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What is a file’s size?

What is a file’s size?

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Diagram to illustrate how length is measured on a file Length is the only size that you will see listed for a file. It is measured from the point to the end of the heel, and the tang is not included in the measurement.

When is a file’s length important?

Image of a selection of files of different lengths Usually, the length of a file won’t be important to the project you’re working on.
A DIYer filing the corner off a piece of metal to leave a smooth, rounded finish For example, if you were working on rounding the corners on the edges of a long piece of metal, it wouldn’t matter whether you used a 250mm (10″) file or a 200mm (8″) file.
Image of a DIYer using a very small file to round corners on a large piece of wood You could even use a 100m (4″) file. It would just take you longer to do the job!
Image of a DIYer thinking carefully about file size There are a few things to bear in mind when choosing which length of file to use.
Image of a file that is much too large to file the small components that fit inside a lock

Limited space

If you are working in a confined space, you will need to be able to get your file inside that space to use it. Choosing a 250mm (10″) file might be a problem if you’re trying to work on a small component from a lock, for example!

Image of the wonkee donkee saw file size guide

Sharpening a saw

If you’re choosing a file to sharpen a saw, there are some specific guidelines that you should follow.

For more information, see: How to sharpen a handsaw with a file: choosing the right files

Image of a large bastard cut file ready to be used to file a wheel


If you’re working on a large piece of material and you’re aiming for speed, the use of a bigger file is more likely to get you across the finish line in the desired amount of time.

A comparison of different sized grade 2 files to show that the teeth per inch are not consistent This is partly because the larger files have bigger surface areas, but also because larger files tend to be more coarse.

For more information, see: What is a file’s coarseness?

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