Table Saw: Can't adjust the blade height
If the table saw blade won't raise and lower easily, blow out sawdust and dirt from the elevating and tilting mechanisms. Lubricate the elevating and tilting mechanisms using graphite or silicone lubricants because they won't attract sawdust. Don't use grease; grease will only attract more sawdust and dirt.
These repairs may help solve your Table Saw problem:
Perform table saw general maintenance
Clean out all sawdust inside the saw cabinet and around the motor. Polish the saw table using an automotive wax. The automotive wax helps keep the table clean and work pieces slide easily over the waxed surface. Clean plastic parts with soapy water. Unplug the table saw, clean the cutting blade with pitch and gum remover.
Replace the table saw blade
The table saw blade becomes dull with use. Cutting hard wood or metal dulls the blade faster. The blade is dull when you must apply significantly more than normal force to push the piece you're cutting through the blade.