how-to-sharpen-bolt-cutters

     How to sharpen bolt cutters

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Bolt cutters with blades that have been damaged through cutting hardened steel After using your bolt cutters for a while, you may notice that the blades have small dents and chips in them, which can often occur when they are used to cut through hardened steel. You can solve this problem by sharpening them.
Equipment needed for sharpening bolt cutters: a vice, an angle grinder, a mill file, a firm bristle brush, a cleaning cloth and a small bottle of lubrication oil. You will need:-

  • A firm brush
  • A clean cloth
  • A vice (if you have one)
  • A mill file or an angle grinder
  • Oil or grease
Example of a mill file, which can be used to sharpen bolt cutters

What is a mill file?

A mill file is a tool with abrasive teeth that is designed to sharpen metal blades.

For more information on mill files and how to use them, see: Mill Files

Example of an angle grinder, which can be used to sharpen bolt cutters

What is an angle grinder?

An angle grinder is a tool with an abrasive disc that is spun by an electric motor.

For more information on angle grinders and how to use them, see: Angle grinders.

Example of a metal grinding disc, which should be fitted to an angle grinder to sharpen bolt cutters If you are using an angle grinder to sharpen your bolt cutters, you will need to fit it with a metal grinding disc.

For more information, see: Angle grinders.

Hand holding a wiping cloth, illustrating that bolt cutter blades need to be well wiped before being sharpened

Step 1 – Check tool is clean

Make sure, before you sharpen the blades of your bolt cutters, that they are free from debris and dirt. Brush the jaws, then wipe them down with a clean cloth.

Wide open jaws of a pair of red, long-handled bolt cutters.

Step 2 – Open blades

Open the jaws of the bolt cutters as wide as possible.

Wide open jaws of a pair of bolt cutters being held firmly in a vice ready for sharpening

Step 3 – Grip jaws firmly

The best way to hold the tool head steady is to secure it in a vice. If you are using a file to do the sharpening, however, you could just grip the bolt cutters between your knees. When you have finished one blade, loosen the vice, turn over the jaws and reclamp to tackle the next one.

DIYer sharpening bolt cutter blades with an angle grinder

Step 4 – File at an angle…

The blades on bolt cutters, like scissors, are bevelled at the edge. That is to say, they are angled (at a degree of 20-30 degrees) to form a sharp ridge. When you file or grind your blade it is necessary to follow this angle.

Replacement jaws for bolt cutters with blade edges correctly rounded off.

Step 5 – … but not too sharp!

Do not grind or file your bolt cutter blades to a very sharp edge. They should have a rounded-off ridge, as they do not need to “slice” through material, but rather force it apart. Overly sharp edges diminish that blunt separating force and leave the blade edges vulnerable to buckling and denting.

Brush with handle, to be used for cleaning up bolt cutter blade filings after sharpening

Step 6 – Clean up

Brush and then wipe down your blades with the cloth when you have finished filing, to remove the fine metal particles which will have been created.

Small bottle of multi-purpose oil to be used for wiping on sharpened bolt cutter blades

Step 7 – Apply oil

Finally, take the cloth again and wipe down the length of the blades with a generous coating of oil. This will help to keep them free from rust.