Yarn weight refers to the thickness of a yarn. Thickness determines appropriate needle or hook size, finished fabric density, and yardage requirements. Standard weight categories from thinnest to thickest: lace, fingering, sport, DK, worsted, bulky, super bulky.

Weight labels on yarn are approximate. Wraps per inch (WPI) gives a more precise measurement. To measure WPI: wrap yarn snugly around a ruler for one inch, without overlapping strands or stretching. Count the wraps.

WPI reference:

• 30+ WPI: lace
• 20–28 WPI: fingering
• 14–18 WPI: sport
• 11–14 WPI: DK
• 9–11 WPI: worsted
• 7–8 WPI: bulky
• Fewer than 7 WPI: super bulky
  

WPI is most useful when a label is missing, when substituting yarns, or when working with handspun yarn.

Gauge is the number of stitches and rows per inch in a knitted or crocheted fabric. It is determined by yarn weight, needle or hook size, and individual tension. A pattern’s gauge is the measurement the designer used to calculate sizing. If your gauge does not match the pattern, your finished dimensions will differ. A small difference over many inches makes a big difference in fit.

To adjust gauge: a smaller needle or hook produces more stitches per inch; a larger needle or hook produces fewer. The goal is to match the pattern’s gauge, not its suggested needle size.

Sett is the weaving equivalent of wraps per inch (WPI). Sett controls how open or dense the finished woven cloth will be. A standard starting point for sett is half the WPI for a balanced plain weave. Twill structures generally require a slightly closer sett; lace structures a more open one.

Both gauge and sett are starting points that need to be confirmed by sampling. Calculate first, then verify with a swatch. Record what you find; your future self will thank you.

Blocking is the process of wetting a finished piece, shaping it, and allowing it to dry. It evens out stitches, sets the final dimensions, and for lace, opens the pattern fully.

For protein fibers (wool, alpaca, cashmere): soak in cool water with a small amount of wool wash until fully saturated, typically 15 to 20 minutes. Gently press out water without wringing. Roll in a towel to remove excess moisture. Lay flat, shape to finished measurements, and pin if needed. Allow to dry completely before moving.

For lace pieces, blocking wires threaded through edge stitches produces cleaner lines than pins alone.

Fiber-specific notes:

• Wool holds its blocked shape well once dry.
• Silk and silk blends block well and dry quickly.
• Linen and cotton do not respond to blocking the same way protein fibers do, but wet finishing still softens and settles the fiber.
  Steam blocking is appropriate for fibers that should not be fully saturated. Hold the iron several inches above the surface. Do not press down on wool -- direct pressure and heat flatten the fiber's loft.
  
  Block to finished measurements, not to the dimensions of the piece as it came off the needles or loom.