Honing Troubleshooting Tips
Oval Bores
Verify that the tool is correctly sized for the bore.
Ensure the honing stones are properly trued, ideally to the exact bore diameter.
For thin-walled parts, reduce cutting pressure. If the stone stops cutting at reduced pressure, use a softer stone.
For bores with cutouts or large cross-holes, utilize keyway-type tooling.
Bellmouth Bores
Properly true the stones to match the exact bore diameter.
Reduce stroke length and use a tool with shorter stones if available.
If the bore length is less than 50% of the stone length, reduce the stone length to 1.5 times the bore length.
If bellmouthing persists, continue shortening the stone or switch to a softer stone. Be cautious—overcorrection can cause barrel-shaped bores.
Barrelled Bores
True the stones accurately to the bore diameter.
Increase stroke length and, if possible, use a tool with longer stones.
If the issue persists, shorten the stone at both ends. Overcorrection can lead to bellmouthing.
Combined Bellmouth/Barrel Bores
Common in bores with multiple cross-holes, such as valve spools.
Reduce stone length while increasing stroke length.
If the problem persists, use a softer stone.
Rainbow Bores & Waviness
Use long-series tooling with stone length at least 1.5 times the bore length.
Correcting bent bores may introduce bellmouthing—address this after the bend is corrected.
Tapered Bores
Ensure stones are properly trued to the bore diameter.
In manual honing, frequently reverse the component.
In automatic honing, adjust the stroke position to allow more of the stone to pass through the tight end of the bore.
Taper in Blind Bores
True stones to the exact bore diameter and reduce stone length to 2/3 of the bore length.
If the bore lacks sufficient relief at the blind end, start with a short stone to hone the bottom.
Use stones with a hardened tip.
Ensure an adequate supply of honing fluid reaches the blind bore.
Bent Bores
Use the longest available stone length, ensuring it is at least 1.5 times the bore length.
Straightening the bore may cause bellmouthing—address this issue once the bore is corrected.