Log cabin log sizes in centimeters

by Kathy
(France)

Kathy writes...

Please can you help with the sizing of logs for a 30cm log cabin square.

I am looking for a design like you did for the 9-inch square, i.e. light triangle and dark triangle.

Many thanks.

Kathy

I am very new to this skill so a little nervous of it...

Julie replies...

Hi Kathy!

No need to be nervous...it's only thread and fabric...both of which you can replace. Just take a deep breath and let it go.

I can help, but I've got a small problem, but not insurmountable. I live in the US (about 30 miles south of Chicago) and do not have access to metric rotary cutting tools.

Actually, I'd been wondering about this very topic--how to communicate properly to anyone outside the US that is on the metric system. (That's pretty much the whole world except us and another couple of countries.) I'm still wondering how to do it.

But for your example, I can do it. That's because all the rotary cut shapes are either squares or rectangles. The seam allowance added is the same amount for both shapes.

What I've done is to create patterns for two different blocks—one is 30cm finished and the other 33cm finished.

I can work in finished sizes. Where I get stuck is that I don't know what measurement you use for a seam allowance—again because I'm not on the metric system and don't have those tools.

So-o-o-o-o, you will need to do a bit of work on your end. I've tried to make it easy. Promise!

First, what is the metric seam allowance that you use for patchwork?

Here it's a quarter inch.

By my calculations, that's 0.635 centimeters. I suspect that's not a fun number to work with so use what's correct in metric.

Next, multiply that by 2 because we add a seam allowance to both sides of each dimension of a rectangle or square, i.e. the length and the width.

Then in the charts below, you will need to add that 'seam allowance times 2' to each dimension. I've made the last column just for that purpose.

For example, Patch 2 in the first chart finishes at 3cm x 9cm. Add the number you calculated to each.

If, for example, your seam allowance is .5cm, then...

2 x .5cm = 1cm
Add 1cm to each dimension to get the cut size of...

4cm x 10cm
If your seam allowances are different than .5cm, you'll substitute whatever number that is.

Does that make sense???

The Log Cabin Block Designs

These are the two variations and their cutting charts. Below the second chart is a link to download and print a worksheet where you can add the seam allowances to the finished patch sizes. (You'll need Adobe installed to do that.)

Log Cabin Block 1: Larger center square

This block finishes at 30cm x 30cm. It has four rounds of logs.

CUTTING CHART for Log Cabin Quilt Block 1 – 30cm Finished
Patch	Fabric	Finished Patch Size in Centimeters	Add 2 x Seam Allowance to each dimension
Center	Center	6x6
1	Light	3x6
2	Light	3x9
3	Dark	3x9
4	Dark	3x12
5	Light	3x12
6	Light	3x15
7	Dark	3x15
8	Dark	3x18
9	Light	3x18
10	Light	3x21
11	Dark	3x21
12	Dark	3x24
13	Light	3x24
14	Light	3x27
15	Dark	3x27
16	Dark	3x30

Log Cabin Block 2: Small center square

This block finishes at 33cm x 33cm. It has five rounds of logs.

CUTTING CHART for Log Cabin Quilt Block 2 – 33cm Finished
Patch	Fabric	Finished Patch Size in Centimeters	Add 2 x Seam Allowance to each dimension
Center	Center	3x3
1	Light	3x3
2	Light	3x6
3	Dark	3x6
4	Dark	3x9
5	Light	3x9
6	Light	3x12
7	Dark	3x12
8	Dark	3x15
9	Light	3x15
10	Light	3x18
11	Dark	3x18
12	Dark	3x21
13	Light	3x21
14	Light	3x24
15	Dark	3x24
16	Dark	3x27
17	Light	3x27
18	Light	3x30
19	Dark	3x30
20	Dark	3x33

Click here to download your worksheets.

Kathy, I hope this helps. If you would be so kind, I'd love to know what the standard seam allowance is in metric. Are your rulers in metric?

If you'd share that in the 'Comments' link below, I'd be grateful!

Thank you!

Piecefully,

Julie Baird
Editor

PS For those of you looking to make a Log Cabin block and cutting in inches, refer to How to make a Log Cabin quilt block in 3 sizes.

This article was printed from Generations-Quilt-Patterns.com