed plus and minus variation

B Exact size with no variation

C Only upper limit size

D Only lower limit size

Plus-minus tolerance shows a nominal size plus and minus allowed variation.

Why are dimension tolerance annotations critical in drawings?

A To decorate the drawing

B To confuse the reader

C To increase drawing size

D To control manufacturing accuracy

They ensure parts are made within acceptable size limits to fit and function properly.

Which tolerance type shows upper and lower size limits explicitly?

A Limit tolerance

B Plus-minus tolerance

C Geometric tolerance

D No tolerance

Limit tolerance shows exact upper and lower size limits.

How can you edit tolerance values after adding a dimension in AutoCAD?

A Use the erase command

B Use the properties palette

C Use the zoom command

D Use the line command

Tolerance values can be edited in the properties palette of the dimension.

Explain what dimension tolerance annotation is and why it matters in technical drawings.

Think about how small size changes affect assembly.

Describe the difference between limit tolerance and plus-minus tolerance in dimension annotations.

Consider how each type displays allowed size range.

Practice

1. What is the main purpose of dimension tolerance annotation in AutoCAD?

easy

A. To show allowable size variation in a dimension

B. To change the color of dimension lines

C. To add text notes unrelated to size

D. To create 3D models from 2D drawings

Solution

1. Step 1: Understand dimension tolerance annotation

   Dimension tolerance annotation indicates how much a dimension can vary and still be acceptable.

2. Step 2: Identify the correct purpose

   Showing allowable size variation matches the definition of tolerance annotation.

3. Final Answer:

   To show allowable size variation in a dimension -> Option A

4. Quick Check:

   Dimension tolerance = allowable size variation [OK]

Hint: Tolerance shows size limits, not colors or notes [OK]

Common Mistakes:

• Confusing tolerance with color or text formatting
• Thinking tolerance creates 3D models
• Ignoring the size variation meaning

2. Which AutoCAD command is used to set the style of dimension tolerance display?

easy

A. DIMTM

B. DIMSTYLE

C. DIMLINEAR

D. DIMEDIT

Solution

1. Step 1: Recall commands related to dimension tolerance

   The DIMSTYLE command manages overall dimension styles, including tolerance display settings.

2. Step 2: Compare with other commands

   DIMTM is not a standard AutoCAD command; DIMLINEAR creates linear dimensions, DIMEDIT edits dimensions but does not set tolerance style.

3. Final Answer:

   DIMSTYLE -> Option B

4. Quick Check:

   DIMSTYLE sets tolerance display style [OK]

Hint: Use DIMSTYLE to set tolerance style, not DIMTM [OK]

Common Mistakes:

• Choosing DIMTM which is not a standard command
• Confusing DIMLINEAR with tolerance settings
• Using DIMEDIT which edits dimension text

3. Given the following AutoCAD commands sequence:

DIMTM
Set Tolerance Display to Limits
DIMTOLJ
Set Tolerance Justification to Above

What will be the effect on the dimension tolerance annotation?

medium

A. Tolerance values will show as plus/minus and appear inside the dimension line

B. Tolerance values will be hidden and appear below the dimension line

C. Tolerance values will show as limits and appear above the dimension line

D. Tolerance values will show as limits but appear below the dimension line

Solution

1. Step 1: Analyze DIMTM setting

   Setting Tolerance Display to Limits means the tolerance shows as upper and lower limit values.

2. Step 2: Analyze DIMTOLJ setting

   Setting Tolerance Justification to Above places the tolerance text above the dimension line.

3. Final Answer:

   Tolerance values will show as limits and appear above the dimension line -> Option C

4. Quick Check:

   Limits + Above = Tolerance values will show as limits and appear above the dimension line [OK]

Hint: Limits means upper/lower values; Above means text position [OK]

Common Mistakes:

• Mixing up limits with plus/minus display
• Confusing text position above vs below
• Ignoring the effect of DIMTOLJ

4. You set the tolerance display style using DIMTM to 'Symmetrical' but the tolerance text does not appear on your dimension. What is the most likely cause?

medium

A. Tolerance values are set to zero or missing

B. The dimension style is locked and cannot show tolerance

C. You forgot to run DIMTOLJ to position the text

D. The dimension line is too short to show tolerance

Solution

1. Step 1: Understand Symmetrical tolerance display

   Symmetrical tolerance shows plus/minus values around the dimension.

2. Step 2: Identify why text might not appear

   If tolerance values are zero or missing, no text will show even if style is set.

3. Final Answer:

   Tolerance values are set to zero or missing -> Option A

4. Quick Check:

   Zero tolerance means no text shown [OK]

Hint: Check tolerance values before adjusting text position [OK]

Common Mistakes:

• Assuming DIMTOLJ is required to show text
• Blaming dimension style lock without checking values
• Thinking line length hides tolerance text

5. You need to annotate a dimension with a tolerance that shows upper and lower limits clearly above the dimension line, but your drawing has overlapping text. Which combination of commands and settings will best solve this?

hard

A. Use DIMTOL to hide tolerance and manually add text above

B. Use DIMTM to set Symmetrical display and DIMTOLJ to set tolerance text to Centered

C. Use DIMTM to set Deviation display and DIMTOLJ to set tolerance text to Below

D. Use DIMTM to set Limits display and DIMTOLJ to set tolerance text to Above

Solution

1. Step 1: Choose tolerance display style

   Limits display shows upper and lower tolerance clearly, which fits the requirement.

2. Step 2: Position tolerance text

   Setting tolerance text to Above via DIMTOLJ moves text above the dimension line to avoid overlap.

3. Step 3: Evaluate other options

   Symmetrical or Deviation do not show limits clearly; hiding tolerance loses info; manual text is less efficient.

4. Final Answer:

   Use DIMTM to set Limits display and DIMTOLJ to set tolerance text to Above -> Option D

5. Quick Check:

   Limits + Above = clear, non-overlapping tolerance [OK]

Hint: Limits + Above text avoids overlap and shows clear tolerance [OK]

Common Mistakes:

• Choosing symmetrical which shows plus/minus, not limits
• Setting text below causing overlap
• Hiding tolerance instead of adjusting display