2. Holes 3 Basic Types Drilled - Straight Cylinder Counterbore - Two cylinders, one on top of the other. Used to receive a bolt head. Countersink - A cone on top of a cylinder. Used to accept a flat head bolt/screw.

3. Hole Types Hole Counterbore - receives a bolt head Countersink - receives a flat head screw or bolt

4. Hole Feature Placement A hole feature requires a hole center point sketched on an existing feature. You can also select endpoints or center points on existing geometry as hole centers.

5. Threaded Holes Threads can be added to holes for bolts or screws. There are several types of threads series. Each is identified by their: Major DiameterMajor Diameter Threads Per InchThreads Per Inch Thread Series IdentificationThread Series Identification Ex. 9/16 - 12 UNC This represents a thread with a major diameter of 9/16”, 12 threads per inch and is a standard Unified National Course thread.

6. Thread Patterns UNF - Unified National File UNC - Unified National Course UNS - Unified National Special UNEF - Unified National Extra Fine ISO - International Standards UN - American National (External Thread) UNR - American National (Internal Thread)

7. Unified National Thread Form Depth Rounded Root Pitch

8. American National Thread Depth Pitch Flat Root Very similar to Unified National Threads but has a Flat Root.

9. Metric Thread Forms - ISO Depth Pitch Flat Root

10. Thread Annotations Thread Depth - Internal Unified And American Threads.5 - 13 UNC - 2A _.75 Major Diameter # of Threads per Inch Thread Series - UNF, UNC, UN, UNR Class of Fit 1=large tolerance, 2=General purpose, 3=low tolerance1=large tolerance, 2=General purpose, 3=low tolerance A=External, B=Internal Blank=Right hand, LH=Left Hand

11. Thread Annotations ISO Thread Forms M12 X 1.5--6H Designates Metric Nominal Major Diameter in millimeters X means by Thread Pitch in millimeters followed by a dash # Between 3 & 9 identifies grade of tolerance 3 - 5 Fine, 6 is most common, 7-9 Course3 - 5 Fine, 6 is most common, 7-9 Course Letter Denotes Thread Tolerance H=low, G=tightLetter Denotes Thread Tolerance H=low, G=tight H or G for Internal, g or h for ExternalH or G for Internal, g or h for External