How to square up a block with precision

Hey Everyone, welcome back to Technique Tuesday.

Last week I talked about making and squaring up strip sets. This week my topic is about squaring up blocks.  Many times as we build our blocks they may be out just a bit or right on the correct size. It is not uncommon for blocks to be out a bit – if the ¼″ seam isn’t quite right or the cutting is off a bit then the block will either be a bit too big or a bit too small. If this is the case then we need to square them off so that they are all a uniform size.

In today’s post I am only dealing with squaring up blocks and trimming down blocks that turn out too big. Dealing with blocks that turn out too small is the subject of another post altogether!

When building blocks with blocks within the block they must all uniform size as well. An example of a block within a block is the Road to Oklahoma or Road to Heaven blocks I made a few weeks ago for Stash Blasting Wednesday. Each of these blocks are made up of 2 different blocks within the block.  It is important that these two blocks are the correct size and square in order for the finished block to be the correct size.

What tools are needed?

A cutting mat, rotary cutter and appropriate sized square ruler are the tools needed for the job.

If the block is small such as 6 ½″ or smaller than I suggest using a 6 ½″ square ruler.

For blocks 7 ½″ – 12 ½″ I suggest using a 12 ½″ ruler.

These two sizes will give you the best value for your money.  If you are making bigger blocks then a larger ruler will be needed such as a 16 ½″ or 20 ½″.

I have many different sized square rulers and each time I come home with a new ruler my husband says, “Really?You need another ruler? Really? REALLY?”. A great response to this is “And how many screwdrivers do you have?” [EDITOR’S NOTE: Interestingly the conversation never quite gets around to the fact that I could purchase an entire set of screwdrivers for the price of a single ruler!!!]

Squaring Up A Block

What follows are a few examples with different sized blocks and rulers but the principle is the same for all sized blocks whether the block is a pieced block, an HST, a quarter square triangle or one single piece of fabric.

To demonstrate the technique I will start with the single piece of fabric.

Note: the photos appear uneven and round due to the wide angle lens – I was unable to get square on shots without my reflection in the ruler – I assure you the blocks are square with straight cuts

Single Fabric Block – 19 ½″  square

I have a fat quarter that I want to square down to a 19 ½″ square.  First of all press the fat quarter and once pressed lay it out on the cutting mat.

Pressed fabric on cutting mat.

Pressed fabric on cutting mat.

For this demo I am using a 20 ½″ square ruler.

Place the ruler on top of the fabric. The diagonal line that goes through the middle of the ruler should be lined up with the bottom left hand corner of the fabric. This may or may not be at the 19 ½″ line – since it has not been squared off yet it will be larger. The diagonal line should run to the opposite top right corner.

Make sure there is a small amount of fabric all the way around if you don’t have a nice straight line along one edge.

Place ruler on top of fabric with diagonal line in bottom left corner

Place ruler on top of fabric with diagonal line in bottom left corner.

Trim off the excess fabric on the right hand side of the ruler and the top of the ruler.

Trim off the excess fabric around ruler

Trim off the excess fabric around ruler.

Remove the ruler and turn the block around so that the just squared off edge is now at the bottom left corner of the mat.  Place the ruler back on top of the block with the 19 ½″ vertical and horizontal lines lined up with the left bottom corner.  The diagonal line on the ruler will sit right in the corner.

Align ruler on squared up side of block with diagonal line in bottom left corner.

Align ruler on squared up side of block with diagonal line in bottom left corner.

Trim off the excess fabric on the right hand side of the ruler and the top.

Trim off excess fabric.

Trim off excess fabric.

The block is now a perfect 19 ½″ square.

Small –  4 ½″ block

Using a small ruler such as a 6 ½″ or 5 ½″ square repeat the same process above to square off this small block. Make sure to line up the diagonal line of the ruler from the bottom left corner to the top right corner.

Place ruler on 4 ½″ block with 4 ½″ lines on edge of block.

Place ruler on 4 ½″ block with 4 ½″ lines on edge of block.

As you can see there wasn’t much to trim off.

Very little to trim off.

Very little to trim off.

Medium –  8 ½″ block

Using a medium sized ruler such as a 12 ½″ square or possibly a 10 ½″ or 8 ½″ square repeat the same process again to ensure the block is 8 ½″ square.

Line up 8 ½″ lines of ruler with edge of block.

Line up 8 ½″ lines of ruler with edge of block.

Once again there was very little to trim off – just a bit at the top left corner.

Very little to trim off.

Very little to trim off.

Large –  16 ½″ block

Using a large sized ruler such as a 16 ½″ square or 20 ½″ square repeat the same process to square up the block to 16 ½″.

Line up 16 ½″ lines of ruler with edge of block.

Line up 16 ½″ lines of ruler with edge of block.

If the 4 – 8 ½″ blocks that make up this larger block were the correct size then there shouldn’t be much, if any, to trim off this block.

Precision sewing and cutting is the key to blocks being the correct size and squaring up is also very important to ensure that the quilt remains square throughout the piecing of the entire quilt top.

Happy Quilting!

Jen Transparent Signature

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