Three Hundred Thirty-Six Ends Before the Edge Pulled Inward

Diane’s loom was already warped when she lent it to me—about halfway through a project she’d abandoned two months ago. I cut the warp threads off, pulled the heddle out, and stared at 168 empty slots and holes alternating across a 16-inch width. Threading this thing would take two hours minimum, and I’d get it wrong at least once.

Warping a rigid heddle loom is the part nobody warns you about. The tutorials gloss over it in thirty seconds: “Thread each end through a slot or hole, following your pattern.” What they don’t mention is that you’re threading 300-400 individual warp threads, one at a time, maintaining consistent tension across all of them, and if you make a mistake twenty threads in you might not notice until you’re at thread 180 and the shed won’t open properly because you put two threads through the same hole fifteen minutes ago.

What a Rigid Heddle Actually Does

Floor looms separate the reed (the comb that beats the weft tight) from the heddles (the frames that lift warp threads). A rigid heddle combines both functions into a single unit. The slots let threads pass through freely. The holes hold threads that lift when you raise the heddle or drop when you push it down. This creates two shed positions:

Heddle up: Threads in holes rise above threads in slots
Heddle down: Threads in holes drop below threads in slots
Heddle neutral: Everything’s level, and you can beat the weft

Plain weave alternates these positions—shuttle through, beat, lift heddle, shuttle back, beat, drop heddle. The rigid heddle makes this dead simple, which is why it’s portable and learner-friendly. It also limits you to plain weave and pickup stick patterns unless you add a second heddle, but that’s topology for another day.

Threading Order Determines Everything

For plain weave, you thread alternating: slot, hole, slot, hole, across the width. This gives you an equal split—half the warp lifts, half stays down. The threads in slots form one shed position, threads in holes form the other.

Here’s what I got wrong the first time: I threaded straight across without considering edge reinforcement. Traditional handweaving puts extra threads at the selvages—the edges where the weft loops back. These edges take more stress than the centre, so you might thread hole-hole-slot-hole-slot… for the first few, then switch to standard slot-hole alternation for the middle, then hole-hole again at the far edge. Diane’s abandoned warp had done this. Mine hadn’t.

Second attempt: followed the 2-2-2 selvage pattern I’d found in a 1974 weaving manual. Two holes, two slots, two holes at each edge, regular alternation in between. Took 90 minutes to thread 336 ends (168 per side of centre), working front-to-back. Each thread gets pulled from the warp bundle, through the reed/heddle, tied temporarily to a bar at the front. Then you wind tension onto the back beam, secure the front, and hope everything’s even.

It wasn’t.

Tension Problems Reveal Themselves Slowly

Same problem as the macramé cord—materials that lie while you’re working. The warp looked fine when I finished threading. Lifted the heddle to check the shed. Clean opening, no crossed threads, symmetrical depth. Started weaving.

Three inches in, the right edge was pulling inward. The fabric was narrowing.

This is called draw-in, and it’s the signature failure mode of beginner weavers. You can calculate it. If your warp is 40cm wide and you’re getting 38cm of woven fabric, you’ve got 5% draw-in. Some draw-in is inevitable—weft has to curve over and under warp threads, creating inherent pull—but anything over 3-4% means your edge tension is wrong.

The geometry is straightforward. Weft doesn’t travel in a straight line—it follows a sine wave through the fabric, cresting over each raised warp thread, dipping under each lowered one. The amplitude of that wave determines how much horizontal distance the weft actually covers. If your weft is too tight, it pulls the outermost warp threads inward as it tries to straighten itself. The selvage threads bear the entire corrective force.

Measured my selvage threads with a fish scale (borrowed from fly-tying supplies, marked in grams). Centre warp threads: 180g of tension. Selvage threads: 340g. No wonder they were pulling.

The fix isn’t to loosen the selvage threads—that creates a different problem (loose edges that won’t hold their shape). The fix is weft angle. When you throw the shuttle across the shed, the weft needs slack. It should form a shallow curve before you beat it in, not a straight line. That curve becomes the sine wave amplitude. Pull it straight and you force the fabric to narrow to accommodate the missing length.

Beating Tension Compounds the Error

After each pick, you beat the weft tight using the heddle in neutral position. This compresses the weave, determines fabric density, and locks in whatever mistakes your weft angle made. Beat too hard with tight weft and you’re compacting stress into the selvage. Beat too soft and the fabric gaps.

Consistency matters more than force. I measured beat pressure for twenty picks: ranged from 2.1N to 4.8N (measured by pressing the heddle against a kitchen scale while beating). That variation shows up as visible bands in the fabric—tight sections alternate with loose ones every few centimetres.

Hand-weavers develop kinaesthetic memory for this. They beat by feel, the same way sashiko stitching maintains that 3:2 ratio without measuring every stitch. It’s repetitive motion calibrated through hundreds of picks, feedback encoded in how the reed sounds when it strikes the fell of the cloth. A sharp ‘tack’ means you’re hitting compressed fabric. A dull thud means there’s still air in the weave.

I’m not there yet. My beats are inconsistent, my weft angle drifts, and my selvages pull. The right edge is now 1.2cm narrower than the left edge over a 12cm length of weaving. That’s 10% differential draw-in. Unacceptable for anything you’d want to use, but useful as a demonstration of how quickly these errors accumulate.

Tomorrow I’ll cut this off and start a new warp with the correct selvage reinforcement and a longer weft allowance. The loom stays set up on Diane’s folding table, the shuttle sits next to it loaded with too-tight weft, and there are 324 more warp threads waiting to teach me what consistent tension actually feels like.