Key, 3x20 mm 

In your instruction manual, this part appears on the parts list as:

Item No	Models
203A	LittleMachineShop.com 3536 HiTorque Bench Lathe - 8.5x16 LittleMachineShop.com 3540 HiTorque Bench Lathe - 8.5x20 Various SC4-US SIEG Bench Lathe Travers Tools OT218410 OTMT Bench Lathe - 8.5x16 LittleMachineShop.com 7500 HiTorque Bench Lathe - 8.5x20

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