I am building a tool and I have issues understanding  these dimensions. I cannot find what this symbol means Ø . This tool is 48 in. long and is 25 in in width . This figures do not jive http://screencast.com/t/PWjiFgmlrMIp http://screencast.com/t/31F0r8t17Mq http://screencast.com/t/cMTCXmp9iQ This last image are confusing. Also, what do these symbols mean. Ø and [ ] in the dimensions.  

Happy New Year

Crousie