Product Description
Threaded Round Tube Inserts are engineered to slide tightly into commercial round steel or aluminum tubing. They provide a rigid, non-loosening internal metric or imperial thread to securely mount adjustable leveling feet, screw-in casters, and structural furniture glides.
Structural Performance
Heavy-Gauge Integration: Manufactured from precision cold-rolled or pressed carbon steel with dense internal threads that prevent stripping under high torque.
Knurled & Flanged Anchoring: Outer surface features engineered knurled patterns or expansion ribs to establish a permanent friction fit inside the tube, eliminating spinning or slide-out.
Anti-Corrosion Surface: Finished with electro-zinc plating or black oxide treatment exceeding 8 micrometers in thickness to withstand moisture and industrial washdowns.
Flush Structural Fit: Features a precise perimeter flange that sits perfectly flush against the raw cut-edge of the metal tube, concealing sharp burrs.
High Axial Capacity: Structural steel wall thickness is rated to support heavy static loads without collapsing or deforming inside the hollow tubing.
Threaded round tube inserts
|
Platform material |
Steel / Zinc plated (Cr3+) |
Steel / Zinc plated (Cr3+) |
|
Clip material |
Steel / black oxide |
Steel / black oxide |
|
Tube thickness |
16-18ga (≒1.2-1.5mm) |
16-18ga (≒1.2-1.5mm) |
|
Clip Qty |
Single clip |
Double clips |
|
Mounting Type |
Thread stem mount |
Thread stem mount |
|
Min. order |
5,000 pieces |
5,000 pieces |
|
Trade term |
FOB Taiwan |
FOB Taiwan |
Specifications
Single clip star-type thread inserts
|
Inch Thread |
Metric Thread |
Part no. |
Outside dimension of the tube |
|
|
1/4-20 |
M6-P1.0 |
S305-19B14 (M6) |
19mm / 0.75 inch |
|
|
S305-22B14 (M6) |
22mm / 0.875 inch |
|||
|
S305-25B14 (M6) |
25mm / 1 inch |
|||
|
S305-28B14 (M6) |
28mm / 1.125 inch |
|||
|
S305-32B14 (M6) |
32mm / 1.25 inch |
|||
|
S305-38B14 (M6) |
38mm / 1.5 inch |
|||
|
S305-44B14 (M6) |
44mm/ 1.75 inch |
|||
|
S305-50B14 (M6) |
50mm /2 inch |
|||
|
Inch Thread |
Metric Thread |
Part no. |
Outside dimension of the tube |
|
|
5/16-18 |
M8-P1.25 |
S305-19B516 (M8) |
19mm / 0.75 inch |
|
|
S305-22B516 (M8) |
22mm / 0.875 inch |
|||
|
S305-25B516 (M8) |
25mm / 1 inch |
|||
|
S305-28B516 (M8) |
28mm / 1.125 inch |
|||
|
S305-32B516 (M8) |
32mm / 1.25 inch |
|||
|
S305-38B516 (M8) |
38mm / 1.5 inch |
|||
|
S305-44B516 (M8) |
44mm/ 1.75 inch |
|||
|
S305-50B516 (M8) |
In50mm /2 inch |
|||
|
Inch Thread |
Metric Thread |
Part no. |
Outside dimension of the tube |
|
|
3/8-16 |
M10-P1.5 |
S305-22B38 (M10) |
22mm / 0.875 inch |
|
|
S305-25B38 (M10) |
25mm / 1 inch |
|||
|
S305-28B38 (M10) |
28mm / 1.125 inch |
|||
|
S305-32B38 (M10) |
32mm / 1.25 inch |
|||
|
S305-38B38 (M10) |
38mm / 1.5 inch |
|||
|
S305-44B38 (M10) |
44mm/ 1.75 inch |
|||
|
S305-50B38 (M10) |
50mm /2 inch |
|||
Double clips star-type thread inserts
|
Inch Thread |
Metric Thread |
Part no. |
Outside dimension of the tube |
||
|
1/4-20 |
M6-P1.0 |
D305-19B14 (M6) |
19mm / 0.75 inch |
||
|
D305-22B14 (M6) |
22mm / 0.875 inch |
||||
|
D305-25B14 (M6) |
25mm / 1 inch |
||||
|
D305-28B14 (M6) |
28mm / 1.125 inch |
||||
|
D305-32B14 (M6) |
32mm / 1.25 inch |
||||
|
D305-38B14 (M6) |
38mm / 1.5 inch |
||||
|
D305-44B14 (M6) |
44mm/ 1.75 inch |
||||
|
D305-50B14 (M6) |
50mm /2 inch |
||||
|
Inch Thread |
Metric Thread |
Part no. |
Outside dimension of the tube |
||
|
5/16-18 |
M8-P1.25 |
D305-19B516 (M8) |
19mm / 0.75 inch |
||
|
D305-22B516 (M8) |
22mm / 0.875 inch |
||||
|
D305-25B516 (M8) |
25mm / 1 inch |
||||
|
D305-28B516 (M8) |
28mm / 1.125 inch |
||||
|
D305-32B516 (M8) |
32mm / 1.25 inch |
||||
|
D305-38B516 (M8) |
38mm / 1.5 inch |
||||
|
D305-44B516 (M8) |
44mm/ 1.75 inch |
||||
|
D305-50B516 (M8) |
50mm /2 inch |
||||
|
Inch Thread |
Metric Thread |
Part no. |
Outside dimension of the tube |
||
|
3/8-16 |
M10-P1.5 |
D305-22B38 (M10) |
22mm / 0.875 inch |
||
|
D305-25B38 (M10) |
25mm / 1 inch |
||||
|
D305-28B38 (M10) |
28mm / 1.125 inch |
||||
|
D305-32B38 (M10) |
32mm / 1.25 inch |
||||
|
D305-38B38 (M10) |
38mm / 1.5 inch |
||||
|
D305-44B38 (M10) |
44mm/ 1.75 inch |
||||
|
D305-50B38 (M10) |
50mm /2 inch |
||||
Production Automation & Quality Validation
Operating from our automated Hua-tan facility, we manage the entire metal forming and threading process. Each batch undergoes:
Optical Thread Sorting
100% automated camera checks ensure zero thread pitch deviations and eliminate cross-threading risks.
Axial Pull-Out Testing
Hydraulic test rigs measure the maximum pull-out force required to dislodge the insert from matching metal tubing.
Salt Spray Validation
Randomly selected components undergo 24-hour neutral salt spray testing (ISO 9227) to verify anti-rust performance.
How to install it?
Packaging Safety & Transit Protocols
Heavy-Duty Packing: High-density steel components are packed with moisture-resistant desiccant bags inside five-layer BC-flute corrugated boxes to prevent transport damage.
Palletized Delivery Security: Cartons are stacked on ISPM-15 compliant pallets, secured with reinforced strapping and multi-layer stretch film.
Global Shipping: Direct coordination under FOB (China ports), CIF (destination ports), or door-to-door DDP.
Why Choose Bai Ye Industrial
50-Year History
Founded in 1975, we have 50 years of expertise in steel pressed tube metal adapters and custom plastic injection molding.
Automated Capacity
Our upgraded Hua-tan facility (since 2015) utilizes advanced automatic machines to ensure high capacity and strict dimensional control.
25 Years Exporting
Since 2001, our international trade department has provided 25 years of reliable global logistics and OEM/ODM services.
SGS Certified
An ISO 9001:2015 certified factory with products fully passing SGS testing for RoHS, California Prop 65, and BIFMA standards.
FAQ
Q: How do you ensure the adapter creates a tight fit and does not spin when screwing in a caster?
A: We machine specific outer knurling or expansion ribs that bite directly into the interior wall of the round tube. Once hammered or pressed into position, the internal friction prevents the adapter from spinning or backing out during caster installation.
Q: What is the most critical dimension needed to ensure a perfect fit into our tubing line?
A: We need two precise measurements: the exact Outer Diameter (OD) of your round tube and the Wall Thickness (or internal diameter). This allows us to calibrate the insert's outer diameter to achieve an ideal interference fit without splitting your tube.
Q: Can your threaded adapters handle heavy industrial applications like medical carts or warehouse shelving?
A: Yes. For heavy-duty applications, we manufacture thick-walled inserts from solid steel blocks or heavy-gauge Q235 steel. These variants distribute the vertical weight across a wider internal surface area, allowing high load capacities.
Q: Do you offer stainless steel options for food service or outdoor environments?
A: Yes. For environments requiring strict hygiene or moisture resistance, we produce inserts using grade SUS304 or SUS316 stainless steel, offering natural resistance to rust and harsh chemical cleaners.
Q: What is your factory's standard lead time for a custom thread size or diameter run?
A: If we use our existing tooling, the standard production lead time is 20 to 30 days. For completely custom tube dimensions requiring new stamping dies, an additional 10 to 12 days is required for initial tool fabrication and sample verification.
Q: Can these adapters be used on automated assembly lines in our furniture factory?
A: Yes. Because we maintain thread and outer dimensional tolerances within +/- 0.05mm through automated thread tapping and optical sorting, our inserts are perfectly suited for automated pneumatic press-fitting machines.
Q: Do you provide bulk pricing discounts and free pre-production samples for evaluation?
A: Yes. We support global OEM procurement by offering tiered volume pricing. We can provide standard catalog samples free of charge for your engineering team to test fit and load capacity prior to contract orders.
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