Type
Chassis and undercarriage frames for mobile machines
The welded frame of a mobile machine: a chassis tub with cross walls, a ladder frame of two rails and cross members, a subframe that sits on a vehicle chassis, or the centre frame of a tracked undercarriage with a seat for its slew ring. Pivot lugs, bearing bores and mounting pads are what these frames are made for.
In the gallery this type runs from a front chassis of a metre and a half to a tubular space frame over ten metres long. Pairs exist as left and right hands, and a frame is shown either as welded or in its machined state.
What the drawing must show
A part like this is priced from the drawing. The quotation is fastest when it carries:
- The bore positions and tolerances for every pivot and bearing seat, and whether they are machined after welding
- The welded envelope and the machined envelope, if they differ
- Plate thicknesses and section sizes with the material grade
- Weld symbols on the lugs and the main joints, and the inspection level
- The finish, and which bores and faces stay unpainted
16 models of this type
Real structures that came through this company as built jobs, quoted enquiries or designs from our own office, shown as anonymous models with their measured size. Open one for its description.
- Overall size, L x W x H
- 10 447 x 2 487 x 2 132 mm
A tubular space frame chassis built from square hollow section rails and cross braces, with flat plated deck sections and four curved, plated wheel arches running along its length. One end carries a tall, multi-level tube cage with mounting brackets and lugs, the other stays low and open. It measures about 10.4 m long, 2.5 m wide and 2.1 m high. Such parts are tack welded on a fixture and welded out, then checked against the drawing with the measuring arm.
- Overall size, L x W x H
- 3 669 x 2 300 x 1 977 mm
A welded chassis frame built from plated side walls, box section rails and a tall upright tower of ribbed plates at one end, tied across by a box cross member. A curved top edge sweeps over the tower, with bored holes, slotted lugs and machined pads set along the rails and side plates. It measures about 3.7 m long, 2.3 m wide and 2.0 m high. A part like this is welded out on a fixture, with the bores and pads machined after welding.
- Overall size, L x W x H
- 5 590 x 1 195 x 797 mm
A ladder chassis frame of this kind is formed from two long rails tied together by cross members, with boxed ends, gusseted brackets and a dropped mounting assembly hung under the middle. Rows of bored holes and small welded lugs line the rails for fittings. The boxed end plates and the stepped bracket under the centre stand out most. It measures about 5.6 by 1.2 by 0.8 m. A piece like this is tacked up on a fixture and welded through, with every bore and pad cut after welding.
- Overall size, L x W x H
- 6 940 x 1 157 x 383 mm
A long subframe built from two parallel rails joined by regular cross members, with a boxed end section and a lighter open frame at the other end. Rows of small mounting brackets line both outer rails, with a couple of upright locating pins standing near each end. It measures about 6.9 m long, 1.2 m wide and 0.4 m high. Pieces like this are welded out on a fixture, with the bores and pads machined after welding.
- Overall size, L x W x H
- 4 365 x 1 480 x 462 mm
A carrier frame built from two deep box section side rails, their webs punched with long rows of drilled holes, linked by three box cross members and a lighter diagonal lower rail pair. Short stub ends and small mounting lugs project at each corner. The frame measures about 4.4 by 1.5 m, standing roughly 0.5 m high. A part like this is tack welded on a fixture and welded out, with the bores and pads machined after welding.
- Overall size, L x W x H
- 2 319 x 1 606 x 2 294 mm
A rear chassis weldment built from folded plate panels, box-section uprights and a tall curved guard hoop braced by diagonal stays. The faceted plated floor carries mounting eyes and lugs on the side plates, with small bores and a bracket set into the lower corner, plus a machined pad beneath the hoop base. It measures about 2.3 m long, 1.6 m wide and 2.3 m high. In this hall a part like this is tacked up on a fixture and welded through, with every bore and pad cut after welding.
- Overall size, L x W x H
- 2 310 x 1 990 x 630 mm
A welded chassis tub formed from folded steel plate, with deep side walls, cross walls, bored mounting pads and lugs, and a slotted vent panel in one corner. A twin-eared bracket with bored holes rises at the centre, flanked by ribs, with a small step tread at the back. It measures about 2.3 by 2.0 m, 0.6 m high. Pieces like this are tacked up on a fixture and welded through, laser cut up to 20 mm and folded over 6 050 mm on the press brake.
- Overall size, L x W x H
- 2 656 x 1 577 x 1 380 mm
A welded chassis housing with a stepped top deck plate with round cut-outs and studs, slotted side walls, internal ribs and a floor plate with a mounting lug. One end opens into a large pocket, the other carries a folded nose panel. The bored, studded deck stands out. It measures about 2.7 by 1.6 by 1.4 m. In this hall a part like this is cut from plate on the laser bed and tacked up on a fixture and welded through.
- Overall size, L x W x H
- 3 770 x 2 159 x 506 mm
A ladder frame with side brackets forms two long rails joined by several cross tubes, with folded end plates, hanging lugs and rows of hook ended brackets running along both sides. The crossed centre brace and the hook fronted end beams stand out against the open rail bays. It measures about 3.8 m long, 2.2 m wide and 0.5 m high. Pieces like this are set on a fixture, tacked and welded out, with every bore and pad cut after welding.
- Overall size, L x W x H
- 2 119 x 1 808 x 357 mm
A centre frame of two long box rails ending in ring lugs, braced by cross tubes into an open ladder grid. Plated pivot brackets with bored and slotted holes hang below one corner, next to a smaller folded bracket, while mounting holes run along both rails. It measures about 2.1 m long, 1.8 m wide and 0.4 m high. A part like this is set on a fixture, tacked and welded out, with every bore and pad cut after welding.
- Overall size, L x W x H
- 1 573 x 1 541 x 318 mm
An undercarriage centre frame built around a flat plated deck with a machined, bolted ring seat at its core. Tapered box section legs are stiffened with ribs and gussets, with clevis lugs and bored pivot holes at the front and mounting holes around the sides. The bored ring seat is the clear focal point. It measures about 1.6 by 1.5 m and stands 0.3 m high. A piece like this is set on a fixture, tacked and welded out, with the bores and pads machined after welding.
- Overall size, L x W x H
- 1 920 x 1 614 x 357 mm
An upper carriage frame built around a rounded drilled floor plate, with two tall webs running lengthwise, cross plates, mounting pads and gusseted brackets tying the structure together. A machined pivot boss with a bored seat sits at the front, flanked by further bored holes and stiffening ribs linking the webs to the deck. It measures about 1.9 m long, 1.6 m wide and 0.4 m high. A piece like this is tack welded on a fixture and welded out, then machined after welding on a horizontal boring mill.
- Overall size, L x W x H
- 1 655 x 1 286 x 338 mm
A welded chassis frame of folded plate side rails and cross members, with a large central opening, bored lugs, mounting pads and small brackets along both sides. The ring of bores and bushings in the base plate and the twin lifting eyes at the front stand out. It measures about 1.7 by 1.3 m and stands 0.3 m high. Such parts are welded out on a fixture, with every bore and pad cut after welding.
- Overall size, L x W x H
- 1 513 x 1 120 x 440 mm
A front chassis weldment made from folded plate walls around a wide oval opening, with a tubular end frame and rows of bolted holes along the top edges. One end carries a raised bracket with a bored bearing seat, the other fans into layered mounting plates with multiple bores. It measures about 1.5 m long, 1.1 m wide and 0.4 m high. Such parts are welded out on a fixture, laser cut up to 20 mm and bent on the 400 t press brake.
- Overall size, L x W x H
- 1 656 x 982 x 289 mm
A welded chassis frame of folded plate rails, cross members and gusseted ribs, with pivot lugs, a bored eye at each end and smaller bracket plates along the deck. A curved wheel arch cutout, machined pivot bores and rows of bolt holes across the deck stand out. It measures about 1.7 by 1.0 m and stands about 0.3 m high. A piece like this is tack welded on a fixture and welded out, cut from plate on the laser bed and bent on the 400 t press brake.
- Overall size, L x W x H
- 1 513 x 982 x 279 mm
A low welded chassis frame of this kind combines folded plate, box section rails, ribs, gussets and mounting brackets into a compact undercarriage. Bored lugs sit at the corners for pivot or axle seats, while flat machined pads and bored faces run along the rails for bearings and mounts, with cut-outs and tabs for fittings throughout. It measures about 1.5 m long, 1.0 m wide and 0.3 m high. A piece like this is welded out on a fixture, with every bore and pad cut after welding.
Each model is rendered from its own geometry in raw steel, without paint, and is shown as a still. Customer names, machine designations and drawing numbers are not published; part lists and files are not offered. The interactive model above this section is a parametric example, not one of these.
How a part like this goes through the hall
Side plates and webs are laser cut up to 20 mm and folded on a 400 t press brake over 6 050 mm where the drawing folds instead of welds. The frame is set on a jig, tack welded, then welded out. Bores and pads are machined after welding on a boring mill with 6 200 x 3 000 x 1 600 mm of travel, so the geometry is cut from the welded piece and not from parts that move. The frame is blasted, painted and measured.
Where this fits
Capabilities it runs through
Industries that order it
Notes from the blog
Other types in this group
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