H7 tolerance. ±0.005 mm. Standard bore finishing.

Drilled holes: ±0.05–0.1 mm diameter tolerance, Ra 3.2 µm finish, potentially not perfectly straight. Reamed holes: ±0.005 mm tolerance, Ra 0.4 µm finish, improves straightness. For precision bearing press-fits (H7/p6 requires ±0.015 mm on hole + ±0.010 on shaft), drilling alone cannot achieve. Drill first to rough, then ream to final. Adds about 10 seconds per hole in production.

H7: standard precision, ±0.015 mm on 10 mm bore. Adequate for most bearing fits, dowel pins, general precision. H6: high precision, ±0.010 mm on 10 mm bore. For precision instrument bearings, tight tolerance assemblies. H8: loose precision, ±0.022 mm on 10 mm bore. For situations where exact fit doesn't matter. Default specification: H7 unless specific reason for tighter or looser.

Partially. Reamer follows the existing drilled hole — it cannot correct gross miss-location (more than 0.1 mm). Reaming corrects: diameter, roundness, surface finish. It does NOT correct: hole position, angular alignment, off-axis drift. For precision hole locations, use precision drilling or interpolation cutting first, then ream.

Through-holes: helical-flute reamers preferred, chip evacuation through the hole, higher cutting speeds possible. Blind holes: straight-flute reamers required (helical would pull chips back into reamer), slower cutting, more careful chip management. Blind holes also need relief at the bottom — typically undercut or larger undercut below the reamed depth to accommodate chip accumulation.

When drawings specify H7 or tighter tolerance on hole diameters: yes, automatically included. When drawings don't specify tolerance: standard CNC drilling (±0.05 mm) used unless we identify precision fits requiring reaming. Always explicit on quote. Reaming operation adds minimal cost — typically included within hole-making cycle time on production parts.

Below 2 mm diameter: specialty micro-reaming (0.5–2 mm range) requires precision tooling and slower cutting. Tolerances achievable: ±0.003 mm. For very small precision holes, micro-reaming is the finishing process of choice — drilling alone cannot maintain adequate tolerance at these small diameters. Cost higher per hole due to specialty tooling and careful handling.