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Automotive Tube Parts | Door Frames, Racks and Guard Bars | Ø4–150 mm

We bend and weld door frames for beach buggies, kart buggies and patrol vehicles, roof ladder racks and luggage racks, front guard bars, bull bars and pannier frames, and the small charging-cable hooks that go on an electric vehicle. Tube from Ø4 to Ø150 mm, wall 0.8–5 mm, in aluminium 6061 and 6063, 304 stainless or carbon steel, welded to laser cut plates. Made to your drawing in Panyu, Guangzhou since 2013. Prototypes in 3 days with tooling already on the rack; production runs in 25–40 days.

What is on this pageParts that bolt onto a vehicle — not the parts that make it go, stop or steer.

Material	Aluminium 6061 and 6063; some tempers are annealed before bending, decided per part rather than per order. 304 stainless where the part stays unpainted. Carbon steel, painted or powder coated.
Typical parts	Door frames for beach buggies, kart buggies and patrol vehicles; roof ladder racks; luggage racks; front guard bars and bull bars; pannier and side case frames; charging-cable hooks.
What decides acceptance	Hinge and latch hole positions, whether the frame lies flat against the body, whether a left and a right part match, and the coating on the face the buyer sees.
Tooling	Sample in 3 days with a die already on the rack. A new radius adds about two weeks. A welding fixture is built on the first order and stays with the job.
Documents	No IATF 16949 and no PPAP. EN 10204 3.1 is available on request and is issued by the steel or aluminium mill, not by this workshop.

The document row decides whether a job is possible at all, and it is cheaper to read it before the drawing is sent. The full list of what is and is not held is on the documents page.

A door frame is a flatness problem before it is a bending problemOne plane, four corners, and a door that has to close afterwards.

A door frame is bent as a loop, welded at the corners, and then judged by whether the four corners still sit on the same plane. Two things move it out of plane: springback left in each bend, and weld pull at the corners. Both are handled with fixtures and with the order of operations — not by bending more carefully.

The loop closes on itself — the last bend has to meet the first. Springback accumulates over every bend in a loop, so the closing gap is measured on the fixture, not judged by eye on the bench.
Holes are cut before welding — hinge, latch and mounting holes are laser cut in the plate while the plate is still flat, then located by the fixture. Drilling after welding means drilling through a frame that has already moved.
Wall thickness sets the bend — below about 1 mm in aluminium the tube needs a mandrel, and the outside of the bend still thins. Wall from 0.8 mm is bent here; a radius too tight for the wall is reported in the first reply rather than found in the sample.
Both sides off one die — a left and a right frame are bent on the same die and welded in the same fixture, because a pair that differs by two millimetres will not hang straight on the vehicle.

What the bend does to the wall, and what tolerance is realistic at a given radius, is set out on bending tolerances. The forming range itself is on the tube bending page.

Three parts from this groupA frame, a bar and a long rack: same machines, three different failure modes.

Welded aluminium car door frame made from bent tube and formed plate — An aluminium door frame in one plane, tube welded to formed plate. The four corners are what the fit is judged on.

V-shaped tubular car bull bar with laser cut side plates, gloss black — V-shape bar with laser cut side plates — tube and plate combined in one assembly, coated after welding.

Tubular roof ladder rack welded from bent round tube — Roof ladder rack. A part this long shows any twist the moment it is laid on a flat surface.

Racks, hooks and the small partsNot everything in this group is a bar you can see from outside the vehicle.

Roof ladder racks — welded tubular frames long enough that straightness over the full length is the real check, not the individual bends.
Luggage racks — a bent tube frame welded to a laser cut perforated plate, so one part carries four processes: cut, bend, weld, coat.
Pannier and side case frames — bent tube with welded mounting tabs; the tab position decides whether the case hangs straight.
Charging-cable hooks for electric vehicles — a small bent tube hook on a laser cut mounting plate. Fixed geometry, so the sample is quick; what takes the time is agreeing the fixing method and the coating.
Guard bars and bull bars — bent tube with welded brackets and laser cut side plates. These are untested accessories, not crash protection.

Motorcycle crash bars, engine guards and motorcycle racks are on the motorcycle page. The two pages are split because the acceptance criteria differ: a bike part is judged as a visible pair, a vehicle frame as a flat assembly.

Limits — what we will not take onVehicle work attracts questions this workshop cannot answer, and it is cheaper to say so here.

No IATF 16949 and no PPAP. We are not a production supplier to a vehicle assembly line. Aftermarket accessories, special vehicles, prototypes and small series are what this page covers.
No safety-critical structure. No crash management parts, no seat belt anchorages, no suspension, steering or brake components.
No fitment list. We make to your drawing or sample. Which model year a part fits is your judgement, not ours.
No other company's trademark. We do not stamp, mould or print a vehicle brand on a part, and we do not photograph customer branding.
No complete vehicles and no homologation paperwork. Parts only.
Bending stops at Ø150 mm. Larger tube can be cut here, not bent.
Finish is chosen by you. Grinding, sandblasting and the electrolytic wash are done here; plating and powder coating go to an outside finishing shop, or to yours if you prefer to keep that step in-house.
No price without a drawing. Tube size, wall, bend count and quantity all move the figure.

Guard bars and bull bars on this page are untested accessories, not certified crash or rollover protection devices. Fitment and local vehicle regulations remain the buyer's responsibility.

General information only — not engineering advice. Suitability for a specific application, load case or service environment must be confirmed by the buyer's engineer.

Questions from accessory brands and vehicle builders

Can you make door frames for a beach buggy or a patrol vehicle?

Yes — that is the part this page is built around. The frames are welded from bent tube and formed plate in 304 stainless or 6061/6063 aluminium, and the corner welds are made in a fixture so the four corners stay coplanar. Wall from 0.8 to 5 mm. Below about 1 mm in aluminium the tube is bent on a mandrel, and if the radius is too tight for the wall that is said in the first reply rather than discovered in the sample.

Which aluminium grades do you bend?

6061 and 6063 tube, from Ø4 to Ø150 mm outside diameter. Some tempers crack at the bend and are annealed first. Whether a particular heat treatment needs it is decided per part, and it is not something a drawing usually states — send the grade and the radius and it is answered with the quotation.

Can you supply parts to a vehicle assembly line?

No. We do not hold IATF 16949 or PPAP, so we are not a production supplier to a vehicle assembly line. Aftermarket accessories, special-purpose and low-volume vehicles, prototypes and spare parts are what this page is for.

Do you make charging-cable hooks for electric vehicles?

Yes — a bent tube hook welded to a laser cut mounting plate, then coated. It is a small part with a fixed geometry, so the sample is quick. The time goes on agreeing the fixing method and the coating rather than on the bending.

What is the smallest order?

One piece, so the fit can be checked before a batch is committed. A new radius or a new welding fixture adds about two weeks at prototype stage; the part itself is 3 days once the tooling exists.