Honing Machine

Overview

A honing machine brings a drilled or bored hole to its final size, roundness and surface finish using bonded-abrasive stones rather than a single cutting edge. The stones cover a wide arc of the bore and float to follow it, so honing corrects the taper, barrelling and out-of-roundness that turning or boring leaves behind, and lays down a controlled cross-hatch finish, the diamond pattern you see inside an engine cylinder, which holds oil and beds in rings. It removes only microns, but does so to tolerances a few times tighter than the operations before it.

This is a vertical machine. The bore points up, fixtured under the spindle on a Workholding Fixture that floats laterally so the tool, not the clamp, sets the bore axis. The Hone Spindle carries the Honing Tool and Abrasive Stones on a self-aligning driver, and two motions combine: the Rotation Drive spins the tool while the Reciprocating Drive strokes it up and down the column. Their ratio sets the cross-hatch angle, the signature of a honed bore.

How it works

Cutting pressure comes from the Stone Expansion Mechanism mechanism. Down the centre of the hollow spindle a feed rod pushes a cone that wedges the Stone Shoe-mounted stones outward against the bore wall; a coil spring pulls them back when the rod retracts. The harder the stones press, the faster they cut, so the feed actuator meters that pressure precisely while a sensor watches either feed force or the growing bore size.

The Control runs the cycle. It spins the Rotation Drive, strokes the head with controlled overrun past each end so the stones wear evenly, and advances the Stone Expansion Mechanism until the bore reaches size. Throughout, the Coolant System floods the hole to flush abrasive grit and metal fines and to keep the stones cutting cool. When the in-process gauge reads the target diameter, the CNC Controller retracts the stones and lifts the tool, and the bore comes out round, straight and cross-hatched to print.