When doing mechanical design work, it’s pretty hard to avoid speccing screws for a design. I don’t really remember the dimensions for metric screws so I am finding that I need to look them up all the time. I’ve found a very useful site for this (link below). It’s got a nice diagram telling you which dimension is where and it’s got values for:
- Nominal Size
- Thread Form Type
- Major Diameter
- Pitch
- Root Radius
- Pitch Diameter
- Minor Diameter (Male Thread)
- Minor Diameter (Female Thread)
- Thread Height (Male Thread)
- Thread Height (Female Thread)
- Tap Drill Diameter
Link: http://www.newmantools.com/tech/threadm.htm
Update 24 Sept 2011: Added info about screw head dimensions
http://www.csgnetwork.com/screwsochdcaptable.html