Setting triangles

[RJR_38]

I am doing a (what I thought was simple!) pattern to use up scraps. It is heart shapes set on-point - 11 inch finished block. I have started to sash in-between heart shape in one direction and am now coming to the setting and corner triangles.

I know how to calculate them with the formula but I cant work out if I should leave the ends 'unsashed' and use 11 as finished block or if I should put my 1.5 finished sashing on and use 12.5 as finished block size? Or something else? The more I think about it the more confused I get... @Iminei or anyone else who can help?

[BrendaP]

Sketchbook and coloured pencils is what you need.

I inherited several wire bound books from my Dad which have 1/4 inch squared paper - the sort used in primary schools for arithmetic - which I find useful for sketching out quilt designs.

[Efemera]

I’ve just been through all this and thought it would be just a matter of quartering or halving the blocks... but I needed to add the 1/4 in allowance to make it look right when the binding or border was attached.

[Iminei]

@BrendaP  the Goddess of Colour and Magician of Maths is whom you need really ...

If I had to sort this I would measure the long edge of the sashing/block and add 1/2" - 1"
Cut a square from gash fabric that size,
cut into two triangles on the diagonal and try that ...

for as many goes until you get the right size

Then making sure you have all the correct measurements written down
Do it again in the real fabric.

Expert ... Moi ??? !!! 

[Flobear]

I have half a bin full of triangular pieces and an A4 sheet of scribblings from my efforts to get the right size triangles for my mug-rug so I know Imi's suggested method works.

Eventually 

[Deafoldbat]

Measure the diagonal corner, get a calculator and multiply that measurement by itself, then divide the result by 2, then find the square root of that number. This will give you the side length of the square you need. Add ⅞inch to that - or an inch if you aren't sure of your cutting accuracy. You can always trim it if needed Cut 2 squares of the appropriate size and cut them in two on the diagonal. This gives you the straight grain on the outside edges so it won't stretch.

For the side setting triangles, measure the side of the block (ie a short side of the required triangle). Multiply that by itself, then double the result. Find the square root of that number, and add i¼ inches to it. Cut a square that size and cut the square across both diagonals to give you 4 x quarter square triangles. The straight grain will be on the long edge which will be on the outside and won't stretch.

If this all sounds vaguely familiar it's because you weren't looking out of the window all the time in the geometry lessons. Remember Pythagoras's Theorem? This is the only use I've ever found for it. 

[BrendaP]

Remember Pythagoras's Theorem? This is the only use I've ever found for it. 

I think it's the only use I've ever found for it too!

[RJR_38]

Thanks everyone - I knew the formula etc but wasn’t sure if it was the block or block+sashing you used as the base number but all sorted and quilt top mostly finished now - just 2 border strips to add next weekend

[Iminei]

Pythagawho ?????

To add to my foolproof method, if youre short on fabric you can also cut out the squares from paper or paper napkins until you find the right size.

[BrendaP]

When it comes to cutting those large setting triangles I favour cutting on the big side - you can always trim off any excess but you can't stick it back on.  And make sure the long side in on grain,  cut quarter square triangles, not half square triangles.

[RJR_38]

Thanks BrendaP. Yes 1/4 square for setting and 1/2 for corners according to my guide. This worked perfectly for everything except bottom 2 corners.... so ended up making my own thing. It must be the layout I chose... but done now lol

[Iminei]

Pics ?????

[RJR_38]

I need to add a top and bottom strip at the weekend and will then post. I don't get time to sew in the week