Look at this quilt for a while and it keeps reorganizing itself. First you see rows of little squares standing on their corners. Then the eye joins four of them up and you see large diamonds instead. Then the pale background takes over and the diamonds become the holes between pinwheels. Nothing on the surface moves, but the design will not settle, and that is the whole trick of it.
Foundry is a free quilt pattern from Robert Kaufman, 60 inches by 72 inches, and the engine underneath all that movement is one humble unit repeated 150 times. It is the square-in-a-square: a small square turned on point inside a larger one, with four triangles filling the corners. Thirty blocks, two styles, 1110 pieces, and no sashing or borders anywhere to break the grid. The cover rates it Experienced Intermediate, under the line "I know the ropes and would like to test my skills!"
The pattern was designed by Robert Kaufman Fabrics and photographed in Studio Stash, a collection by Jennifer Sampou. It is shown in a colorstory called Warm, with Neutral and Cool versions at the back of the file. The rest of their free patterns live at robertkaufman.com.
Pattern details
- Pattern name: Foundry
- Brand: Robert Kaufman
- Designer: Robert Kaufman Fabrics
- Finished size: 60" x 72"
- Size category: Throw
- Difficulty: Experienced Intermediate
- Block: Square-in-a-square, two block styles, 12 1/2" unfinished
- Technique: Square-in-a-square, half square triangles
- Colorway shown: Warm, with Neutral and Cool alternates
- Fat quarter friendly: No
- Jelly roll friendly: No
- Layer cake friendly: No
- Charm pack friendly: No
Download the free Foundry quilt pattern PDF
Why the center square is cut at 3 3/8 inches
Of all the measurements in this pattern, the one that looks made up is the center square. Everything else is familiar: 2 1/2 inch squares, 2 7/8 and 4 7/8 inch squares cut once on the diagonal. Then the center of every square-in-a-square unit is a 3 3/8 inch square, which is a size most people never cut.
It is not arbitrary. A square turned on point is measured across its diagonal, and the diagonal of a square is its side multiplied by 1.414. Work it backward from the finished unit and the number falls out. Each unit finishes at 4 inches. The square inside it sits corner to corner across that 4 inches, so its finished side has to be 4 divided by 1.414, which is 2.83 inches. Add a quarter inch of seam allowance on each side and you cut at 3.33 inches. Three and three eighths is 3.375. That is the nearest eighth above, with a sliver to spare for trimming.
This is worth knowing because it means you are not stuck with 4 inch units. Decide what you want the unit to finish at, divide by 1.414, add half an inch, round up to the nearest eighth, and you have the center square for any size. The corner triangles then come from squares cut 7/8 of an inch larger than the finished unit, cut once on the diagonal, which is where the 2 7/8 inch squares in this pattern come from for 2 inch finished triangles.
Both figures are generous on purpose. Every square-in-a-square step in this pattern ends with the same four words: trim to 4 1/2 if necessary. The units are built slightly oversized so the trim can square them up, which is the only way 270 separate units arrive at the same size.
Two blocks, nine units each
Thirty blocks, fifteen of each style, every one a three by three grid of 4 1/2 inch units. Lay them out and the structure is easy to hold:
The A Block puts four half square triangles in the corners, four square-in-a-square units along the edges, and one more square-in-a-square in the middle. The middle one is different from the other four: its four corner triangles are all the same fabric, where the edge units use two fabrics on opposite pairs of corners. That one change is what makes the center read as a separate shape rather than as more of the same.
The B Block swaps the corners. Instead of a half square triangle, each corner is a small square with two triangles on adjacent sides, forming a triangle unit, and then a large triangle on top. Four of those, four square-in-a-square edge units, one square-in-a-square center. Same nine-patch skeleton, different corner.
Set them alternating, six rows of five, and the corners of neighboring blocks meet to form the shapes that keep reorganizing. Three rows start and end with an A Block and three start and end with a B Block, so the alternation runs in both directions.
Pressing is specified more carefully than usual, and it is worth following rather than improvising. Seam allowances are pressed open inside the units. Then within each block, the top and bottom rows press one way and the middle row the other, so the three rows nest. Then block seams go to the right in even numbered rows and to the left in odd numbered rows, with the row seams open. With thirty blocks meeting edge to edge and no sashing to hide behind, that alternation is what keeps the junctions flat.
The piece count, checked against the cutting list
We added up every shape the cutting instructions produce and every shape the assembly steps consume. The quilt comes to 1110 pieces: 33 in each A Block and 41 in each B Block.
- 150 square-in-a-square units, which is 60 edge units and 15 centers in the A Blocks and the same again in the B Blocks
- 60 half square triangles, all in the A Block corners
- 60 corner units in the B Blocks, each one a square plus three triangles
- 270 units in total, every one of them trimmed to 4 1/2 inches
The binding closes too, which is a nice check that the pattern was written by someone counting. Seven strips at 2 1/4 inches, joined end to end, give you roughly 277 inches of binding once the diagonal joins are taken out. The quilt perimeter is 264 inches, and the rest covers the corners and the overlap where the ends meet. Note the width: 2 1/4 inches, not the 2 1/2 that many patterns default to, which gives a slightly narrower finished binding.
One letter in the pattern is wrong, and here is the proof
There is a real error in the Warm and Cool instructions, and it will stop you dead at the cutting table if you do not know about it. In the A Block, Step 3 says to sew four Fabric L triangles to each side of a Fabric J square. It should say Fabric K.
Three things show it:
First, count what Fabric J is asked to supply. Step 2 of the A Block needs 60 Fabric J squares and Step 3 asks for 15 more, which is 75. The cutting list cuts 60.
Second, look at Fabric K. The cutting list produces fifteen 3 3/8 inch squares from it, and Fabric K then appears nowhere else in the entire pattern. Fifteen is exactly the number of A Block centers.
Third, the B Block does the same job with two different fabrics, 60 centers from one and 15 from another, and so does the Neutral colorstory at the back of the file, which is a clean reletter of the same design. The structure is consistent everywhere except that one line.
Use Fabric K for the fifteen A Block centers and every fabric in the quilt is consumed exactly, with nothing left over and nothing short. Use Fabric J and you finish fifteen squares short with fifteen Fabric K squares sitting unused on the table.
One smaller note while you are in the back half of the file. The Neutral colorstory on pages 10 and 11 is described by the pattern itself as an abbreviated version, and it tells you to refer back to pages 4 to 6 for the illustrations and pressing. Take that instruction seriously and read the two side by side before cutting, rather than working from the short version alone.
Trimming is the job
Four separate steps in this pattern end with trim to 4 1/2 inches, and between them they cover 270 units. That is not a finishing touch, it is the main activity. A quilt with no borders has nothing to absorb a drift, so 270 units that are each a sixteenth of an inch generous add up to a top that will not lie flat.
A square ruler in a size close to the unit is the tool that makes this bearable, because it lets you line up the center of the unit and trim all four sides from one placement instead of flipping a long ruler four times. Our quilting rulers cover that size range. And with 1110 pieces to cut before any of the trimming starts, it is worth having a fresh rotary blade on hand, because the blade that was clean through the first fabric is skipping threads by the ninth. How to cut fabric accurately covers the ruler and blade checks that fix most cutting drift.
The 60 half square triangles in the A Block corners are the one place you can save real time. The pattern builds them the straightforward way, one pair of triangles at a time, but there are faster methods that give you two, four or eight at once from larger squares. Our half square triangle methods and size chart sets them out with the cut sizes for each.
Fabric and palette
Twelve fabrics in the Warm version, and the way they are distributed is the reason the quilt keeps shifting. The square-in-a-square units do not use one background and one feature. The edge units take two different fabrics on opposite pairs of corners, so each unit already reads as two half units, and when four of them meet across a block seam those halves line up into something new.
Which means value matters more than color here. Before you substitute anything, lay your twelve choices out and photograph them in black and white. You need a clear light group, a clear dark group, and a mid group that can go either way depending on what it sits next to. If everything lands in the middle, the shapes will not separate and the quilt will read as texture instead of pattern.
Scale is the other constraint. The center squares finish at under three inches and the corner triangles at two, so a large print cut into those loses its design entirely. The sample keeps its busiest fabrics in the larger corner triangles of the B Block, where there is room for them to be seen, and uses flat or nearly flat fabrics everywhere small.
One detail in the cutting list is easy to miss and saves you a whole fabric. A note tells you to cut all the Fabric L pieces from the leftovers of Fabric C, so although L is listed in the fabric chart, you do not need to buy it separately if C gives you enough.
Before you start
The backing takes 4 yards. At 60 inches wide, that means two lengths joined down the middle unless you use a wide backing fabric, which covers a quilt this size in one piece. Our guide to cutting and joining a quilt backing covers both routes and which seam holds up best.
For the binding, remember the 2 1/4 inch width rather than the usual 2 1/2, and if you want a refresher on joining and attaching it, our step by step guide to quilt binding walks through it.
And if 60 by 72 is not the size you need, settle that before the first cut rather than halfway through. Adding a row of blocks changes every number in the cutting list, and our quilt size chart is the place to work it out.
If this one is more quilt than you want to take on right now, there is plenty more in our collection of free quilt patterns. Foundry will keep.
