Rotary cutting Part 8

This is the final instalment of our rotary cutting series and looks at cutting the triangles needed for the Peaky and Spike unit.

unitThe centre triangle is an isoceles triangle – its height and base are the same length, so you can cut it from a square. The triangles at the edges (long, or skinny triangles) are half as wide as their length and are thus cut from rectangles.

The square for the centre triangle should be cut 1 inch larger than the finished unit. If you want to cut more than one triangles then cut a strip 1 inch wider than the finished unit – for a 3 inch unit, cut a 4 inch strip.

Mark 4 inch squares along the length of the strip. Make sure you mark on the wrong side of the fabric as these marks may be visible later. The marks in the photos are heavy and thick so they show up, yours should be much lighter.

measure and mark squaresOnce all the squares are marked you need to mark the midway points between the squares – in this example that would be at 2 inches.

mark halfway pointsThese marks could be much shorter than the ‘square’ marks, or in a different colour.

all marking doneMake the first cut by placing the ruler on the bottom of one ‘square’ mark and the next midway mark on the opposite side of the strip.

first cutAnd cut along the edge of the ruler. No angles to measure here as isoceles triangles don’t have nice ‘easy to measure’ angles.

first cut doneTo cut the triangle place the ruler at the bottom of the next ‘square’ mark and at the tip of the cut you just made (on the midway mark).

second cutand cut.

first triangleCut the next triangle by placing the ruler at the base of the ‘square’ mark and the top of the next midway mark – (and you can see why you mark on the wrong side of the strip)

second triangle doneContinue along the strip until you have cut the number of triangles you need. Don’t forget that you can keep the strip folded and cut two triangles at a time – its much quicker.

Now its time for the skinny triangles. The rectangles should be 1 + 1/4 inches longer than the unit and 5/8 inch wider than half the width of the unit. So our 3 inch finished size units needs rectangles that are 4 + 1/4 inches x 3/2 + 5/8  (i.e. 2 +1/8) inches. For each unit you need two mirror image triangles – this means you need to cut two rectangles to start with. It is easier if you keep the strip folded and cut the rectangles in pairs.

Cut the paired rectangles in half across one diagonal.

cut rectangles in half

rectangles cutThis will give you two sets of mirror image triangles

mirror imagesThese can then be paired with the larger triangles –

pair with trianglespaired ready to stitchready to stitch together.

 

 

 

Rotary cutting Part 7

Having done the 60 degree triangles and diamonds last time we probably ought to look at 45 degree diamonds – these are the ones used in 8-pointed and Lone Stars.

eight pointed starLone StarAs for the 60 degree diamonds – first cut a strip the width of the diamond plus 1/2 inch for seam allowance. Then trim the ends of the strip to 45 degrees using the 45 degree line on the ruler. Keep the strip folded in two as you will need half your diamonds cut left to right and half right to left – keeping the strip folded cuts these two at the same time without you having to worry about it. If using two colours for your diamonds. open the strips out and place them right (or wrong) sides together and then cut.

trim to 45 degsend trimmedNow line the 45 degree line up along one long edge, measure the same width as the strip along to cut the diamond. These are 2 + 1/2 inch diamonds.

measure diamondand cut the first diamond

cut diamondJust as before, slide the ruler along to cut more diamonds.

continueYou will need 8 (obviously) for an 8-pointed star – as you are cutting two at a time you only need to cut four pairs. Each cut pair makes a unit –

use for Lone StarAnd that’s it. Next time we’ll look at cutting the triangles you need for the unit often known as Peaky and Spike.

unit

 

 

 

 

Rotary cutting Part 6

Those lines marked with numbers that go across your ruler are for cutting 60 degree (or 30 degree) angles – especially equilateral (60 degree) triangles and diamonds. These are used to make hexagon shapes.

All rulers have these lines – some have more than others and some are clearer than others.

rulers and degree linesFirst cut your strip. For equilateral triangles cut the strip 3/4 (three quarters) inch wider than the required height of the triangle. So if the finished size of the triangle is 3 inches, cut a 3 + 3/4 inch wide strip.

Trim one end of the strip to a 60 degree angle. Which end depends on whether you are right or left handed among other things – dance around the strip and cutting mat until you decide which end feels most comfortable. Find the 60 degree line on the ruler and place it on one of the long sides of the strip –

60 degree linethen trim off the unwanted triangle.

trim end to 60 degsNow turn the ruler so it faces the other way, place a 60 degree line on a long side of the strip and the edge of the ruler against the tip of the first cut. This can sometimes involve a lot of dancing round the mat and turning the ruler over and round, but eventually you will find the right edges to line up (and it is much easier in the privacy of your own home than in a classroom full of students – or ‘sewing in public’ as one of our students described the feeling).

cut triangleCut along the ruler to cut the first triangle.

60 deg triangleTo cut the next triangle you need to dance around the mat again to line the 60 degree line up with one edge of the strip and the ruler going the other way to meet the tip of the triangle you just cut –

cut second triangleContinue dancing and cutting until you have the right number of triangles. You can keep the strip folded and cut two at a time for speed – the shapes are symmetrical.

Diamonds involve slightly less dancing! Thiis time add 1/2 inch to the width of the strip for a seam allowance – for a 2 inch wide diamond, cut a 2 + 1/2 inch wide strip. Trim the end of the strip as before.

trim end to 60 degsNow place the ruler with the 60 degree line along one long edge and the 2 + 1/2 inch line (or the same measurement as your width of strip) along the edge you just cut. You can cut this way –

measure diamondor this way –

measure diamond bYou end up with the same size and shape diamond.

diamond cutJust keep sliding the ruler along the strip to cut more diamonds. Once again you can keep the strip folded and cut two at a time. These diamonds are used in blocks such as ‘Tumbling Blocks’.

 

 

 

 

 

 

 

 

 

Rotary cutting Part 5

Once you can cut strips and then squares, cutting right-angled triangles is easy. Let’s look at ‘half-square’ triangles first. As you might expect by the name they are cut from a square by cutting it in half across the diagonal. The magic number to remember is 7/8 (seven eighths) as this is the seam allowance you need to add to the finished size of the unit. Standard seam allowance in patchwork is 1/4 inch so when cutting squares and rectangles we add 1/2 inch to the finished size of our squares and rectangles when cutting. With triangles we need to add a little more to take account of those pointy ends (technical term). So if your half-square triangle unit finishes at 3 inches once it is sewn into the quilt block then you need to cut the squares 3 + 7/8 inches. If you need to cut lots of these triangles (and you probably will) then first cut a strip that width. Then cut it into squares. Having cut the squares, keep them in their pairs (or fours) as they came from the strip – try not to move them too much. Place the ruler across the first pair from one corner to the other. If you wish you can use the 45 degree line on the ruler – put it against one side of the square – to be certain you are cutting an exact diagonal; but it is possible to get too obsessive about this degree of accuracy.

cut hstAs before, place the cutter on the mat against the edge of the ruler (make sure there is ruler above and below the line you wish to cut), remove the guard, roll the cutter against the edge of the ruler to the end of the square (and a little beyond) and replace the guard. Lift the cutter from the mat and gently check the cut has gone through all layers. If it hasn’t, don’t be tempted to go back and forth with the cutter until it is all cut through as you will only chew the fabric; likewise don’t tug at it to break that irritating thread that hasn’t cut as you will stretch this bias edge. Instead get a small pair of scissors and just snip the triangles apart where they are caught.

Now move onto the next set of squares and repeat until all squares are cut into two triangles.

cut second hst

cut hst done

Quarter-square triangles (or QSTs) are, as you might expect, a square cut in four across both diagonals. This time our magic number for the seam allowance is 1 + 1/4 (one and a quarter) inches. So if our finished quarter-square triangle unit is 3 inches we need to start with squares of 4 +1/4.

As for the HST units above, start by cutting a strip and then cut this into the right number of squares for your units. Once the squares are cut you can cut them into four. Don’t move them! Cut the first diagonal in the same way as for HST units above. Then, without moving the squares (move yourself), place the ruler on the opposite diagonal and cut again. Repeat with all the squares you require.

cut qst first cut

cut qst second cut

cut qst doneYou will find some tutorials for quick-piecing these triangle units and links to easy blocks on the tutorials page of our sister blog Meadowside Designs.

Next time we will look at using the 60 and 30 degree lines on the ruler to cut diamonds and equilateral (60 degree) triangles.

 

 

Rotary cutting Part 4

Having cut some strips the next step is to cut those strips into shapes, starting with squares and rectangles.

From that two and a half strip we cut last time we can cut two and a half inch squares or rectangles of various lengths – the most usual with that width being four and a half inches.

First trim the selvage from the strip. Depending on how many squares or rectangles you want to cut it may be more economical (and certainly quicker) to leave the fabric strip folded in two, or even four.

With the bulk of the fabric to the hand you hold the ruler with, line a line of the ruler up with the cut edge of the strip. Trim off the selvage and ragged edge of the fat quarter or both selvages of the width of fabric (WoF) strip. If you left the WoF strip folded in four then you will cut through the centre fold as well. What you do with these trimmings is up to you – throw them away or save them for ‘leaders and enders’.

trim selvage atrim selvage bNow turn the mat around (or very carefully turn the strip) so the bulk of the fabric is to the hand you cut with. Use the ruler to measure a two and a half inch square and cut – remember to remove the guard only when cutting and replace it as soon as the cut is made. (You will often hear our students muttering “guard off; cut; guard on; guard off; cut; guard on . . .” as they work). Gently move the cut squares a little, measure again and cut the next set of squares. Keep going until you have all the squares you need, remember you will be cutting at least two squares each time.

cut square(you can see in the photo above the slight discrepancy in rulers – the strip was cut with one ruler and a different one is being used to cut the square).

squares cutRectangles are cut in the same way – just measure a longer length. If you need to cut a really long rectangle – longer than the width of the ruler – don’t forget you can turn the ruler round and measure along its length. For really big pieces you can use the mat for measuring.

cut rectangleYou can find a tutorial for using your strips and squares to make 4-patch and 9-patch units and also some instructions for blocks using these units on our sister blog Meadowside Designs.

Rotary cutting Part 3

Most rotary cut shapes are cut from a strip so being able to cut straight accurate strips is a vital skill. Last week we got as far as finding and cutting a straight edge on our fabric and this week we will cut a strip (or two) from it.

Before you cut check that the edge is straight – something happens to fabric left out overnight and all those beautiful straight edges turn wavy and frayed, we blame the fabric imps.

Now turn the mat with the fabric on it so that the bulk of the fabric is now to the hand you cut with. You can turn the fabric but be very careful that you keep those straight edges together if you have yardage and, somehow, even with fat quarters, the mere act of picking it up seems to stretch it all out of shape.

Fold the fabric up again making sure those straight edges are aligned exactly (or as near as you can possible make it).

fold fabricDecide, work out, or look up the size of strip you need to cut. If it is two and a half inches (a very common measurement) then find that on your ruler. Place the ruler on the fabric so that the required measurement is against the straight cut edges. The fold of the fabric should be towards you.

cut stripHold the ruler firmly, fingers out of the way!

photo6 hand positionPlace the cutter on the mat and remove the guard. With the blade snug against the ruler roll the cutter with a firm and even pressure along the ruler to cut the strip. You will be going through two or four layers but with a sharp blade this shouldn’t be a problem.

strips cutRemember you will cut more evenly, more surely and more accurately if you are standing in front of the ruler edge where you are cutting. Never be tempted to cut across yourself and never, never cut towards you – not only is it not very accurate (the ruler and fabric move and you can’t gain enough pressure) but the consequences of the blade slipping and cutting into you are potentially catastrophic.

You can download a handy list of Chris and Barbara’s Dos and Don’ts for rotary cutting here.

The instructions above are for using the ruler to measure and cut strips. This is the way Chris does it. Barbara uses the mat for measuring and the ruler as a straight edge guide for the cutter. Both methods are equally valid – whichever method you use however, be consistent as rulers and mats are slightly out of sync with each other (even different makes of ruler never quite line up exactly). There may be only microns of difference but over several seams those add up and decrease the accuracy of your piecing.

Next time – cutting some shapes from the strips.

Rotary cutting Part 2

Most instructions tell you to cut strips on the straight grain, or to cut bias strips – but how do you find these? Its relatively easy if your fabric still has its selvage – the straight grain is at right angles (lengthwise grain) or parallel to the selvage (cross grain). The cross grain has slightly more ‘give’ than the lengthwise grain. The bias is at 45 degrees to the straight grain and is very stretchy.

We usually cut our strips at right angles to the selvage (on the lengthwise grain). Try to leave the selvage on your fabric for as long as possible – only cut it off once you are cutting shapes from the strips you have cut – as this will make it easier to straighten the fabric next time you need a cut a strip or two from it.

If you have yardage then fold it in half so the selvages come together. Hold it up and away from you then shuffle the selvage edges along until the fabric hangs straight and the fold at the bottom has no ruckles. Hold on tight to those selvages and place the fabic onto the cutting mat with the fold towards you and the bulk of the fabric to the hand you don’t cut with (the left if you are right-handed; the right if left-handed). You may need to turn the mat so that the whole length is on the mat – it makes this first cut much easier.

trim yardageIf you have a fat quarter – this is half a width of fabric and should have one selvage – don’t fold it, just place it on the cutting mat so the selvage is away from you and the bulk of the fabric is to the hand you will hold the ruler with.

find straight grainFrom now on yardage and fat quarters are cut in the same way. So . . . Deep breath. Stand up over the mat (try to have it at a comfortable height – a kitchen worktop is ideal if you are doing a lot of cutting) so you are in direct line with the edge you wish to cut. Place the ruler on the fabric so that one line of the ruler lines up with the selvage (this may be a bit hit and miss and some selvages can be a somewhat wavy – take an average) – if you managed to get the yardage hanging straight then the fold should also be on a straight line of the ruler, but don’t obsess about it.

trim yardage bFat quarters have been cut from a machine wound bolt (and some are pre-cuts) so the bottom edge is rarely parallel with the selvage. Move the ruler until you are cutting just enough fabric off the edge to straighten it. Start with the cutter on the mat, hold it at about 45 degrees (or whatever you find most comfortable), remove the guard, make sure the blade is snug against the ruler, that your fingers are out of the way . . .  another deep breath . . . And . . .  with a firm and even pressure roll the cutter along the edge of the ruler to trim that excess fabric away. You may have to ‘walk’ your hand up the ruler to keep it by the cutter and to keep the ruler firm and straight. Once you have finished the cut and reached the end of the fabric put the guard back over the blade and lift the cutter from the mat. And breathe.

trim straight grainNext time we will be cutting strips from our nice straight fabric. Find some old sheets or fabric you don’t like and can’t think why you bought it (except it was possibly a bargain) for practice.

Rotary cutting. Part 1

This is one of the most popular technique classes we teach so we thought we’d bring you a few hints, tips, photos and general ‘thoughts’. First things first – you will need a rotary cutter, a ruler and a mat.

DSCF2783The mat is vital to protect your furniture (or carpet) and your cutter. Don’t be tempted to buy a small mat – its almost impossible to cut a full width-of-fabric strip on a small mat; buy one that is at least 24 inches x 18 inches. This size is still small enough to take to class but large enough to be useful.

The most useful ruler size you can buy is probably 6 x 24 inches (although Barbara prefers a slightly smaller one). 6 x 12 is also useful, as is a 12 inch square. With these three you can cut pretty much anything and everything you are going to need to. There are plenty of other rulers for all sorts of ‘time-saving,’ or super-accuracy, or ‘trimming to fit’; rulers for triangles, for diamonds, for wavy lines; buy these only once you can see a need for them.

Cutters too come in all sorts of shapes and sizes. We suggest you buy one with a 45mm blade, no smaller except for cutting curves. The larger size (60mm) is great if you do a lot of cutting through multiple layers. Try out the various sorts of cutter to see which one suits you – especially if you have wrist problems. Quilt shows are the ideal place to do this as there will be plenty to choose from. You can sometimes find very cheap cutters in discount shops – two of the cutters in the photo were only £1 – these work very well if you put a good quality blade in them but the blade will probably cost five times what the cutter did!

Look after these tools – keep the mat flat and away from heat (including the sun) or it will warp. Change the blade on your cutter regularly; once you find yourself having to press hard to cut through two layers then the blade needs changing. You can send blades away to be sharpened or you can buy a sharpener to do it yourself at home (there are several sorts). Our experience is that the blades are never quite as sharp as they were from the factory – but they will do for a while, just don’t expect to cut through eight layers of fabric. You can find a photo step-by-step tutorial on changing the blade on a cutter here. Remember these cutter blades are very sharp – even when too blunt to cut fabric – so treat them with respect, handle with care, and always keep the guard over the cutter blade except when you are actually making the cut.

Next week we’ll look at finding the straight grain of the fabric and cutting strips.