A question for you math geniuses
10-13-2011, 04:44 AM
#12
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Location: Michigan
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Originally Posted by LyndaOH
The formula is to take the seam allowances off the original size of the pieces and then multiply those sizes by the amount you want the percentage of the original piece you want it. So if you have a pattern that is 100 x 100 and you want it 80 x 80, you want it to be 80% of the original size.
The problem is that these sizes don't always convert to nice even numbers. Ideally you'd try to find measurements that are easy to deal with.
The problem is that these sizes don't always convert to nice even numbers. Ideally you'd try to find measurements that are easy to deal with.
It's a three step process:
step 1 subtract 1/2 inch from all dimensions to remove the seam allowance. This accounts for a quarter inch seam on both sides.
Step 2 multiply the dimensions from step 1 with the percent you want to reduce your piece by
Step 3 add the 1/2 inch seam allowance back on
So if you had a rectangle that was supposed to be cut 2.5 X 8.5 and you wanted to make the item 75% of the original size,
Step 1 remove seam allowances, so your 2.5 X 8.5 piece now becomes 2 X 8
Step 2 multiply each dimension by .75 so now you get 1.5 X 6
Step 3 add seam allowance back on, so the final measurement would be 2 X 6.5
Of course, the above example was a nice easy rectangle, and when you applied the percent, a nice round number resulted. This isn't always the case. So do all three steps and then round up to the nearest eighth. Odd shaped pieces, like trapezoids may need to be redrawn with a pencil and paper.
10-13-2011, 07:27 AM
#14
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Originally Posted by NanaCsews2
For those that do not have EQ (I am a little jealous):
This link shows how to draft block sizes.
http://www.quilterscache.com/StartQu...tingseven.html
This link shows how to draft block sizes.
http://www.quilterscache.com/StartQu...tingseven.html
10-13-2011, 07:30 AM
#15
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Originally Posted by LyndaOH
It depends on the block and how those pieces fit together.
One way to figure it out is to take off the seam allowances of 1/4" on each side (so 1/2") and then multiply it times 5/6 but it would really help to see the block. I think with those sizes there are multiple pieces and some may be triangles.
One way to figure it out is to take off the seam allowances of 1/4" on each side (so 1/2") and then multiply it times 5/6 but it would really help to see the block. I think with those sizes there are multiple pieces and some may be triangles.
10-13-2011, 01:48 PM
#16
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Join Date: Aug 2011
Posts: 449
I don't know if this will help you but here goes: the 12 sq. pictured is comprised of 4 blocks per row each finished at 3inches..If you want to reproduce the block at 10in. then each of the 4 blocks per row would be 2.5in finished. So. to get a 2.5in finished block you need to start with a 3in..right? Look at the block, looking at each small block that is used to comprise each row. You will see you need to make (2) 3in sq., (8) 3in. 1/2 sq. triangles, and (6) 3in.1/2sq and 1/4 sq. triangles...does that make any sense to anyone but me?
10-13-2011, 01:53 PM
#17
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Join Date: Oct 2011
Location: Heart of Dixie, Sweet Home Alabama
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Originally Posted by PaperPrincess
Originally Posted by LyndaOH
The formula is to take the seam allowances off the original size of the pieces and then multiply those sizes by the amount you want the percentage of the original piece you want it. So if you have a pattern that is 100 x 100 and you want it 80 x 80, you want it to be 80% of the original size.
The problem is that these sizes don't always convert to nice even numbers. Ideally you'd try to find measurements that are easy to deal with.
The problem is that these sizes don't always convert to nice even numbers. Ideally you'd try to find measurements that are easy to deal with.
It's a three step process:
step 1 subtract 1/2 inch from all dimensions to remove the seam allowance. This accounts for a quarter inch seam on both sides.
Step 2 multiply the dimensions from step 1 with the percent you want to reduce your piece by
Step 3 add the 1/2 inch seam allowance back on
So if you had a rectangle that was supposed to be cut 2.5 X 8.5 and you wanted to make the item 75% of the original size,
Step 1 remove seam allowances, so your 2.5 X 8.5 piece now becomes 2 X 8
Step 2 multiply each dimension by .75 so now you get 1.5 X 6
Step 3 add seam allowance back on, so the final measurement would be 2 X 6.5
Of course, the above example was a nice easy rectangle, and when you applied the percent, a nice round number resulted. This isn't always the case. So do all three steps and then round up to the nearest eighth. Odd shaped pieces, like trapezoids may need to be redrawn with a pencil and paper.
10-13-2011, 04:26 PM
#18
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Originally Posted by Nantie
I don't know if this will help you but here goes: the 12 sq. pictured is comprised of 4 blocks per row each finished at 3inches..If you want to reproduce the block at 10in. then each of the 4 blocks per row would be 2.5in finished. So. to get a 2.5in finished block you need to start with a 3in..right? Look at the block, looking at each small block that is used to comprise each row. You will see you need to make (2) 3in sq., (8) 3in. 1/2 sq. triangles, and (6) 3in.1/2sq and 1/4 sq. triangles...does that make any sense to anyone but me?
Thanks
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