A cutter that will not cut is usually doing exactly what it was built to do, in a job it was never specified for. Five checks, in the order worth doing them.
1 · Is it the size you think it is?
Markings wear off first. A cutter that has been in the drawer for a year may not be the size on the label, and a job set up for one diameter will not behave with another.
Check: measure it. Do not read it.
2 · Is the depth of cut greater than the plate?
If the cutter is shallower than the material, it will cut partway and stop, and it will feel exactly like a blunt cutter to the operator.
Check: plate thickness against the cutter’s stated depth of cut, with a tape rather than a guess.
3 · Does anybody actually know what the steel is?
This is the one that gets skipped. Plain high-speed steel in stainless or high-tensile will dull fast, and that is not a defect – it is the wrong grade for the material.
Weathered and hardened steel do the same thing. So does anything that has been flame-cut nearby, because the heat-affected edge is much harder than the parent plate.
Check: what the material certificate says, or failing that what the job is. If nobody knows, say so when you ask for advice – it is a normal answer.
4 · Is the cutter matched to the machine?
- Shank. Weldon 19.05 mm is the common standard but not the only one. A cutter that will not seat properly will not cut properly.
- Stroke. A deep cutter needs travel the machine may not have.
- Power and speed range. A large cutter on a small machine cannot be run at the right speed under the right feed.
- The magnet. If the base is not holding hard, the cutter chatters and the edge goes quickly.
Check: the machine’s plate and manual, against the cutter you are trying to use.
5 · How much force is going into it?
Both directions are a problem.
- Too much force overheats the teeth, dulls the cutter, and eventually stalls and damages the motor.
- Too little lets it rub instead of bite, which work-hardens the steel under the teeth. On stainless that finishes the cutter within a hole or two.
Check: is the feed steady and constant, with coolant reaching the teeth on every hole?
What to do if all five check out
Then it may genuinely be the cutter, and that is worth pursuing.
Keep it. Do not throw it away and do not grind it – the wear pattern is the evidence, and a worn cutter beside a fresh one of the same size tells an experienced eye a lot.
Photograph the teeth, note the material, the machine, the speed and roughly how many holes it did, and take the whole lot to your supplier.
The pattern worth noticing
- Keeps happening on one machine? The problem is the machine.
- Keeps happening with one operator? It is training.
- Started when a batch arrived? It may be the batch.
Three different fixes, and only one of them is a new cutter.
Send us the details before you send us the cutter
Diameter, depth of cut, plate thickness, steel, machine model and roughly how many holes it did. We can usually tell you which of the five it is without seeing it.
Email info@neweratools.com or call +65 6241 0908.