Screwdrivers

Phillips screwdriver, Reed & Prince screwdriver, Clutch screwdriver, Slotted screwdriver, Robertson screwdriver, Eaton screwdriver, Pozidrive screwdriver, Torx screwdriver,

Just about everyone is familiar with the standard screwdriver. The part you grip is called the handle, the steel part that extends from the handle is called the shaft, and the end that fits into the slot in the screw is called the blade. The size of a screwdriver is normally indicated by its shaft length and blade width. For example, a screwdriver labeled “5/16 x 4” would have a blade width of 5/16 of an inch and a shaft length of 4 inches. Screwdrivers are available in a variety of shaft lengths and blade sizes.

Screwdriver blades are manufactured in different shapes to fit different types of screw heads. A standard blade fits a simple slotted-head screw. Figure 25 illustrates this type of screw head as well as several nonstandard head shapes. The main advantage of these nonstandard shapes is that they provide more contact area between the screw head and the blade, ensuring that the blade won’t easily slip out when you’re turning it. Nonstandard screws are often used to fasten trim materials and moldings on equipment, or wherever the outward appearance of the assembly is important. On such areas, using slotted screws could cause the outer surfaces to become scratched or dented.

When you tighten or loosen a screw, always use a screwdriver with a blade that fits snugly into the screw head slot. If the screwdriver fits improperly or has a damaged tip, the tool could slip and cause damage to the screwdriver, the screw, or the piece on which you’re working.

Observe the following rules when you’re using a screwdriver:
- Always clean the slots in a screw head before attempting to remove it.
- Always hold a screwdriver with its blade at a 90-degree angle to the slot of the screw.
- Make sure that the screwdriver blade fits tightly into a screw slot in order to prevent slips.
- When using a nonstandard screwdriver, exert more pressure on the screw head than you would with a standard screwdriver.
- Never use a screwdriver to cut or remove metal, to punch holes, or to pry—it could easily snap.
- Never hammer on the handle of the screwdriver, since this may cause the handle to split or “mushroom.”
- Never use a screwdriver to work on an object that you’re holding in your other hand. The screwdriver may slip and cause a painful injury. Use a bench vise to hold small objects as you work on them.

Removing old screws can be a problem if a screw is rusted or “frozen” with corrosion, or if the threads are stripped. If you’re trying to remove a screw and it won’t come out, stop working. Check to make sure the screwdriver blade fits the screw slot perfectly. If the blade fits and the screw is still resistant to turning pressure, try one of the following methods to avoid damaging the screw:
- Clean the screw head to remove dirt, grease, or paint.
- If the screwdriver slot is too narrow or worn to accept a screwdriver blade, try using a hacksaw to widen and deepen the slot.
- Use a penetrating lubricant to help dissolve any rust or corrosion around the screw head. Penetrating lubricants can be purchased at most automotive parts stores.
- Tap the head of the screw lightly with a punch. The rust and corrosion will often be knocked loose from the screw.

If a screw is extremely tight and can’t be removed by using any of the methods above, you can use a special tool called an impact screwdriver. An impact screwdriver has various tips that can fit into screw heads. Unlike ordinary screwdrivers, an impact screwdriver is designed to be struck with a ball peen hammer. When the end of the impact screwdriver is struck, it produces a twisting motion at the blade that loosens the screw. This turning of the blade occurs at the same time that it’s driven into the screw by the impact of the hammer, so the blade won’t easily slip out of the screw head.