Grading Ruler & French Curves

Every professional pattern maker needs an accurate ruler to do their work in a better way. The best type ruler for pattern making should be with strong plastic including grid line in the whole ruler, making it easily to measuring and mark seam allowance. 50 cm plastic pattern grading ruler, like the picture shows from Kearing, is great to mark seam allowance by using its straight edges and you can also use it to get parallel lines. We also call it the Grading Ruler as it is also an ideal tool for sewing grading patterns.

When we draw seam seam allowance lines, just directly use the straight grading ruler even when around curves. It is conveniently to line up the grid of the straight ruler to the mm and make a small line marking, and we can draw dashed lines when rotating the ruler along the curves. It would be helpful to give an accurate guide for drawing perfect curve lines with french curve ruler. The picture just shows our Kearing brand #8001 Grading Ruler and #1203S French Curves, you can also check other types pattern making ruler and french curves to test out the best one for you.

Here let’s see how to use the grading ruler and french curve to mark the seam allowance:


We can use the pattern grading ruler to trace along the straight lines and draw parallel lines at our desired width of seam allowance, as it shows on picture we are setting it as 1 CM, you can change it either way and just follow your own style to finish your seams.


When drawing along the curve of armhole and necklines, just use the straight ruler to draw small dashed guidelines.


The advantage of this grading ruler is we can use it for marking wider seam and hem allowances as it is a full width ruler. Now we can use the french curve to connect those dashed guidelines.


Remember to check the seam allowance corners, it is one of the most important step. The easiest way to make sure their corners are perfect or not is just directly review it with your eyes and see whether it is with a nice right angled corner. If not, you have to draw seam allowance lines again!

Please also keep in mind to check how wider seam allowances will sit when sewn. You’d better to check and fold out the value of wider seam and hem allowance to make sure you are having enough fabric. If do it in a wrong way, the seam allowance will angle inwards and sestrict the waist. If you are doing it in a correct version, congratulations! The hem allowance will fold up and perfectly sit inside the body of the fabric. You will complete the project smoothly!

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KEARING was born in 1995, from the passion and tenacity of its founder, Jason Zhao, who started its journey from a remote country village in China …

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