A drawer full of screwdriver bits is only useful if you choose the one that actually fits the screw. Some designs look almost interchangeable, but a close match can still be the wrong tool—and leave you with a damaged screw head.
In this MakerBuildIt video, I walk through seven common bit designs, what makes them different, and the mistakes to watch for before turning the next screw.
Flathead: simple, but easy to slip
A flathead, or slotted, screw has one straight slot for a flat blade. You will still find these in older furniture, electrical devices, and restoration projects.
The frustration is keeping the blade in the slot. As I point out in the video, a slipping screwdriver can damage the surface around the screw, which is especially painful on a project you have just refinished.
Phillips: watch the size and cam-out
Phillips is the familiar cross-shaped design found in electronics, appliances, toys, and many other everyday objects. It comes in multiple sizes, so the Phillips bit already in your driver may not be the right one for the screw in front of you.
The video explains cam-out: the bit climbing out of the recess as you turn it. That slipping can damage the screw head. A PH2 bit may be common, but that does not make it the right choice for a smaller Phillips screw.
Pozidriv: similar to Phillips, with a different fit
Pozidriv is easy to mistake for Phillips at a glance. Look for the additional features between the main cross slots. Those details distinguish the drive and help the matching bit engage.
Phillips and Pozidriv are not interchangeable. A Phillips bit may enter a Pozidriv screw without fitting it properly. Before blaming the screw for stripping, check that the bit matches the drive type as well as the size.
Torx and security Torx
Torx is the six-point star-shaped drive, and one of my favorites. The video highlights its torque transfer and engagement, with examples in automotive work, electronics, machinery, and 3D printing.
Security Torx adds a small pin in the center of the screw recess. That pin requires a matching security bit with a hole in its tip. If a regular Torx bit seems blocked from seating, check for the center pin before forcing it.
Hex / Allen: metric and imperial matter
Hex bits have six flat sides. If you work on bicycles, machinery, furniture, or 3D printers, you have probably used them plenty of times.
The key warning is size: hex tools come in both metric and imperial sizes. Two that look close can still fit differently. Using the wrong size can round out the recess and turn a straightforward job into a screw-removal project.
Robertson: the square drive
Robertson uses a square recess and is especially associated with Canadian construction, woodworking, and cabinetry. In the video, I highlight how securely the correct bit can engage the screw, sometimes holding it on the tip without support.
It is another example of why a good fit matters. For woodworking projects where you have a choice of fastener, square drive is one of the designs I encourage you to try.
Spline: identify the fastener first
Spline drives use multiple teeth to engage a matching fastener and are commonly associated with automotive and industrial work. The important warning in the video is about look-alikes: spline, triple-square, and Torx are distinct profiles.
When you encounter an unfamiliar recess, identify the drive before reaching for the nearest bit that seems to fit. Similar-looking teeth do not guarantee the correct engagement.
A quick bit-matching checklist
- Identify the drive shape before choosing a bit.
- Match the size, including metric versus imperial hex sizes.
- Check for a security pin when working with Torx.
- Keep Phillips and Pozidriv separate.
- Recheck the fit if the bit slips or does not seat properly.
There is no single best bit for every project. My main takeaway is simple: the best bit is the one that fits the screw correctly.
Watch the screwdriver-bit guide
What is your favorite bit, and which one has caused you the most frustration? Let us know in the comments.