When selecting weld-in threaded inserts for tubing, compatibility, material strength, and thread compatibility matter most. The following 5 QSC inserts are commonly used in tube projects, offering reliable weld-in performance for various tube ODs, IDs, and wall thicknesses. This guide highlights each product’s specifications, helps compare options, and points out what to consider when choosing the right insert for your application.
| Product | Tube Size | Thread | Wall | Material |
|---|---|---|---|---|
| QSC 1/2-20 RH .083 | 1″ OD | 1/2-20 RH | .083 | 1045 Mild Steel |
| QSC 3/4-16 RH .250 | 1 1/2 OD | 3/4-16 RH | .250 | 1045 Mild Steel |
| QSC 3/4-16 LH .120 | 1 1/4 OD | 3/4-16 LH | .120 | 1045 Mild Steel |
| QSC 5/8-18 RH .120 | 1 1/4 OD | 5/8-18 RH | .120 | 1045 Mild Steel |
| QSC 3/4-16 LH .250 | 1 1/2 OD | 3/4-16 LH | .250 | 1045 Mild Steel |
The products below are among the most relevant welded-in threaded inserts for standard tubing sizes. Each entry includes a brief look at material, tube compatibility, and thread type to help you compare options quickly and select the right fit for your build.
QSC 1/2-20 RH .083 Weld In Bung
Material: 1045 Mild Steel. Fits Tube Size: 1″ OD X .834 ID X .083 Wall. Thread Size: 1/2-20 RH. This insert is designed for weld-in installation in common 1″ tubing, providing a 1/2-20 external thread for compatible fasteners. The .083 wall thickness offers a balance between strength and weight for light to moderate-duty applications.
QSC 3/4-16 RH .250 Weld In Bung
Material: 1045 Mild Steel. Fits Tube Size: 1 1/2 OD X 1.000 ID X .250 Wall. Thread Size: 3/4-16 RH. This heavy-duty weld-in bung is suitable for larger tubing and higher load scenarios, delivering robust attachment points with a threaded 3/4-16 contact. The .250 wall thickness enhances rigidity for structural framing or support arms.
QSC 3/4-16 LH .120 Weld In Bung
Material: 1045 Mild Steel. Fits Tube Size: 1 1/4 OD X 1.010 ID X .120 Wall. Thread Size: 3/4-16 LH. The left-hand thread variant provides an option for specific assembly directions or torque requirements. Suitable for applications where reverse-threaded hardware is necessary for operational safety or design constraints.
QSC 5/8-18 RH .120 Weld In Bung
Material: 1045 Mild Steel. Fits Tube Size: 1 1/4 OD X 1.010 ID X .120 Wall. Thread Size: 5/8-18 RH. This option pairs a moderate wall thickness with a mid-range tubing size, offering a sturdy threaded interface for mechanical assemblies that require regular torque application and reliable fastener retention.
QSC 3/4-16 LH .250 Weld In Bung
Material: 1045 Mild Steel. Fits Tube Size: 1 1/2 OD X 1.000 ID X .250 Wall. Thread Size: 3/4-16 LH. A robust left-hand threaded option for larger tubing and high-load settings, ensuring secure attachment with a long-lasting threaded interface.
QSC 1/2-20 LH .065 Weld In Bung
Material: 1045 Mild Steel. Fits Tube Size: 1″ OD X .870 ID X .065 Wall. Thread Size: 1/2-20 LH. A lightweight variant with a smaller wall, suitable for lighter-duty needs or where space constraints limit material thickness.
QSC 1/2-20 RH .065 Weld In Bung
Material: 1045 Mild Steel. Fits Tube Size: 1″ OD X .870 ID X .065 Wall. Thread Size: 1/2-20 RH. The RH variant with a slim wall is engineered for tight-fit installations where preserving core tube strength while adding threaded capability is required.
QSC 5/8-18 RH .095 Weld In Bung
Material: 1045 Mild Steel. Fits Tube Size: 1 1/4 OD X 1.060 ID X .095 Wall. Thread Size: 5/8-18 RH. A mid-thickness option for tubing approaching 1 1/4″ OD, providing a sturdy threaded interface while maintaining a lighter weight profile than thicker variants.
Buying Guide: Key Considerations And Comparisons
Material compatibility matters most when welding inserts to tubing. All listed QSC inserts use 1045 mild steel, offering good weldability and strength for standard tubing. Choose wall thickness based on load requirements: thinner walls save weight but reduce rigidity, while thicker walls increase strength for higher-load assemblies. Thread size should match your fasteners and torque requirements; common options include 1/2-20, 5/8-18, 3/4-16 LH/RH, and so on. Consider tube outer diameter (OD) and inner diameter (ID) to ensure a proper fit and reliable weld penetration. For tight spaces, select smaller diameter and thinner walls; for structural frames, larger OD and thicker walls provide additional resilience. LH threads are useful in counterintuitive setups or when assembly direction benefits from reverse threading, while RH threads are standard. Accessibility of the threaded portion after installation is another factor; ensure there’s enough tube surface area for a secure weld and a stable nut or bolt engagement. When in doubt, prioritize inserts with documented compatibility for common tubing dimensions and verify fit with a quick test weld before mass production.