Burrs Appearing on a Rebar Thread Rolling Machine? Don’t Panic! 4 Major Causes + Practical Solutions — Even Beginners Can Fix It.

At rebar processing sites, rough threads and burrs are not minor issues. They can cause couplers to jam during installation, lead to uneven load transfer in the connection, and even cut workers’ hands.

In fact, problems like these don’t require “experienced workers relying on intuition” to fix. As long as you identify the root cause, the issue can be solved quickly. After reading this guide, you’ll be able to handle it with confidence.

Be Alert First!

Three Major Hazards of Burrs and Rough Threads

1. Affects connection quality
Burrs prevent the rebar and coupler from fitting tightly together. Under load, the connection may loosen, creating potential structural safety risks.

2. Slows down construction efficiency
Rough threads increase resistance when tightening couplers. A connection that normally takes 10 seconds may require 30 seconds or more with repeated adjustments.

3. Increases safety risks
Sharp burrs can easily tear gloves or cut skin. During high-volume processing, workers must operate with extra caution.

Find the Root Cause!

Four Common Reasons (All Easy to Check)

1. Cutting Tools Not Performing Well – The Most Overlooked Factor

• Worn rib-stripping blades (edge damage exceeding 0.2 mm) or improper installation can cause uneven rib removal, which leads to burrs during threading.

• Worn thread rolling dies (edge damage exceeding 0.2 mm) or incorrect installation can also produce rough threads and burrs.

2. Improper Operation – Small Details Matter

• Misaligned clamping of rebar (deviation from the spindle axis greater than 1 mm) causes uneven force during rolling, leading to burrs on one side.

• Metal chips not cleaned properly: leftover chips from rib stripping or threading can get trapped in the dies or clamps and scratch the thread surface during the next operation.

3. Poor Raw Materials – Bad Material Means Poor Results

• Rebar with heavy scale or rust (thickness exceeding 0.1 mm) may not be completely removed during rib stripping, leaving residue on the threads after rolling.

• Excessively hard rebar can damage the thread rolling dies, resulting in burrs on the finished threads.

4. Insufficient Lubrication – No Oil Means Dry Friction

• Incorrect lubricant type: under high-temperature rolling, the oil film may break down, increasing metal friction and producing burrs.

• Insufficient oil supply: inadequate lubrication at the dies or rib-stripping blades causes dry grinding and rough thread surfaces.

Quick Solutions

Practical Fixes You Can Apply Immediately

1. Tool Issues: Replace + Recalibrate

• Replace rib-stripping blades immediately if the cutting edge is chipped or excessively worn. Use a square to ensure the blade is perpendicular to the rebar axis during installation.

• Replace worn thread rolling dies (select models matching the rebar specification). Before installation, clean metal chips from the die grooves with alcohol and refill the machine with sufficient emulsified oil.

2. Operational Issues: Align + Clean

• Align the rebar properly: after placing it in the clamp, gently shake the end. If displacement exceeds 0.5 mm, realign it before starting the machine.

• Remove metal chips regularly: stop the machine and clean the rolling dies and stripping blades with a brush after processing every 10 rebars to prevent accumulation.

3. Raw Material Issues: Pre-treat + Screen

• Rust removal: remove rust using a wire brush, or soak the rebar in 15% hydrochloric acid for 5 minutes, then dry it.

• Material selection: check the hardness of incoming rebars. Avoid using materials exceeding 25 HRC, and prioritize rebars with smooth surfaces and minimal scale.

4. Lubrication Issues: Control Oil Supply + Replace Regularly

• Use dedicated emulsified oil for thread rolling machines. When the oil changes from milky white to black after circulation, it should be replaced. Clean impurities from the oil tank before refilling.

• When the machine starts, the oil outlet pipe should spray emulsified oil toward the machine head, lubricating the blades and dies while flushing away debris. The oil should be mixed with water (for example, 150 ml oil with 200 ml water for the initial mixture).

Tips to Avoid Problems

Two Quick Daily Checks

• Before starting the machine: check the rib-stripping blades and rolling dies. If they feel dull or have burrs, replace them. Add a few drops of oil to ensure proper lubrication.

• After the first piece: inspect the thread surface of one processed rebar. If it feels smooth to the touch and shows no visible scratches, you can proceed with batch production.

Let’s Talk

Have you ever encountered burr problems during rebar threading?
Did you solve it by replacing the tools or adjusting machine parameters?

Share your experience in the comments so others can avoid the same problems!