A DTH bit is a consumable, but it shouldn't disappear on you. If your bits are wearing out noticeably faster than they should — losing gauge, cracking buttons, or drilling undersized holes — the cause is usually one of a handful of fixable problems. Here are six of the most common, and what to do about each.
1. Not enough flushing air
Compressed air carries cuttings up and out of the hole. When there isn't enough of it, cuttings stay in the hole and get re-ground under the bit — sandblasting the carbide and steel. Symptom: rapid gauge and face wear, slow penetration, cuttings that look over-ground. Fix: confirm your compressor delivers the volume and pressure the hammer needs, and check for a worn hammer that's leaking air.
2. Letting the buttons go too long between regrinds
As tungsten carbide buttons wear, they develop flats — often called "wear flats" or "snakeskin." Drilling on flattened buttons dramatically increases the energy needed to break rock, accelerates carbide loss, and can lead to button cracking or loss. Fix: regrind on a schedule. A common rule of thumb is to regrind once a wear flat reaches about one-third of the button's diameter. Regular regrinding is the single biggest lever on bit life.
3. The wrong bit for the formation
Button shape and carbide grade are matched to rock type. Run an aggressive, soft-formation bit in hard abrasive rock and the buttons wear or break; run a hard-formation bit in soft ground and you leave penetration rate on the table. Fix: match button geometry and carbide grade to your formation — and re-evaluate whenever you move to a new site or hit a different rock type.
4. Feed and rotation out of balance
Too much feed pressure for the penetration you're actually getting overloads the buttons and causes breakage. Rotation speed that doesn't match penetration rate causes uneven, one-sided wear. Fix: tune feed to the formation, and set rotation so the bit indexes to fresh rock on each blow rather than re-striking the same grooves.
5. A worn or under-lubricated hammer
The bit can only be as effective as the hammer driving it. A worn hammer delivers less impact energy, so the bit spends more time grinding on rock to make the same hole — and more time on rock means more wear. Fix: keep the hammer properly lubricated, service it on schedule, and rebuild it before internal wear starts robbing energy.
6. Drilling broken ground without adjusting technique
Fractured, broken, or interbedded formations load the gauge buttons unevenly and shock the bit, which breaks peripheral buttons and knocks holes off line. Fix: collar slowly, ease through voids and seams, and consider a flat-face bit designed to hold straight in broken ground.
One more habit: retire bits before they drill undersized
Gauge (outer) buttons set your hole diameter. Once they wear down, the bit drills a hole that's too small — and the next, fresh bit binds when it follows. Pull a bit from service before it starts cutting undersized holes, not after.
Keep your bits — and your schedule — on track
International Driller's Supply carries DTH bits, hammers, regrinding supplies, and the expertise to help you match tooling to your formation. If your bits are wearing faster than they should, we can help you find out why. Call 615-255-1791 or email sales@internationaldrillerssupply.com.