- 7-1 Introduction
- 7-2 Terminology and Conventions-ANSI
- 7-3 Adding Dimensions to a Drawing
- 7-4 Drawing Scale
- 7-5 Units
- 7-6 Dimensioning Holes and Fillets
- 7-7 Dimensioning Counterbored and Countersunk Holes
- 7-8 Angular Dimensions
- 7-9 Ordinate Dimensions
- 7-10 Baseline Dimensions
- 7-11 Locating Dimensions
- 7-12 Fillets and Rounds
- 7-13 Rounded Shapes-Internal
- 7-14 Rounded Shapes-External
- 7-15 Irregular Surfaces
- 7-16 Polar Dimensions
- 7-17 Chamfers
- 7-18 Symbols and Abbreviations
- 7-19 Symmetrical and Centerline Symbols
- 7-20 Dimensioning to a Point
- 7-21 Dimensioning Section Views
- 7-22 Dimensioning Orthographic Views
- Chapter Projects
7-7 Dimensioning Counterbored and Countersunk Holes
Counterbored holes are dimensioned in the sequence of their manufacture. First the hole’s diameter is given, then the counterbore diameter, then the depth of the counterbore.
Figure 7-36 shows a part that contains two counterbored holes; one goes completely through and the other is blind. Dimensions will be applied to both.
1 Create a block.
2 Click the Hole Wizard tool, click the Counterbore option, and insert the counterbored hole that goes completely through.
3 Specify the Standard as ANSI Inch, the Type as Hex Screw, the Size as a 3/8 diameter, and the End Condition as Through All.
See Figure 7-37. SolidWorks will automatically select the diameter for the counterbored hole that will accommodate a Ø3/8 Hex Head Screw.
Depending on your default settings, the counterbored hole may have a small chamfer added. The countersink can be removed by removing the check mark in the Options box on the Hole Specification manager.
4 Position the hole using the given dimensions.
5 Add the second hole, setting the End Condition to Blind and 1.00 deep.
6 Position the hole using the given dimensions.
7 Save the block as Block, Cbore.
8 Start a new Drawing document and create a front and a top orthographic view of the Block, Cbore.
9 Click the Annotation tab and add all dimensions and centerlines other than the hole dimensions.
10 Click the Hole Callout tool.
See Figure 7-38.
11 Click the edge of each hole, move the cursor away from the hole, and click the mouse when a suitable location is found.
The counterbored hole’s dimension note is interpreted as shown in Figure 7-38.
Figure 7-39 shows the Block, Cbore assembled with hex head screws inserted into the counterbored holes. SolidWorks will automatically generate the correct size counterbored hole for a specified screw. The counterbore depth will align the top of the screw head with the top surface of the part and will define a hole diameter that includes clearance between the fastener and the hole. In this example a clearance hole with a diameter of Ø.40 was generated. The hole is .02 larger than the specified .38 fastener diameter.
If clearance is required between the top of the screw and the top surface of the part, check the Head clearance box under Options in the Hole Specification section of the Hole Wizard PropertyManager. See Figure 7-40.
The diameter of the counterbored hole can be made larger than the clearance generated by SolidWorks to allow for tool clearance. Tool clearance allowance increases the diameter of the counterbore so that it is large enough to allow a socket wrench to fit over the head of the fastener and still fit within the hole.
Counterbored Hole with Threads
Figure 7-41 shows a block with two counterbored holes. Both holes are threaded.
1 Create the block.
2 Click the Hole Wizard tool, select the Straight Tap option, and specify a 3/8-16 UNC thread that goes completely through.
3 Click the Positions tab and locate the hole.
4 Click the green OK check mark.
This will locate a 3/8-16 UNC thread hole in the block. Now, we add the counterbore.
5 Click the top surface of the block and click the Sketch option.
6 Click the Circle tool and draw a Ø.88 circle on the top surface centered on the same centerpoint as the Ø3/8-16 hole.
The dimensions for this example came from Figure 7-38.
7 Click the Features tab, click the Extruded Cut tool, and specify a cut depth of 0.27.
8 Click the green OK check mark.
9 Repeat the procedure, adding a second hole with a thread to a depth of 0.85.
See Figure 7-42.
10 Save the block as Block, Threads.
11 Create a new Drawing document and create front and top orthographic views of the Block, Threads.
12 Add centerlines to the front view and add dimensions as shown.
See Figure 7-43.
13 Use the Hole Callout tool and click the left threaded hole.
Do not click the outside of the counterbored hole. This will generate a note that includes only the counterbore. In Figure 7-42 the callouts 3/8-16 Tapped Hole appear on the front view. Remove the callouts from view by right-clicking the callouts and selecting the Hide option. The thread information will be included in the counterbore hole callout.
14 Locate the text and click the mouse.
The initial note may show the counterbore callout above the thread callout. Convention calls for the note to read in the sequence of manufacture. The threaded hole is cut first and then the counterbore is added; therefore, the thread callout should come before the counterbore callout.
15 Modify the callout to list the thread callout above the counterbore callout.
Access the Dimension Text box on the Dimension Manager by clicking the .31 THRU ALL dimension, delete the first line of text, and replace the dimension with a new dimension, 3/8-16 UNC THRU.
16 Click the green OK check mark.
17 Click the threaded portion of the right hole.
18 Locate the text and click the mouse.
19 Modify the callout as shown.
Figure 7-44 shows dimensioned counterbored holes using metric units. The Hole Callout tool was used to dimension the counterbored holes. Note that the hole’s diameter is listed as Ø11. The fastener size was specified as M10, and the Ø11 hole is a clearance hole.
Dimensioning Countersink Holes
Countersink holes are used with flat head screws to create assemblies in which the fasteners do not protrude above the surfaces.
Figure 7-45 shows a part with two countersunk holes; one goes completely through, the other has a depth specification.
1 Draw a block.
2 Use the Hole Wizard tool, click the Countersink type, specify the ANSI Metric standard, select an M10 size for a flat head screw, and specify a hole that goes all the way through. Define a head clearance of 2.00mm.
3 Click the Positions tab and position the countersunk hole’s centerpoint as shown using the Smart Dimension tool.
4 Click the green OK check mark.
5 Click the Hole Wizard tool, click the Countersink type, specify the ANSI Metric standard, select an M10 size for a flat head screw, and specify a depth requirement of 25.00mm for a Blind hole. Define a head clearance of 2.00mm.
6 Click the Positions tab and locate the hole as shown.
7 Click the green OK check mark.
8 Save the drawing as Block, CSink.
Dimensioning the Block
1 Create a new Drawing document with a front and a top orthographic view of the Block, CSink.
2 Use the Smart Dimension tool and add the appropriate dimensions.
3 Use the Center Mark tool to add a centerline between the two holes indicating they are aligned.
4 Click the Annotation tab, click the Hole Callout tool, and dimension the two countersunk holes.
See Figure 7-46.