Engineering link collection

I'm not a mechanical engineer, so let's collect links to quickly look up best practices, part nomenclature (e.g. bearing name codes) and similar information
Obviously this blog posting will be updated every so often

Best practices

• How to Build your Everything Really Really Fast (*great* collection of best practices)

Stationary

• HtByERRF step 2 and 3,4 "T-slots and finger joints"
• HtByERRF step 7 and 8 "strengthening links and parts"
• HtByERRF step 9 and 10 "spacers, standoffs, tensioning", 11 "shapes"

 Nuts and Bolts

• Gizmo's Notes on "Nuts and Bolts" (also vocabulary)
• imperial tap hole sizes

Moving

  Bearings

• Notes on Ball Bearings (See "Common Bearing Dimensions")

 Shafts and couplings 

• HtByERRF step 15 and 16 "rotating live axles" 
• also (see "Aluminum can shims") 
• Vocabulary 

 Planar linkage

• HtByERRF step 18
  

Electrical

 Wires

• Wire Gauge (imperial)Drill Sizes

General

• Engineering Toolbox (Ad ridden site)  
• Roy Mech
• Notes on...