The Difference Between Pozidriv Vs. Phillips: An Expert Guide
In the world of screws and screwdrivers, understanding the difference between Pozi and Phillips is not just about semantics—it can significantly impact the efficiency of your work and the longevity of your tools. Before we delve deeper into the nuances of these two popular screw drive types and their corresponding screwdrivers, let's look back at their origins.
The Inception of Pozi Vs Phillips
Phillips screwdrivers were first patented in 1935 by Henry F. Phillips. If you’ve ever wondered where the Phillips drive gets its name, now you know. Introduced as an improvement on the widely-used flat head drive, the Phillips drive was actually invented by Portland mechanic John Thompson but named after its legal patent owner, Mr Phillips.
The driving force (pun intended) behind the Phillips head creation was to improve upon the basic, yet flawed, flat-head formula which was susceptible to slipping out and difficult to align when it came to mass production. The Phillips design quickly became popular due to its self-centring design feature, which was ideal for the burgeoning assembly line industries of the time. It addressed the slipping out issue, however, the Phillips design had an Achilles heel versus the traditional slotted drive which was that it became more prone to camming out at high torques.
Another interesting design choice of the Phillips drive was that it offered some semblance of screw retention. The original patent for the Phillips drive states that “a screw may be first secured to the end of a driver, and presented to the work to be dealt with without the inconvenience of the screw dropping from the end of the driver.” The 1934 patent also argues that this design allows fasteners to be installed with one hand, a relatively innovative feature which may now be taken for granted.
The Pozidriv (an abbreviation of 'Positive Drive') screwdriver emerged later in 1962. It was developed by the American Screw Company and GKN Screws and Fasteners as an improved version of the Phillips, specifically designed to address the cam-out problem associated with Phillips screws while also making other improvements across the board.
|Head Type||Slotted Head||Phillips Head||Pozi Head|
|When was it invented?||Invented pre-1600||Invented 1934||Invented 1962|
|Why was it invented?||Basic drive||Improvement upon slotted drive||Improvement upon Phillips drive|
|What is the drive shape?||One slot||Four radial slots||Eight radial slots|
|How is it located?||Manual alignment||Self-centralising||Self-centralising|
|Will it cam-out?||Can easily slide out||Slight resistance to cam-out||Improved resistance to cam-out|
|What is the tip shape?||Flat tip||Angular tip||Shallow angular tip|
|How many flutes?||No Flutes||Tapered flutes||Parallel flutes|
The Difference Between Pozi and Phillips Screws
You only need to observe their appearance and design when assessing the difference between Pozi and Phillips head screws. The standard Phillips screw has a cross at the centre, and the slots of this cross are straight. They converge at a point directly in the centre of the screw head.
In contrast, the Pozi screw has a similar cross design, but with an additional smaller cross offset at a 45-degree angle to the primary cross. This difference between Pozi and Phillips screws grants Pozi the advantage of better torque transmission, reducing the chance of 'cam-out' or slipping when high torque is applied.
What’s The Difference Between Pozi and Phillips Screwdrivers?
To accommodate the difference between Pozi and Phillips screws, their respective screwdrivers also subtly, yet vastly differ.
As a starting point, Phillips screwdrivers have a pointed angular tip that fits snugly into the screw's recesses. All four radial slots of the cross pattern converge to this tip making alignment, or “self-centering” naturally occur. As you’ll see from the patent diagrams, each flute of the cross shape is tapered, aiding the self-centring design. This gentle slope of the tapered design however encourages the driver to disengage at high torque.
On the other hand, a Pozidriv screwdriver has a much shallower angular tip with a total of eight radial slots which all still converge at the centre. The four primary slots, still in a cross pattern, have a secondary set of four smaller slots set at 45 degrees to the primary ones. The last difference is that the flutes in between each slot are parallel rather than tapered. These three core differences improve upon the main weaknesses of the Phillips drive leading to increased torque transmission, superior reduction to cam out, and all while still retaining the self-centralising feature which caused the widespread adoption of the Phillips in the first place.
Phillips Vs Pozi: Are There Benefits To Phillips Heads?
Despite the ongoing debate of Pozi Vs Phillips, the latter still has significant advantages, especially over slotted drive types.
Phillips screws are better at naturally self-centring, making them perfect for automated assembly lines. They are also widely available and work well for applications that require a less aggressive bite and where the need to reduce cam-out may not be a priority.
Phillips screwdrivers also have the benefit of being able to drive a vast variety of different-sized Phillips screws. The 1936 Phillips patent states that only two sizes of Phillips drivers are required for screw sizes from number 5 to number 16. By contrast, a slotted drive would require 'six or more' sizes of screwdrivers for the same size range.
Lastly, Phillips recesses are manufactured according to a specified selection of sizes however slotted screws and drives are largely defined by the fastener head width. We'd wager you've definitely used an incorrectly-sized slotted screwdriver for a slotted screw head more than once.
The Benefits of Pozidriv Over Slotted & Phillips Drives
Pozi v Phillips: why opt for Pozidriv? The most substantial benefit of Pozidriv lies in its design. It offers better contact with the screw, reducing slippage and increasing torque transmission. Pozidriv screws are excellent for applications requiring high torque or those where power tools combined with Pozi drive bits are used.
Like the Phillips drive before it, the Pozi drive is defined by a small number of regimented sizes however both the screw and screwdriver size must be coupled. Pozi heads are available in ascending sizes of 0, 1, 2, 3, 4, and 5. Pozi sizes can be expressed in several different ways, such as the abbreviation PZ#, or simply a 'number' size.
Make Your Choice, Phillips or Pozi?
So there we have it, understanding the difference between Pozi and Phillips screws and screwdrivers can help you choose the right tool for the job, ensuring more efficient work and better preservation of your tools. Remember, Phillips or Pozi, each has its unique benefits and ideal use scenarios.
How Can You Tell the Difference Between Phillips and Pozi?
The main difference between Phillips and Pozi-driv can be spotted by looking at the screw head. Phillips screws have a simple cross, while Pozidriv screws have an additional, smaller cross, offset by 45 degrees. The other more subtle differences are mentioned above in this article.
Are Pozidriv and Phillips Interchangeable?
While they might appear similar, due to the main difference between Pozi and Phillips, they are not interchangeable. Using a Pozidriv screwdriver on a Phillips head screw can lead to tool damage and inefficient work.
What’s The Difference between Pozi 1 and 2?
Pozi 1 and Pozi 2 refer to the size of the screwdriver tip. Pozi 1 is smaller and used for finer work, while Pozi 2 is larger and used for medium-duty work. The sizes range from PZ0 to PZ5.
Can You Use a Phillips Screwdriver on a Pozidriv Screw?
While you might wonder if it's possible, due to the somewhat similar appearances of Phillips and Pozidriv, it's not recommended. This is primarily because of the differences in tip and slot shapes between Phillips and Pozi's designs. While a Phillips screwdriver may appear to fit into a Pozi screw, the risk of camming out is much higher and you risk stripping the screw head or damaging your tools.
Can You Use a slotted drive on a Phillips or Pozi screw?
While it's technically possible to use a slotted drive on a Phillips or Pozi screw, it's not recommended due to the difference in their designs. The slotted drive is intended for screws with a single, straight-line groove. Using it on a Phillips or Pozi screw, which has 'cross' or 'star' patterns, will likely result in a poor fit. This mismatch can lead to inefficient torque transmission, increased likelihood of 'cam-out' or slipping, potential damage to the screw head, and accelerated wear on your tool.