| Angle control | Check whether the guide is fixed at a right angle or has an adjustable angle, and confirm the adjustment range and locking method in its specifications. | The guide determines the drill’s orientation relative to the work surface. A loose or poorly locked setting can let the bit wander. | Choose a fixed 90-degree guide for repeated perpendicular holes. For angled work, select an adjustable guide with clear angle markings and a secure lock; verify the stated range before purchase. |
| Drilling depth | Look for a depth stop, depth collar, or another repeatable way to limit bit travel. Check the usable depth range and how the stop is secured. | A positive stop helps produce consistent hole depths and reduces the risk of drilling through the workpiece. | For repeated holes, prioritize an adjustable stop that can be tightened securely. Set the depth using the actual bit and workpiece, and allow for the bit’s point when measuring. |
| Alignment and registration | Inspect the guide’s reference faces, centering features, edge stops, fences, or bushings. Confirm how the guide registers against the workpiece. | Reliable registration helps keep holes centered and consistently positioned, especially when drilling into an edge or narrow surface. | Choose broad, square reference surfaces for edge drilling. For repeatable hole positions, look for a fence or stop that can be set and locked against a known edge. |
| Workpiece stability | Check whether the guide has a clamp, a clamping point, or a stable base that can be held firmly against the material. | Movement during drilling can affect angle, position, and hole quality. Small or narrow pieces are particularly difficult to hold by hand. | Prefer a guide that can be clamped or paired with a suitable clamp. Secure the workpiece independently and keep the guide’s reference face in full contact. |
| Drill and bit compatibility | Verify the supported drill or bit-shank diameter, guide-bushing size, and whether the guide accommodates the drill being used. | A poor fit can allow excess play or prevent the drill from being held correctly. | Compare the guide’s stated compatibility with the tool and bit dimensions. Do not assume that every guide fits every drill or bit size. |
| Visibility and setup | Check whether adjustment marks are readable and whether the bit, depth stop, and workpiece reference remain visible during setup. | Clear visibility makes it easier to confirm the drilling position and settings before starting. | Choose controls that are easy to set and inspect. Before drilling, verify the angle, depth, and alignment with the drill stopped. |
| Repeatability | Assess whether angle, depth, and position settings can be locked and returned to consistently. | Repeatable controls are useful when several holes need the same orientation and depth. | For batch work, prioritize positive locks and adjustable stops. Test the setup on scrap material before drilling the finished workpiece. |