Treadle Expander
Found on the Tools Menu
Available on Desktop and Mobile.
What It Does
Treadle Expander is the opposite of Treadle Reducer. It eliminates double-press treadle combinations by giving each unique shaft pattern its own dedicated treadle. After expanding, every pick in your treadling uses exactly one treadle — no more pressing two at once.
This is useful when you've been working with a reduced treadle set (using double-presses) and now want to move to a loom with more treadles, or when you simply prefer the simplicity of one treadle per pick.
Opening Treadle Expander
Ribbon: Tools tab > Treadle Expander button
Tap Tools on the rail (tablet) or the bottom dock (phone), then Expand Treadles… under Optimize
The Treadle Expander Dialog
Analysis (Left Panel)
When the dialog opens, it automatically analyzes your draft and shows:
Current Treadles How many treadles your draft currently uses.
Multi-Treadle Picks How many picks in your treadling currently require pressing more than one treadle simultaneously. If this is zero, there's nothing to expand — every pick already uses a single treadle.
Unique Lift Patterns The total number of distinct shaft combinations across all your picks. This is how many treadles you'll need after expanding — one for each unique pattern.
Max Treadles The maximum number of treadles allowed (up to 128). If your unique lift patterns exceed this, you won't be able to expand. In practice, this is rarely a concern.
Preview (Right Panel)
Shows your original tie-up and the expanded tie-up side by side. The expanded tie-up will have one column per unique shaft combination. This updates after you click Expand.
Isolate Shafts
Below the analysis is a second tool for a different problem: a draft whose treadles are heavy rather than doubled. A folded double cloth is the classic case: every bottom-layer treadle also lifts the whole top layer, so each press raises six or eight shafts.
Isolate Shafts moves a chosen set of shafts onto a new treadle at the far left and lightens every treadle that includes all of them to its remainder. The picks that used those treadles become two-treadle presses: left foot on the isolation treadle, right foot on the lightened one. The cloth is unchanged, because the two treadles together lift exactly what the one heavy treadle did.
The shaft box pre-fills with the best candidate found in your tie-up: the largest set of shafts shared by the most treadles. Type your own as
1,2,3,4or1-4.Create Treadle previews the new tie-up and reports how many treadles were lightened, how many picks now press two treadles, and the heaviest press before and after.
Apply turns multi-treadle mode on for the draft. Undo reverses the whole operation.
If a treadle already ties exactly that set, it is reused in place instead of adding a new one.
Isolate Shafts works even when there is nothing to expand; heavy single-treadle drafts are exactly its use case. Like expansion, it needs tie-up mode: a liftplan draft is converted to a tie-up first (Design → Mode).
How to Use It
Go to Tools tab > Treadle Expander
Review the analysis — check how many multi-treadle picks exist and how many unique lift patterns there are
Click Expand Treadles
Review the result and the preview
Click Apply if you're happy with it
Understanding the Results
After clicking Expand, you'll see one of these outcomes:
Expanded (more treadles) — The most common result. Your treadle count increases to accommodate all the unique shaft patterns, and every pick now uses a single treadle. For example, "8 → 12 treadles."
Expanded (same count) — Your treadle count stayed the same, but multi-treadle picks were eliminated. This happens when the double-press combinations happened to match existing treadle patterns.
Optimized (fewer treadles) — Occasionally, expanding actually reduces your treadle count. This can happen when your original draft had redundant treadles — different treadles that raised the same shaft combinations.
Exceeds maximum — The pattern requires more treadles than the maximum allows. This is rare, but it means the draft has too many unique shaft combinations to fit in single-treadle mode.
Step-by-Step Example: Preparing for a Larger Loom
You've been weaving a pattern on an 8-treadle loom using double-presses. Now you're moving to a 16-treadle loom and want to simplify the treadling:
Open Treadle Expander from the Tools tab
You see "Current Treadles: 8" and "Multi-Treadle Picks: 45" and "Unique Lift Patterns: 12"
Click Expand Treadles
The result shows "Expanded: 8 → 12 treadles (all multi-treadle picks eliminated)"
Your 16-treadle loom can handle 12, so click Apply
Every pick now uses a single treadle. The treadling is easier to follow and you never have to press two at once.
What Changes in Your Draft
When you apply an expansion:
Tie-up — Each unique shaft combination gets its own treadle column. The tie-up may have more columns than before, but each one maps to exactly one lift pattern.
Treadling — Switches from multi-treadle mode to single-treadle mode. Every pick shows exactly one treadle.
The cloth — Unchanged. The same shafts rise on the same picks, producing identical fabric.
Limitations
Tie-up mode only — Treadle Expander is not available in liftplan mode. Convert to tie-up first (Tools tab > To Tie-up).
Requires multi-treadle picks — If your draft already uses single treadles for every pick, there's nothing to expand. The dialog will let you know.
Tips
Undo works — Ctrl+Z (Cmd+Z) reverts the expansion in one step.
Check the count first — The "Unique Lift Patterns" number tells you exactly how many treadles you'll need. Make sure your loom can accommodate that many before expanding.
Pairs with Treadle Reducer — Reducer and Expander are complementary tools. Reduce when you need fewer treadles (accepting double-presses), expand when you have enough treadles and prefer single presses. You can go back and forth freely.
After importing — Some imported WIF files use multi-treadle notation. If you prefer single-treadle picks, Treadle Expander is a quick way to convert them.
Quick Reference
Location
Tools tab > Treadle Expander
Works in
Tie-up mode only (not liftplan)
Input
Draft with multi-treadle picks (double-presses)
Output
One treadle per unique shaft combination, single presses only
Treadle count
May increase, stay the same, or occasionally decrease
Cloth
Unchanged — identical before and after
Isolate Shafts
Moves a set of shafts to a new far-left treadle; heavy presses become two light ones; cloth unchanged
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