How to sharpen an engineer’s scraper

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Sharpening a HSS engineer’s scraper

Equipment you will need:

• Felt-tip pen –  this is used to mark the cutting edge of the scraper in order to check you have evenly sharpened the cutting surface and maintained the original cutting angle.

• Bench-mounted grinder with an aluminium oxide grinding wheel

Step 1 – Set angle of grinding platform

The first thing to do is set the angle and position of the grinding wheel platform. The platform should be close to the grinding wheel and set at the correct angle to maintain the original cutting angle of the scraper.

Step 2 – Colour scraper tip

Colour the cutting edge of the scraper with a felt tip pen. This will allow you to check you have maintained the correct angle along the whole length of the cutting edge whilst grinding.

The felt tip ink should be evenly removed along the cutting edge if you have maintained the correct angle.

Step 3 – Sharpen scraper on grinding wheel

Turn the grinding disc on and pass the whole of the scraper’s cutting edge over the grinding wheel, being careful to maintain the original cutting angle on the scraper.

Sharpening a carbide engineer’s scraper

Curved and triangular scrapers

All scrapers can be sharpened using a bench-mounted grinder with the correct grinding wheel. However, maintaining the original cutting angle on curved and triangular scrapers may be harder as the length of the cutting edge is greater. Because of this, some people prefer to sharpen these scrapers by hand, using an oil or whetstone for HSS scrapers and a diamond sharpening stone for carbide scrapers.

Sharpening a curved HSS blade with a whetstone

Equipment you will need:

• Aluminium oxide whetstone to sharpen the scraper

• Felt tip pen – this is used to mark the cutting edge of the scraper in order to check you have evenly sharpened the cutting surface and maintained the original cutting angle.

Step 1 – Soak whetstone

Soak the whetstone in water for 10-15 minutes so that it becomes saturated.

Step 2 – Highlight cutting face

Colour the cutting face of the scraper with the felt tip pen.

Step 3 – Rest scraper on whetstone

Start at one end of the whetstone with the tip of the scraper resting in contact with the surface of the whetstone.

Step 4 – Sharpen scraper

Push the scraper forward across the surface of the whetstone, tilting it back as you go, so that the whole of the scraping edge passes over the surface of the whetstone.

Step 5 – Check for even sharpening

Check that the felt tip pen on the cutting edge has been evenly removed.

Repeat steps 2-4, altering how much you tilt the scraper as you push it so that you evenly remove the felt tip across the whole of the scraper cutting surface.

Can you also sharpen a carbide curved blade like this as well?

You cannot sharpen a carbide scraper with an oil or whetstone, but you can use the same technique with a diamond sharpening stone instead. Instead of soaking the diamond stone in water, you should coat its surface with a specialist honing oil.