#Screwdriver bits drivers#

This drive system increases driving surface by including an additional cross section (at 45° angles) withing the large cross. The Phillips company improved upon their Phillips drive system by developing Pozidriv bits and fasteners.

Easily confused with less-common 'cross' and 'Frearson' driving systems.

Can withstand more torque than slot drive systems before camming-out.

Prevents over-tightening by allowing for cam-out.

Phillips bits are sized by simple, round numbers, such #1, #2, #3, etc. Since their introduction in the 1930's, improvements in power tools that allow users to set tools at fixed torque have encouraged production of new drive systems that reduce cam-out even further. Although their tendency to cam-out increases wear to bits and fasteners, they cam-out much less easily than slot systems and reduce the risk of damaging the material being worked on as they prevent over-tightening. Phillips bits have rounded corners at their cross sections and blunted tips which are designed (intentionally) to allow the bit to cam-out at a specific torque range to prevent over-tightening. First, the cross design greatly increases the driver's contact area with the fasteners, allowing more positions for bits to engage fasteners, and increasing the overall grip of the bit.

The Phillips drive system improves upon the slot system in many ways. Tightly fitting bits and fasteners can be difficult to find between brands.Increased cam-out with slot bits and fasteners increases their wear rate.Only two available positions (at 180° to each other) for bits to engage fasteners.

#Screwdriver bits drivers#

Drivers of different sizes can be used to turn fasteners.Their shape makes slot fasteners easy to turn with common objects.This is especially true of their width measurement on the driving face, as most manufacturers do not list this measurement with bit length and other specifications. With the fewest points of contact of any system, slot bits cam-out at very low torque.Īlso, it is hard to find slotted fasteners and bits that match exactly between brands, because of the wide-spread, more-or-less unstandardized manufacture of slotted tools and fasteners. Cam-out is much more likely with drive systems that have fewer points of contact between the bit and the fastener, like the slot system. The 'slot' or 'slotted' drive system is one of the oldest fastening systems, and it is the most simple. To extend the life of power bits, it's best for shoppers to buy high quality bits made from wear-resistant materials.Metal balls inside a quick change chuck engage a power bit's power groove when the bit is installed. Quick change chucks are increasingly popular and standard to many impact drivers/wrenches. Power Bits Because power bits are generally more expensive than insert bits, they're usually bought to last longer than insert bits.Ī power bit's power groove is shaped for use in quick change adapters and chucks. Because of their low cost, insert bits are an especially good choice for drive systems that tend to wear bits down through frequent cam-out, or any application where bits are expected to wear through frequent, heavy use.The snap ring notch on the bodies of insert bits helps them hold firmly in bit holders. Their expendability remains their greatest strength.Īlthough they are often installed directly into jaw chucks by users, insert bits were originally designed to fit in the ends of extension adapters. Insert Bits Insert bits are small and inexpensive.

Designs with more contact points to the fastener distribute pressure more evenly, have more driving power due to increased contact area, can handle more torque before camming-out, will cam-out less, and will wear more slowly by consequence.īefore discussing the different drive systems available on the market, shoppers can tackle a much simpler decision between insert bits and power bits as discussed below. A lot can be understood about a screwdriver bit drive system just by looking at the shape of its point. A drive system's tendency to cam-out also affects how quickly or not the bit will wear. Some drive systems will cam-out at lower torques, others at higher torques. 'Cam-out' is what happens when the rotational force of a screwdriver bit causes it to disengage the fastener and slip out. Different drive designs, like Phillips, square, and torx, allow bits to drive fasteners at different torque settings before camming-out.

But if you can choose drive type first, there are some things to consider about drive designs to match them to your application. If a bit is being purchased for specific fastener, then the drive type of the bit is obviously determined already. Choosing drive type is the most important decision when shopping for screwdriver bits.