Troubleshooting

Oval Bores

Ensure the tool is the correct size for the bore to be honed. Thoroughly true in the stones, preferably to the exact bore diameter. If the part to be honed is thin walled, reduce the cutting pressure. If the stone stops cutting at reduced pressure, use a softer stone. For bores containing cut outs, large cross holes etc. use keyway type tooling.

Bellmouth Bores

Thoroughly true in the stones, preferably to the exact bore diameter. Reduce the stroke length and use tool with shorter stone length if available. If the bore length is less than 50% of the stone length reduce the stone length to 1½ times the bore length. If bell mouth persists continue to shorten stone or use a softer stone. Over correction will cause barreling.

Barrelled Bores

Thoroughly true in the stones, preferably to the exact bore diameter. Increase stroke length and use tool with longer stone length if available. If barreling persists shorten stone at both ends. Over correction will cause bell mouthing.

Combined Bellmouth / Barrel Bores

Typical in bores containing many cross holes, e.g. valve spool. Shorten stone length AND increase stroke length. If problem persists use softer stone.

Rainbow Bores (& Waviness)

Use long series tooling. Stone length should be at least 1 1/2 times the bore length. Correction of bent bores may result in bellmouthing. When bend has been corrected any bellmouthing can be corrected as described above.

Tapered Bores

Thoroughly true in the stones, preferably to the exact bore diameter. When honing manually reverse the component frequently. When honing automatically adjust stroke position to allow more stone to pass through the tight end of the bore.

Taper in Blind Bores

Thoroughly true in the stones, preferably to the exact bore diameter and reduce the stone length to 2/3 bore length. If the bore has insufficient or no relief at the blind end use short stone first to hone bottom of the bore. Use stone with hard tip. Ensure adequate supply of honing to blind bore.

Bent Bores

Use longest stone length available. Stone length should be at least 1½ times bore length. Correction of bent bores may result in bell mouthing. When bend has been corrected any bell mouth can be corrected as described above.

Stone Gazed

Stone does not cut
Open surface of stone with dressing stick
Increase stroking speed
Reduce rotation speed
Increase pressure
Use softer stone

Slow Stock Removal

If slow stock removal is not the result of stone glazed or loaded
Increase rotation speed
Increase pressure
Use softer stone
Use coarser stone

Pick Up

Reduce pressure
Reduce rotation speed
Use softer stone
Use finer stone
Change HS type mandrel to bronze or PT type
Ensure good flow of honing fluid
Check quality of honing fluid

Finish Too Fine

Open surface of stone with dressing stick
Increase stroking speed
Reduce rotation speed
Increase pressure
Use coarser stone
Use softer stone

Stone Loaded

Stone surface becomes clogged with material
Clean stone surface with dressing stick
Increase stroking speed
Use softer stone
Use coarser stone

Excessive Stone Wear

Reduce pressure
Increase rotation speed
Use harder stone
Use finer stone

Finish Too Rough

Thoroughly dress stone and shoe preferably to exact bore diameter
Increase rotation speed
Reduce pressure
Use finer stone
Check quality of honing fluid

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Superior Type Troubleshooting

A Common Honing Problem

What is overhooking?

Overhooking occurs when the bayonet of the mandrel wears and/ or the hook pin in the spindle that receives the bayonet wears. Overhooking of the mandrel throws torque onto the stone wires, which provides the chance for the stone wire to pull off the stone shoe at the weld joint, usually tearing a section of the stone wire, which is not designed to carry torque.

A check for this condition is easily made without inserting stone or turning on the machine. In the illustration below, the overhooking condition is show.

Superior Type

One more additional check – The hardened mandrel pilot bushing in the spindle will, in time, wear and need to be replaced. If these features are right, you will hone more easily and get the results you desire. If you have any questions please give Tennessee Abrasive a call.

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