Heavier instruments for toenails: wide-jaw clippers, strong nippers and files that survive a thick nail. Same steel and the same hand-set edges as the manicure line, sized for the load.
A toenail is several times deeper than a fingernail and much less forgiving. An ordinary clipper has a narrow curved jaw and a short lever: meet a thick nail with it and the jaws spread under load before they close, so the plate is crushed and folded rather than cut. Buying a sharper version of the same shape does not fix it.
A straight jaw fifteen millimetres or wider, so it crosses the nail in fewer bites and does not curve into the corner. A long handle, because cutting force comes from leverage rather than sharpness. And blades that close along their whole length — hold the instrument to a window and shut it slowly; daylight at the ends is where a thick nail will tear.
For a genuinely thick nail, a nipper — plier-shaped, two handles, a spring — beats a lever clipper. It delivers several times the force and lets you see the cutting line, which a clipper hides under its own body. A heavy clipper with a wide straight jaw is the easier instrument to hold and enough for a nail that is firm but not extreme. The method matters as much as the tool: how to cut thick toenails without splitting them.
Where grip strength or reach is the limit, the instrument matters more, not less: long handles and a spring that opens the jaws on its own reduce the work to a squeeze. This is the case where paying for a forged instrument is most obviously worth it — the effort saved is felt every time.
It is caused by how the nail was cut, not by the nail being hard, and cutting deeper into the corner makes it worse rather than better. What each of the specialised instruments actually does — and where the line is between care and a job for a podiatrist — is set out in ingrown toenail tools.
Leverage and jaw width. Toenails are thicker and harder than fingernails, and a light instrument flexes instead of cutting. Pedicure clippers and nippers are built heavier for exactly that load.
A nipper. It cuts in short controlled bites along the nail instead of trying to take it in one pass, which is what splits a thick nail rather than trimming it.
These are grooming instruments, not medical devices. If you have diabetes or any circulation or nerve condition of the foot, ask a podiatrist before trimming your own nails.
Dry the blades and the joint after every use and put the instrument back in its case. A drop of oil in the pivot once a month keeps the action smooth.