Today's Quilter - UK (2020-01)

ESSENTIAL GUIDE lon-point settings

FABRIC GR AIN

Theotherimportantthingto understandwhenusingon-pointsettings

is theneedto considerfabricgrainwhencuttingthesettingandcorner

triangles.A primeaimin patchworkis to keepthepatchesas stableas

possible,andthisis achievedbyusingthefabricgrain.Fabricis less

stableandhasmorestretchalongits45-degree(bias)direction– see

Fig 5. Therefore,whencuttingtriangles,theaimis to avoidhaving

thesestretchybiasedgesontheoutsideedgesof a blockorproject.

Fig 5 showsthemainfabricdirections.It alsoshowssquarescutinto

fourtrianglesandtwotriangles,withtheredlinesshowingthebias

(stretchy)edges.Thisis whyinstructionsforcuttingtrianglessaycut

a squareintofourtrianglesforsettingtrianglesbutcutintotwo

trianglesforcornertriangles.Fig 6 showshowthesetrianglesare

placed in a design. The stable edges are shown as blue lines.

MATHS FOR

SETTING

TRIANGLES

So,weknowhowdiagonalmeasurementsare

calculated,whyfabricgrainis importantandwhy

trianglesarecutdierentways.Wecannowlookat

themathsforworkingoutwhatsize of squares need

to be cut for setting triangles.

1

Finishedblocksizex 1.414(round to nearest

in)=finished diagonal.

2

Add 1 in (1.25in)(forseams)to thisfinished

diagonal measurement=size of square to cut.

3

Cutthesquarediagonallytwiceto givefour

settingtriangles.Repeatto cut the number of

setting triangles needed.

Example

If wehavea finishedblocksizeof 3in(3in

unfinished),thenthesizeof squareto cutforsetting

triangleswouldbe 5in,calculatedas follows:

Fig 5 Fabric grain

Fig 6 Trianglesin placeshowingstable edges

Selvedge Selvedge

Crosswise grain (weft threads)

Straight grain (warp threads)

Bias directions

Setting

triangles

Corner

triangles

1

Finishedblocksize3in x 1.414 = 4.24in (4in) =

finished diagonal.

2

Add 1 in (1.25in) to 4in = 5in = size of

square to cut.

3

Cutthesquarediagonallytwiceintofoursetting

triangles.Repeatas needed.Fig7Ashowsthe

relativesizesof theblockandthetrianglesandFig7B

showstheextra size needed on the triangle, to allow

for seams.

Fig (^7) Corner triangles
5 in
squarecut
intofour
setting
triangles
Trianglewill
belarger
thanblock
toallowfor
seam
allowance
Block
Setting
triangle
B
3 in
unnished
Block block size
Stable edge A