A good hole starts with the correct bit
Diameter alone is not enough: cutting geometry, material, shank and substrate determine performance. A metal twist drill is not a masonry bit, and a percussion bit will not make a clean sheet-metal hole.
Bosch Professional lists multi-material bits separately; this does not make every bit universal. Follow the specific tool and accessory limits.
1. Identify the substrate
Confirm whether the surface hides steel, aluminium, timber, concrete, brick or tile. Check drawings and scan for services before drilling walls.
Solid concrete, hollow masonry, thin sheet and thick steel require different modes. Test an inconspicuous area where appropriate.
2. Secure metal before drilling
Suitable HSS twist drills cover many steel jobs; harder or repetitive work needs a manufacturer-selected grade, coating and geometry. Larger diameters generally require lower speed.
Clamp the work. A grabbing drill can spin loose sheet. Use a centre mark, support the exit and deburr both sides.
3. Match masonry bit and holder
Cylindrical masonry bits, SDS-plus and SDS-max shanks need compatible holders. Never force one system into another.
Confirm the diameter against the anchor instructions. Stop if reinforcement is encountered and obtain engineering approval before altering it.
4. Choose wood geometry by task
Brad-point, auger, Forstner and hole-saw tools serve different depths and finishes. Stay within tool and bit limits.
Support the exit to reduce tear-out, check for hidden fasteners and control dust from treated timber.
5. Check the shank and chuck
Round, hex and SDS shanks lock differently. Seat the bit fully, tighten the chuck evenly and remove its key before starting.
A quick hex holder or impact wrench is not a universal drill. Stop if the bit runs out or wobbles.
6. Balance speed, impact and pressure
Large bits usually need lower speed. Excess speed overheats metal bits or burns wood; excess pressure can jam them.
Use impact only with compatible materials and bits. Withdraw periodically from deep holes to clear chips without touching rotating parts.
7. Control depth and clean the hole
Anchors require the specified diameter, depth and cleaning. Dust may prevent full seating, and cleaning sequences differ by system.
Account for working length and debris at the bottom. A larger fastener does not automatically repair a poor hole.
8. Inspect safety and condition
OSHA stresses correct accessories, guards and personal protection. Isolate power or remove the battery before changing bits.
Discard cracked, bent, blunt or overheated bits. State material, diameters, depth, shank, tool model and quantity when ordering.