Blade-21.6 in
Likely- 137-1999-03 — Toro 77404 TimeCutter 42in Zero Turn Mower, SN 400000000-417999999
42in deck takes 2 identical 21.6in blades (one per spindle) - the parts-list legend shows the blade, the spindle assembly and the mounting bolt only ONCE each because both spindle positions share the same part number, which is normal for a PartsTree flat legend and is not evidence of a single-blade deck. Toro's own official spec page for model 77404 independently states "Number of Blades: 2", confirming 2x qty needed. No separate blade adapter exists on this deck - the blade bolts directly to the spindle shaft.
Source: Toro 77404 - Toro 42" Timecutter Zero-Turn Mower (SN: 400000000 - 417999999) - 42in Deck and Decal Assembly Parts Lookup and Diagrams | PartsTree — 42in Deck and Decal Assembly exploded diagram, item/reference #11: "Toro 137-1999-03 ... BLADE-21.6 IN". Read via the browser tool's raw DOM text (get_page_text), not an LLM-summarized fetch, after an earlier summarized pass mis-stated the blade count as 3.
Changed partway through production: PartsTree diagram and Toro's official model-specific spec page both confirmed for serial range 400000000-417999999 only. Toro lists 5 further, newer serial-range configurations for model 77404 (up to the current 420620000-999999999 range) that were not checked this pass - re-verify against the unit's actual serial number if it falls outside 400000000-417999999.
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