Home / Cutting, Welding and Fit Up on the Shop Floor
Cutting, Welding and Fit Up on the Shop Floor
The middle of a gate build happens on the shop floor in three linked steps: cutting every member to length, fitting the pieces together on a flat table, and welding them into a rigid frame. Fit-up, the step between cutting and welding, decides whether the finished leaf is square, flat and the right size, so it gets the most care from a good welder and the least attention from most customers.
Cutting to the drawing
Work starts from the approved drawing, which lists each rail, picket, post and plate with a length. Steel arrives in long stock lengths, and the shop cuts it with a chop saw, a band saw or a cold saw, depending on the size of the tube. Cuts for square corners are made straight. Cuts for angled joints, such as an arched top or a raked bottom rail, are mitered or coped so the pieces meet cleanly.
Accuracy matters here because small errors add up. A picket cut an eighth of an inch long looks harmless, but forty of them in a row can push a frame out of square. Fabricators often set a stop on the saw so every repeated piece comes out the same, and they check the first piece against the drawing before cutting the rest.
Cleaning and preparing edges
Fresh cuts leave burrs and sharp edges. Pieces are deburred with a grinder or file so they fit tight and so no one gets cut later. Mill scale, the dark flaky layer on new hot rolled steel, may be ground off where welds will go, since scale makes welds weaker and messier. Surfaces that will be welded need to be bare metal, free of oil and rust, or the weld can trap gas and develop holes.
Laying out on the table
Fit-up happens on a heavy, flat steel table, often marked with a grid. The welder lays the rails and posts out in their final positions, usually working from a full size layout or from stops and clamps fixed to the table. The goal is to hold every piece exactly where it belongs before any heat is applied. Magnetic squares, clamps and spacers keep corners at ninety degrees and keep picket spacing even.
Flatness matters as much as squareness. If the table is not flat, or if the pieces are not pressed down evenly, the leaf can come out twisted, with one corner higher than the others. A twisted gate will rub, bind or sag, and no amount of adjusting hinges fully fixes it. This is why shops invest in a good table and why a careful welder checks flatness before locking anything in.
Tack welds first
Before the real welds go in, the welder places small tack welds at each joint. These hold the layout in place but can still be broken and corrected. After tacking, the frame is measured again: diagonals are compared to confirm it is square, overall width and height are checked against the drawing, and the leaf is lifted slightly to see that it sits flat. Only when these checks pass does full welding begin.
It is a normal part of the process to adjust at this stage. A tack weld can be cut with a grinder and redone in a minute. A finished weld cannot be fixed nearly so easily, so the extra checking is cheap insurance.
Full welds and heat
Steel expands when heated and shrinks as it cools, and a weld pulls on the pieces around it. A long weld along one side of a frame can bow the whole piece. Experienced welders manage this by alternating sides, welding in short sections and letting metal cool between passes. They also sequence the welds so that pulls on one side are balanced by pulls on the other.
Common processes include MIG welding, which feeds wire continuously and is fast for steel frames, and TIG welding, which is slower and gives very clean, precise welds often used on decorative work or thin material. Stick welding is used less often on gates but is common for heavy structural pieces. Which process the shop uses depends on the material, the thickness and the look wanted.
Grinding and finishing the welds
After welding, the joints are usually ground smooth so they blend into the surface. How much grinding is done depends on the style. A rustic or industrial look may leave beads visible. A clean modern gate usually has welds ground flush, so after coating you cannot see where one piece ends and another begins. This step takes a lot of labor, and it is one reason two gates of similar size can differ in price.
Spatter, small beads of molten metal thrown off during welding, is chipped or ground away as well. Left in place, it creates bumps under the finish and snags clothing or hands.
Attaching hardware mounts and decorative parts
With the main frame complete, the shop adds the parts that make it a gate: hinge mounts or barrel hinge pieces, latch plates, drop rod receivers, gate stops, and any decorative elements such as scrolls, rings or cut panels. The positions come from the drawing and from measurements taken at the site visit. If a lock or operator bracket is part of the plan, its mounting plate is added now, because drilling or welding after coating would damage the finish.
Decorative pieces are welded or bolted in a way that holds up to years of weather and the occasional push from a delivery driver. The shop considers the load on each piece, since a thin ornament can fatigue and crack if it carries weight it was not meant to.
Checks before the frame leaves the table
Before sending the gate for finishing, a careful shop measures once more. Overall dimensions, diagonals, flatness and hardware locations all get verified against the drawing. Many shops also hang the leaf on a test post or lay it against a jig to check the swing and the latch alignment. Catching a mistake now costs minutes. Catching it after coating costs a new finish.
If you are able, ask to see the gate at this stage. A frame in bare steel shows every weld and every detail, and it is the last time you can ask for a change without redoing the coating. The next step, getting a finish onto the steel, is covered in the article on material orders and powder coat queues, and the wider story is told in the guide to how a gate gets built inside a fabrication shop.
What good work looks like
A well made frame sits flat on a level surface without rocking. Its diagonals measure the same within a very small tolerance. Welds are consistent in size, with no gaps, cracks or holes. Edges are smooth and corners are clean. Pickets are evenly spaced and plumb. Hardware mounts are solid and square to the frame.
These details are easy to check by eye and by hand, and a shop proud of its work will be glad to point them out. When you see them, you can feel confident that the structure underneath the finish will hold up long after the paint and coating have done their job.