1. Threads and Fasteners

2. Thread Terminology

3. Thread Callouts - Metric
(mm)
(mm)
(mm)

4. Thread Callouts – ANSI Unified
1 – loosest fit
2 – normal fit
3 – most exact fit
B represents internal thread
(in)
UNC – Unified National Course
UNF – Unified National Fine
UNEF – Unified National Extra Fine
UN – Unified National

5. Thread Callouts – ANSI Unified
Assumes course threads with a nominal fit (2).
(in)

11. Goal:
connect the top part to the bottom part using a .75” long #10-24 cap screw which has a head taper of 82˚

12. Steps:
buy the screw
drill a countersunk hole without threads into the top part
drill a threaded hole in the bottom part

13. 2 things to know if you tap a hole
the thread length should be at least twice the diameter of the hole
if you use a bolt to connect some bodies
the bolt should extend beyond the nut by at least two thread pitches

16. Was able to download a SolidWorks part file of this cap screw.

17. Use ‘hole wizard’ to place a tapered hole, through all, for a #10 flat head screw with an 82˚ head taper.

18. Note that the major diameter of a #10 screw is 0
Note that the major diameter of a #10 screw is 0.19” so we have clearance.

19. Use ‘hole wizard’ to place a tapped hole for a #10-24 screw.
I selected a hole depth of 0.51” and a threaded depth of 0.38” (typically there should be at least 2  dia. of thread, i.e. at least 0.38” of thread).

20. This is the ‘default’ drawing after inserting dimensions from part file.

21. This is the ‘default’ drawing after inserting dimensions from part file.
delete this one
hide this one
Add the hole callout.

26. Design Library Tools -> Add in -> SolidWorks Toolbox
SolidWorks Toolbox Browser

27. Assembly with washers
Select a 3/8-24 bolt to connect the parts.

28. Assembly with washers and nut

29. Determining Bolt Length

30. Bolt length calculation
Bolt must be 1.92” long plus the distance of 2 extra pitches.
The bolt has 24 threads per inch. Two extra pitches will require an extra 1/12” of an inch.
Total minimum length is = 2.003” .
Find the next longest available bolt.

31. Smart Fasteners

32. 2 things to remember if you tap a hole
the thread length should be at least twice the diameter of the hole
if you use a bolt to connect some bodies
the bolt should extend beyond the nut by at least two thread pitches