Nut Feed Screw Compound: What It Does and How to Apply

By Products for bench top machinists | LittleMachineShop.com | Published: 2026-10-25

Category: How-to Guides

Learn what a feed screw compound is, why it matters for your bench lathe, and a step-by-step guide to applying anti-wear compound to the compound feed screw nut.

Quick answer

A feed screw compound is a specialized anti-wear lubricant for the nut on your lathe's compound feed screw. Applying it reduces friction, prevents premature wear, and keeps your DRO-equipped machine accurate.

Why the compound feed screw nut needs special lubrication

The compound feed screw nut is a small but critical part that translates rotary motion into precise linear movement of the compound slide. On machines with a digital readout (DRO), any play or wear in this nut directly affects positioning accuracy. Standard grease or oil can attract grit and may not provide the anti-wear properties needed for repeated, fine adjustments.

A dedicated feed screw compound is formulated to stay in place, resist contamination, and reduce friction between the screw threads and the nut. This is especially important when you are taking light finishing passes where even a few thousandths of backlash can ruin a part.

When to replace the nut vs. just lubricating

If you already have noticeable backlash (more than 0.005" of free movement) or the compound slide feels rough, lubrication alone may not fix it. The nut itself may be worn. In that case, replacing the nut with a new one—like the Nut, Feed Screw Compound, DRO (part SC4-252)—is the correct first step. After replacement, applying the compound keeps the new nut in good condition and extends its service life.

How to apply feed screw compound to the compound nut

1. Remove the compound slide assembly: Disconnect the DRO sensor arm if present, then unbolt the compound slide from the cross slide. Slide it forward to expose the feed screw and nut. Common mistake: Forgetting to disconnect the DRO arm first can damage the sensor. Always disconnect the DRO arm before unbolting the compound slide.
2. Clean the feed screw and nut threads: Use a degreaser and a stiff brush to remove old grease, chips, and debris from both the screw and the nut. Wipe dry with a lint-free cloth. Checkpoint: If the nut threads look worn or the nut slides loosely on the screw, replace the nut now rather than just relubricating. Replace the nut if threads show wear before applying new compound.
3. Apply a thin, even coat of feed screw compound: Squeeze a small amount of anti-wear compound onto the screw threads—about a pea-sized dollop is enough for a 7x12 or 7x14 mini lathe. Use a clean brush or your finger to spread it evenly along the threaded portion. Common mistake: Over-application causes excess compound to ooze out and attract debris. Use a thin coat; excess compound does more harm than good.
4. Work the compound into the nut: Slide the compound assembly back onto the screw and rotate the feed screw handle by hand through its full travel range several times. This distributes the compound evenly between the screw and nut threads. Checkpoint: If you feel binding or uneven resistance, remove the assembly and check for debris or a damaged nut. Full travel cycling ensures even distribution and reveals binding issues.
5. Reinstall the compound slide and check backlash: Bolt the compound slide back in place, reconnect the DRO arm, and zero the readout. Turn the feed screw handle one full turn forward and back, then check the DRO for any difference. Acceptable backlash for a well-lubricated, unworn nut is under 0.002". Common mistake: Skipping the backlash check can leave unnoticed play that affects cut accuracy. Always verify backlash after reassembly; adjust or replace if over 0.002".

Product fact

Nut, Feed Screw Compound, DRO: The Nut, Feed Screw Compound, DRO is a replacement nut for the compound feed screw on machines equipped with a digital readout (DRO). It is identified by part number SC4-252 and is offered under the Sieg Industrial Group brand. If your compound feed screw nut is worn, this direct replacement restores original fit and accuracy, making it the right part to install before applying fresh lubricant.
Nut, Feed Screw Compound, DRO