WS39 casing tooth
JM cutter tooth
B47K22 bullet toothThe review of this 1,200 mm barrel identified which of ten roller-bit positions needed prompt replacement and which surrounding parts also needed attention. The operator reported approximately 40–50 m of drilling, including boulders. Numbered photographs define the proposed scope.
The distance is the operator’s account at the 15 April 2023 visit. Photos document the condition at that inspection; a full individual-cutter replacement history was not available.
Select replacements by position and condition.
The inner and outer positions below come from the same inspection. Compare the carbide inserts and the cone steel supporting them; both informed the replacement decision.
Considered usable at the visit
Recommended for replacement
The field assessment linked the outer insert loss mainly to worn cone steel providing less support. This was the inspection’s working explanation; the photographs establish condition at that visit.
See the assessment for all ten positions
A position-by-position replacement decision
| Positions | Condition recorded | Decision at that visit |
|---|---|---|
| Outer 1 / 3 / 4 | Cone-body wear had reduced insert support; inserts had been lost. | Prompt replacement recommended. |
| Inner 4 | Some lost inserts; remaining steel support needed attention. | Included among seven considered usable at the visit, with continued deterioration risk. |
| Inner 5 | Some fractured inserts. | Included in that same seven-position group; keep the fracture condition with the position record. |
| Inner 1 / 2 / 3, outer 2 / 5 | Considered usable in the inspection, within a set with severe overall cone-body wear. | Reassess together with the replacement plan and cuttings-removal condition. |
The replacement plan also needed the worn guide strips, scraper arrangement and operating load reviewed.
Carry each position number into the parts list.
Outer 3, together with outer 1 and 4, formed the proposed replacement group. Its label connects the empty insert seats and worn cone steel to the parts list. This is another position at the same visit, not a later wear stage of outer 1.
THE SURROUNDING TOOL
Include the guides in the repair scope.
The external cuttings guides had worn close to the shell. The original tool had no dedicated scraper position; a scraper was added later.
All five inner positions and outer 2 and 5 were considered usable at that visit, despite severe overall cone-body wear.
Inner 4 had some lost inserts and inner 5 had fractured inserts, so those conditions also needed to remain visible in the replacement plan.
When the cutting ring also needs repair →
Review operation before fitting the replacement group.
The field review proposed checking applied load, cuttings transfer around the worn guides, and fluid condition. Its working explanation was that rapid cone-steel loss had reduced insert support. Those operating conditions therefore belonged alongside the affected positions in the replacement review.
No measured drilling-pressure value, head speed or depth-by-depth log was recorded at this inspection. The 40–50 m remains the operator’s total; the file does not confirm implementation or results of the proposed operating changes.
Turn the inspection into a defined supply scope.
With the positions identified, match the connection. Replacing an individual roller bit means replacing the cutter assembly at that position; the leg, holder or bolted connection defines which parts to include.
Mounting references below are DRILLNOVA product renderings, separate from the field photographs above.
MH-3 / WELD-ON
Leg and cutting ring
Show the leg, old opening and surrounding weld area. Check the replacement position and working height against the selected drawing.
- Agree the supply
- Roller-bit assembly; identify any separate ring-repair work.
MH-3C / HOLDER-MOUNTED
Cutter and holder
MH-3C combines mechanical retention with welding. Show the holder opening and fixing details; confirm the holder condition and the selected weld arrangement.
- Agree the supply
- Replacement cutter only, or cutter with holder and required retaining parts.
MH-3B / BOLT-MOUNTED
Crossbar and fixing parts
Show the crossbar, two bolts and locknuts. Match the fixing arrangement and mounting dimensions before selecting parts.
- Agree the supply
- Roller bit and an explicit list of the crossbar, bolts and nuts required.
A similar cone diameter does not confirm an interchangeable mounting. If the model is unknown, start with photos of the existing connection.
Read the service context and limits of this inspection
What was on the tool, and how far had it worked?
Service record and inspection scope
| Item | Recorded information |
|---|---|
| Core-barrel diameter | 1,200 mm |
| Roller-bit positions | 10: five inner and five outer |
| Drilling distance reported by the operator | Approximately 40–50 m, including boulder drilling |
| Condition at the inspection | Slower advance; severe cone-body wear overall |
| Immediate replacement group | Outer 1, outer 3 and outer 4 |
The operator’s approximate distance is service context. The missing serial-by-serial replacement log prevents treating it as an unchanged-set lifetime.
The inspection defines a proposed replacement scope; the later repair and service outcome were not documented.