Scale Ring Sleeve, Compound Rest 

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

Item No	Models
340	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

Click your model to see the complete parts list.