BUILD IT RIGHT. KEEP IT FLAT.

Before starting, make sure you have received all your parts and items undamaged from the delivery company. Your delivery should not have been exposed to the elements, double stacked, opened or received any damage. If it has, please refuse delivery and contact us as soon as possible to resolve this with the delivery company.

Lay out all components and familiarise yourself with their positions. Depending on the model purchased, your Self Weld kit will typically include:

• Precision laser-cut table top
• Side panels (side skirts)
• End panels
• Internal strengthening ribs
• Interlocking cross ribs
• Leg plates and leg mounting components where applicable

Do not begin welding until you are satisfied that all parts are present and correctly positioned.

Check over each part individually and lightly de-burr the laser cut interfaces (tabs and slots). The fibre laser leaves small amounts of molten steel (slag) on one side of the steel. A quick, light pass with a flap disc grinder (air or angle) removes it, ensures a tight fit and gives a flat, true finished product. We will try to de-burr your parts for you, but this depends on our workshop load.

Remove any loose debris, contamination or sharp burrs that may prevent components from locating correctly.

Avoid excessive grinding of locating tabs, slots or mating surfaces. These features control the position of the table components, and removing too much material can affect alignment.

Place the table top working face down on trestles, steels or a pallet: something that raises the plate in the four corners (large tables should also be supported in the centre), so you can safely reach the underside to clamp.

Make sure there is nothing underneath the top that could cause it to rock or distort.

The accuracy of the supporting surface is particularly important at this stage, because the table will naturally follow the surface it is assembled against.

Interlock the ribs (the sub-frame cross members) as per the slot arrangement and dry fit them to the top plate. The lengthways and crossways ribs lock together to create the internal support structure of the table.

Work progressively across the table rather than forcing one complete section together at once. If required, use a soft-faced mallet to gently seat components. Do not hammer directly onto precision-machined or visible finished surfaces with a steel hammer.

Once all the ribs are slotted together, square them up so there is equal spacing to the edge of the table top, then check that:

• All ribs are fully seated.
• Rib intersections are correctly engaged.
• Components sit square to the table top.
• Nothing is trapped underneath the assembly.

If your table has side skirts, dry fit them now around the rib structure. This aids construction and squares the sub-frame.

The tabs and locating features should naturally position the components. Use sash clamps or threaded bar to pull the skirt plates tight to the sub-frame, clamping the top plate with the skirt as well, so the panels are fully seated against the table top.

At this stage, do not weld anything.

Before any welding, pull the internal rib structure firmly against the underside of the table top. Use bolts or threaded bar together with the supplied assembly plates (or long bolts, unistrut or something to the same effect) to sandwich the ribs to the top.

Pass the bolt or threaded bar through the table's fixture holes and position the assembly plate so that it bridges the rib underneath. Tighten evenly so the rib is pulled firmly into contact with the top.

Work progressively across the table, clamping the cross sections of the sub-frame throughout. You want no air gap between the top and the ribs, so the more plates the better. The aim is to ensure:

• The ribs are fully seated against the underside of the top plate.
• There are no gaps (visible light) between the ribs and the top.
• The rib structure remains square and correctly located.
• The top plate remains flat against the assembly surface.

Do not overtighten the clamps. They should hold the components firmly together without introducing distortion into the table top. Tighten the clamping points gradually and evenly rather than fully tightening one area before moving to the next.

Once all clamping points are in, inspect the underside and confirm that the ribs are sitting tightly against the top plate before you carry on.

Leave the assembly plates, bolts or threaded bar in position while you tack and weld, removing them only where you need access to a weld point.

With the table clamped up and the fit checked, square up the side skirts and align them to the top plate. Measure diagonally from corner to corner, and measure both diagonals: the two measurements should be equal, or as close as reasonably possible.

Also check:

• Side panels are square to the table top.
• End panels are square.
• Internal ribs are correctly located.
• Ribs are firmly clamped against the top plate.
• The table is sitting flat against the assembly surface.

Make any adjustments now. Once the table is welded, correcting alignment becomes considerably more difficult.

Clamp the sides tight to the top plate with G clamps or similar, then tack the sides to the top before welding any of the ribs. Keep each tack small and controlled, and work around the table rather than concentrating on one area, for example: Front left → Rear right → Front right → Rear left. This spreads the heat evenly and reduces the likelihood of distortion.

Once the sides are tacked, stop and recheck the diagonals, panel squareness, rib alignment, flatness and rib-to-top contact. Small tacks can normally be removed or adjusted relatively easily if anything has moved.

At step 07 the side skirts were only tacked to the top. Once the ribs are welded to the top, weld each rib end to the side plate with a single 15 mm stitch on one side, at every point where a rib meets the inside of a skirt, all round the perimeter.

Then place a single 15 mm stitch at the top edge of each of the four corners.

Keep taking breaks to manage the heat, and keep moving around the table rather than finishing one side before starting the next.

Once the leg plates are welded and the table has cooled, bolt on the legs. On the MidiPRO, each PRO leg fixes with four M16 × 55 bolts, washers and nuts.

Depending on your selected configuration, fit the appropriate:

• Adjustable legs
• Standard castors
• FM heavy-duty castors
• Other MAC Industries leg options

Ensure all fixings are securely tightened, then carefully turn the table over onto its castors or feet.

Move the table into its final working position.

If adjustable feet are fitted, adjust each foot until:

• The table is stable.
• All legs are carrying load.
• The working surface is level.

Do not attempt to pull a table flat using the adjustable feet.

The feet should be used to compensate for the floor surface rather than to correct fabrication distortion.

Before putting the table into service, carry out a final visual and dimensional inspection.

Check:

• Table stability
• Weld quality
• Side panel alignment
• Leg fixings
• Castor operation where fitted
• Overall flatness
• All components are secure

Your MAC Industries welding table is now ready for use.

Your welding table is designed for fabrication, but good working practices will help preserve its accuracy.

Avoid concentrating excessive heat in one area of the table for extended periods.

Where possible, allow very hot components to cool before placing them directly onto the table surface.

Regularly clean weld spatter from the table and fixture holes.

A suitable anti-spatter treatment can also help keep the working surface clean and protect the fixture system.

Self Weld tables are supplied as a fabrication kit and require assembly and welding by the customer.

The final accuracy and flatness of a Self Weld table will depend on several factors including:

• The flatness of the assembly surface.
• Correct clamping of the internal ribs.
• Welding technique.
• Welding sequence.
• Heat input.
• Equipment setup.
• Fabricator experience.

Continuous seam welding is not required or recommended. The table should be assembled using the single 15 mm stitches described in this guide, working progressively from the centre outwards.

For customers requiring a table assembled and welded by MAC Industries, our Ready Made option is available.

If you have any questions during assembly, please contact MAC Industries before proceeding.

Our team can assist with component positioning, assembly sequence and general product guidance. Call 01432 381 233 or email sales@macindustries.co.uk.

MAC Industries
Precision Welding Tables, Tooling & In-House Manufacturing
Made in Herefordshire, UK