What the left-hand corner does that the centre tooth cannot
On a WA380 class bucket the corner is where the geometry turns. The centre teeth meet the pile square, but the corner casting works against the side wall on every pass, takes the torsional load when the operator crowds one side, and wears on two faces instead of one. That is why it is a wider and heavier casting than the centre — 23.4 kg against 17.5 kg — and why it is handed.
423-70-13144 is the left-hand casting: the outer flank and the bolt bosses are laid out for the left side of the bucket as the operator sits in the cab facing the lip. Fit it on the right and the wear face turns inboard, the bolt holes no longer line up with the nose, and in most cases it will not seat at all. There is no such thing as "two corner teeth" on an order line — the corners are one left and one right.
Reading the number: 13144 against 13143
This is the mistake worth slowing down for. The Komatsu parts catalogue carries both 423-70-13144 (TOOTH, L.H.) and 423-70-13143 (TOOTH, CORNER L.H.) as left-hand corners for the same family of loaders, both printed at 23.4 kg. One digit separates them. On the WA350, WA400 and WA420 the catalogue lists both, so a machine plate and a tape measure will not decide which one is on the machine.
What we do instead, and what we ask buyers to do, is photograph the corner from the side with a rule laid against it, and photograph the number cast into the back of the tooth. The flank profile differs between the two castings; the cast number settles it. If the old tooth is already in the skip, the bolt-hole spacing on the nose usually still separates them, and we can measure that from a photo with a tape in frame.
Why the published weight runs from 22.7 to 25.3 kg
| Source | 423-70-13144 | What the row prints |
|---|---|---|
| Komatsu parts catalogue | 23.4 kg | TOOTH, L.H., scheme position 5, one per corner |
| BDI Wear Parts | 22.7 kg | WA380 / 450, BL and BR rows |
| SJ-GET | 23.6 kg | WA380 / 420 / 450; alloy steel, HRC 48–52, tensile 1400 N/mm² |
| Beneparts | 23.6 kg | WA380 / WA420 |
| HCE Parts | 24.0 kg | WA420-1/-3, WA470-1/-3; fastener column reads 4 |
| Komatsu aftermarket table | 25.3 kg | Printed on a WA470-5 row together with 423-70-13154 |
2.6 kg is a casting difference, not a data error: pattern allowances, riser placement and how much the foundry machines off the socket all move a corner tooth by a kilo or two. It matters on freight — twenty corners at 22.7 kg are 454 kg, at 25.3 kg they are 506 kg, which is the difference between one freight band and the next. We weigh each lot and put the weighed figure on the packing list, so the number on the airway bill is the number on the pallet.
Variants of the same corner position
Komatsu's consumable tooth list prints three alternates for this corner on the same machines, and they are different parts rather than price options. The lime-bucket corner is 423-842-1120 left against 423-842-1110 centre and 423-842-1130 right, for cement and lime work where the wear is fine abrasion rather than impact. The long-life corner is 423-T74-1120 left. Both are printed for WA380-5 through -8, WA430-5/-6 and WA480-5/-6/-8 as well as the WA470 rows the standard tooth covers.
There is also a hybrid numbering, ZZD4237013144 for this casting, which denotes an aftermarket tooth with a hardfacing or carburising process applied. Komatsu's own note states the genuine numbers are not hybrid-processed, so if a customer has been buying ZZD numbers and wants the same again, the correct answer is the hybrid part, not a standard 423-70-13144 that will wear out sooner.
Fitting and ordering
The corner is a bolt-on part: four fasteners through the side, no pin, no retainer, no shimming. Two things go wrong on a corner change. The first is a worn nose — a bolted monoblock cannot be drawn down onto a base that has lost its face, so a corner that rattles after fitting usually means the nose is done, not the tooth. The second is missing fasteners, so we quote bolts and nuts on the same line as the castings. The exact bolt number on a corner should be confirmed against the machine's parts book, which is also what Komatsu's consumable list tells the buyer to do.
To quote a set we need four things: the number off the old tooth, a side photo of the corner, the machine model with serial number if it is a WA380-5 or later, and the quantity by position. Corner sets are quoted as one left plus one right plus whatever centres the lip takes — not as a single number at a round quantity. The full set for a WA380 is written out in our WA380 tooth guide, and the handed-pair question is covered in more detail in the corner teeth guide.
FAQ
Q: What is the Komatsu 423-70-13144?
A: The left-hand corner tooth of the 423 series bolted monoblock bucket, named TOOTH, L.H. in the parts catalogue and printed at 23.4 kg. One alloy-steel casting, four bolts, no pin.
Q: Which machines take it?
A: Komatsu's consumable list prints it for WA380-5 through -8, WA430-5/-6, WA450-1/-3, WA470-5 through -8 and WA480-5/-6/-8. The parts catalogue model list adds WA350, WA380Z, WA400, WA420 and the 538, 542, 545 and WF450 loaders.
Q: How do I tell it from 423-70-13143?
A: The cast number on the tooth. Both are left-hand corners at 23.4 kg in the catalogue and both are listed for the WA350, WA400 and WA420, so weight and model plate do not settle it.
Q: How many bolts?
A: Four per corner in the catalogue table we read, against three on the centre tooth. We confirm the bolt and nut numbers against the parts book before shipping.
Sources
Part names, weights and machine coverage come from the Komatsu parts catalogue rows for 423-70-13143, 423-70-13144 and 423-70-13154 and from Komatsu's consumable tooth and edge parts list, both read in October 2026, together with aftermarket listings from BDI Wear Parts, HCE Parts, SJ-GET, Beneparts and a Komatsu aftermarket table printing 25.3 kg. Figures are reproduced as printed; where catalogues disagree, all values are shown and none is averaged. Komatsu and the referenced part numbers belong to their respective owners and appear here for fitment reference only. No price is published — these are quotation items.