Product Description
Shimano 10KJZ Cast Control Cap (BNT1209) | Tension Adjustment Knob
The Shimano 10KJZ Cast Control Cap (BNT1209) is a fundamental external adjustment component for Shimano’s legendary round-profile baitcasting reels. This cap controls the lateral pressure applied to the spool shaft, allowing the angler to fine-tune the "mechanical brake" or spool tension. Proper adjustment of this cap is the primary way to prevent overruns and backlashes during the initial stage of a cast.
Precision-machined with internal threading and an ergonomic knurled exterior, the BNT1209 allows for micro-adjustments even with wet or gloved hands. It often houses an internal friction shim (spacer) that presses against the spool shaft to provide consistent resistance.
Product Specifications
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Part Name: Cast Control Cap / Spool Tension Knob
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Shimano Part Number: 10KJZ
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Alternate Part Number: BNT1209
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Material: Anodized Aluminum / High-Impact Alloy
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Function: Adjusts spool tension to prevent backlashes.
Compatible Reel Models
The 10KJZ (BNT1209) is a staple part for many of Shimano’s most durable round reels. It is a direct replacement for the following series:
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Shimano Calcutta: CT-200, CT-201, CT-400, CT-400S, CT-700, CT-700S (including early 1990s versions).
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Shimano Bantam: BKM-200, BKM-201, BKM-2000, BKM-201FS.
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Shimano Calcutta Silver: CT-200B, CT-201B, CT-400B, CT-400BSV.
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Shimano Catala: 300 and 400 series models.
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Shimano Cardiff: Select 200 and 300 series models (Verify by schematic).
Technical Tip: If your spool tension feels inconsistent, check the internal Cast Control Spacer (BNT1212) located inside this cap. For a detailed view of the cap and its internal spacers, download the official PDF schematics at www.reelschematic.com.
Maintenance & Lubrication Recommendation
The threads and the internal friction surface of the cast control cap are prone to salt buildup and wear. To ensure smooth, precise adjustment and to protect the spool shaft, we recommend Deuthlon Lubricants:
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For the Internal Spacer/Spool Tip: Apply a tiny drop of Deuthlon Power Cast Oil. This high-speed oil reduces friction on the contact point, allowing the spool to spin faster while still maintaining the desired tension setting.
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For the Threads: Apply a light film of Deuthlon Reel Gear Grease to the internal threads of the cap. This prevents "galling" between the aluminum cap and the frame and provides a waterproof seal against salt spray.
Why Use Genuine Shimano 10KJZ Parts?
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Perfect Thread Match: Prevents cross-threading on the reel's side plate, which can be a costly repair.
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Anodized Finish: Specifically treated to resist the corrosive effects of saltwater and UV exposure.
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Ergonomic Precision: Maintains the factory "feel" and height, ensuring your thumb can easily reach the adjustment while fishing.
