Arrow Side Welding: How to Read the Arrow Side vs Other Side of a Welding Symbol

What “Arrow Side” Actually Means in Welding

You are holding a print in one hand and a stinger in the other. The symbol shows a little arrow pointing at the joint, and somewhere in that tangle of lines is the answer to a deceptively simple question: which face of this joint gets welded? In welding, that answer lives in two words — arrow side and other side.

Here is the plain-English version. The arrow side is the side of the joint the arrow points to. The other side is the side opposite the arrow side. That is the whole convention, and once it clicks, misread symbols stop being a problem.

Every Joint Has Two Sides

According to ANSI/AWS A2.4, the standard for welding, brazing, and nondestructive examination symbols, any welded joint indicated by a symbol will always have an “arrow side” and an “other side.” This is not optional bookkeeping — it is built into the system’s logic. The moment you draw an arrow at a joint, you have defined a near side and a far side, even if the weld goes on only one.

The current edition, AWS A2.4:2020, refines how those symbols are drawn, but the core two-sided framework has been stable for decades. You can see the same logic in the widely reproduced AWS weld symbol chart used on shop floors, and the ANSI blog notes the 2020 revision mainly reorganizes and clarifies the standard rather than overturning the convention.

The Three Location Conditions

Across the standard, symbol placement resolves into three location conditions:

• Arrow side — the weld goes on the side the arrow points to.
• Other side — the weld goes on the side opposite the arrow.
• Both sides — welds are specified on both faces of the joint.

Notice what is missing: the drawing view, bench position, or “wherever the welder is standing.” None of those matter. The joint itself is the basis of reference in the AWS symbol system, not the drawing view or the fabricator’s position. That single rule is why a symbol reads the same whether a part is shown in plan, elevation, or section, and why two welders on opposite sides of a fixture should interpret the same arrow identically.

Why the Joint — Not the View — Is the Reference

Think about a lap joint on a bracket. From above, the joint looks like a plain rectangle; from the end, like a step. A drawing may show one view, but the weld exists in three-dimensional space, and the arrow indicates a face of that real joint. Anchoring reference to the joint keeps the symbol honest across every view and every workstation.

This matters for inspection, too. An inspector reading the same print applies the same convention, so “arrow side” becomes a shared language between designer, fitter, and welder rather than a guess. Get it wrong and you can weld the wrong face, double your work, or fail acceptance.

What This Section Sets Up

From here, we will decode the symbol piece by piece — the arrow, the reference line, and the tail — then work through arrow-side placement on T, lap, butt, and corner joints, how groove and fillet welds differ, and the special case of the broken arrow. We will also compare AWS A2.4 with ISO 2553, since the two standards handle arrow-side logic differently — mixing them up is a classic error.

If you are building shop-floor habits alongside this, our guide to building real welding skills through deliberate practice is a good companion, and knowing your machine’s setup — like the polarity covered in our TIG polarity guide — keeps the mechanics straight while the print tells you where to put metal. For safety at the bench, the OSHA welding and cutting guidance is a reliable baseline.

Note: Keep one rule in your head before everything else: the arrow defines the arrow side, and the joint is the only reference that counts. Everything that follows rests on that foundation.

Anatomy of a Welding Symbol: The Arrow, Reference Line, and Tail

Before you can judge which side of a joint gets the weld, you need to know what you’re actually reading. Most confusion about arrow side welding starts because people treat the whole symbol as a single blob. It isn’t. It’s a small diagram with distinct parts, and each part does one job.

Let’s clear up a naming trap first, because even seasoned hands mix these up. According to AWS A2.4, Standard Symbols for Welding, Brazing, and Nondestructive Examination, a weld symbol is just the shape that tells you the weld type — a triangle for a fillet, a V for a groove, a line for a square groove. A welding symbol is the complete graphic that may combine the arrow, reference line, tail, dimensions, and finishing details. The weld symbol is a piece of the welding symbol, not the other way around.

The Two Required Elements: Arrow and Reference Line

Every welding symbol needs exactly two things: the reference line and the arrow. Everything else is optional and added only when information is needed. Miss either required element and the print is defective.

• Reference line: A horizontal line that acts as the spine of the symbol. Weld symbols, sizes, lengths, and notes all attach to it.
• Arrow: A leader line that touches one side of the joint and connects back to the reference line (often with a bend). The end that touches the joint is the “arrow side” — the whole reason this convention exists.

Here’s a rule techs learn in training and inspectors check constantly: the weld symbol must be drawn in contact with the reference line and within its length — never dangling off either end. The position of that symbol above or below the line is what encodes arrow side versus other side, which is why the reference line is drawn long enough to hold what it needs.

The Tail: Where the Specs Live

The tail sits at the far end of the reference line, opposite the arrow, and carries reference information — the welding process (such as GMAW or SAW), a specification number, a procedure, or a note pointing to a welding procedure specification (WPS). You’ll see codes like “GTAW” or “E7018” parked there, or a reference to a spec that governs the job. When you’re setting a machine for a job with a tail calling out a process, matching your setup to the right polarity for TIG or stick work becomes part of reading the symbol correctly, not a separate task.

In the ANSI/AWS A2.4 standard, the tail is drawn as a fork shape when a process or spec is called out, and often left out entirely when it isn’t. That omission is deliberate, not sloppy drafting.

A Symbol Is a Package, Not a Single Weld

The biggest mental shift is realizing a welding symbol can specify far more than weld type. In one compact graphic you might get the joint geometry, the weld size, the length and pitch of intermittent welds, the finish, and the process — all anchored to that one reference line. This is why learning to read the arrow and reference line as a system pays off across every joint you touch, from thin sheet to heavy plate. Solid welding practice begins with reading the symbol before you strike an arc, because the drawing tells you where the deposit belongs — and the arrow is what points you to the answer.

Note: When a symbol feels cluttered, break it into layers: required elements first, then dimensions, then tail data. Read top to bottom, element by element, and the arrow-side question becomes obvious.

Arrow Side vs Other Side: Reading the Position of the Symbol

Here is the rule that untangles almost every confusing print: in the AWS single-reference-line system, a weld symbol placed on the same side of the reference line as the arrow means the weld goes on the arrow side. Move that same symbol to the opposite side of the reference line, and it becomes an other-side weld. The position of the symbol — not the arrowhead alone — tells you which face gets the weld. Read that sentence twice; it governs fillets, grooves, and every other symbol on the sheet.

That is why the layout matters. Information placed on the bottom of the reference line is tied to the side of the joint facing the arrow, while information on top refers to the other side. A symbol below the line describes a weld on the near face — the one the leader touches. The same symbol lifted above the line describes a weld on the far face, the side you would otherwise have to reach around and weld blind. Same shape, same size, opposite location.

The Rule in One Line

Welding symbols read like a sentence: the arrow points at the joint, the reference line carries the instruction, and the symbol’s side of that line carries the location. Miller’s weld-symbol guide keeps it simple — the side the arrow touches is the arrow side, and the opposite face is the other side. Internalize that, and flipping a symbol up or down instantly changes the instruction without changing anything else about the weld. This is the quiet power of the convention: one flip, two completely different jobs. Whether you are guiding a wire welder on thin sheet or running a stick rig on heavy plate, the location rule never changes.

Reading a T-Joint

Picture a T-joint with the arrow pointing at the left face of the stem. With one fillet symbol below the reference line, you weld the arrow side — the left face. If the designer wants the weld on the right face instead, the symbol flips to sit above the reference line. Nothing else changes. One line position, two entirely different fabrications, and the print never has to say “left” or “right.”

Reading a Lap Joint and Butt Joint

A lap joint behaves the same way. The arrow touches one plate, and the symbol’s side picks the overlapping face the weld lands on. On a butt joint, arrow side means the arrow-side face, while other side means the back side — common on a back-gouged root or a reinforcing back weld. Because these conventions are identical across processes, a welder running TIG or gasless MIG reads the same symbol the same way. Solid fit-up habits, the kind covered in our guide to welding practice, begin with knowing exactly which face you are welding. The symbol, not the process, defines the location.

When the Symbol Appears on Both Sides

When a weld symbol appears on both faces of the reference line — above and below — the callout means a weld on both sides of the joint. Two fillet symbols, one on each side, signal a double-fillet T-joint. A groove symbol shown top and bottom can mean a double-groove weld. This is not the same as a single symbol with a tail note; the duplication itself carries the meaning, and it is deliberate. Read double-sided callouts slowly, because a missed second symbol means a second pass you never planned for.

This convention is not limited to fillets. It applies equally to fillet, groove, plug, slot, stud, and other weld types. AWS A2.4 charts each one with location significance tables that spell out arrow side, other side, and both sides for every basic weld symbol, so you can confirm the exact face before you strike an arc.

Short Note: A symbol split across both sides is doing deliberate work. Treat it as a both-sides instruction, never as a printing error.

Joint by Joint: How Arrow Side Changes With T, Lap, Butt, and Corner Joints

The arrow side rule never changes joint to joint: it is always the member or face the arrow touches. What changes is how many faces are in play and how easy it is to point at the wrong one. AWS A2.4 defines five basic joint types — butt, corner, T, lap, and edge — and each handles the arrow a little differently. The joint type sets the stage for where errors creep in, so build symbol fluency with a structured welding practice plan before trusting your eye at the bench.

Butt Joints

A butt joint sets two plates edge to edge in one plane. With a square groove, arrow side and other side are the two faces of a single weld, so a full-penetration pass looks identical either way. Trouble starts with a bevel or V-groove. In common drafting practice, the arrow side is the side carrying the groove preparation, and the break-in-arrow convention reinforces it when both sides are prepped. Flip the arrow to the back face while the groove is cut on the front, and a fitter can prep and weld the wrong side — an expensive slip on thick plate run with high-deposition processes like robotic submerged arc welding.

Corner Joints

A corner joint closes two plates at roughly 90 degrees, forming an L. The arrow can land on either member and on either the inside or outside face. Whichever face the arrow touches becomes the arrow side; the opposite face of that same member is the other side. Move the arrow from the vertical leg to the horizontal leg and you swap the reference entirely. Single-sided corner welds are common, so this is not academic — point at the wrong member and you may weld an inaccessible inside corner while the specified outside bead is never laid. Confirm orientation before tacking, especially on thin material.

T-Joints

On a T-joint the arrow side is usually the stem plate face nearest the arrow; the other side is the opposite face of that member. The stem is the upstanding plate; the base is the flange it sits on. If the arrow touches the stem, the arrow side is that stem face, and the other side is the reverse of the stem — not the base plate. Slide the arrow onto the base plate and the reference changes completely. Because both sides of a T route loads differently, misreading this is a common fabrication error — the kind of mix-up covered when learning to tell good welds from bad. Mark the stem face with soapstone once you have confirmed it.

Lap Joints

On a lap joint the arrow can point to either the top or the bottom plate, and that choice changes the arrow-side face. Point at the top plate and the arrow side is that face; point at the bottom plate and the reference flips to the lower member. The symbol then sits on the correct side of the reference line. Get it backwards and you may weld a face that only needs a seal, double your passes, or leave the structural lap unwelded. Overlap defects and missed toes cluster here, so check the arrow before the first tack.

Edge Joints

An edge joint brings two parallel edges together and welds along the joint line. The arrow side is simply the face the arrow touches — usually the near edge face. Edge joints lean heavily on the arrow because there is often no room to reach the far side, so a flipped arrow can mean a weld that cannot physically be made. When in doubt, sketch the joint on the bench. Get it right and the prep matches the print the first time.

Arrow Side for Groove Welds, Fillet Welds, and Combination Symbols

Not every weld symbol behaves the same way when you slide it above or below the reference line. Groove welds, fillet welds, and combinations of the two each follow their own rules for how sizes, angles, and dimensions travel with the symbol — and with its side. Get this right and the print reads cleanly. Get it wrong and you’ll be grinding out a weld that was never supposed to be there.

Groove Welds and Their Dimensions

Groove weld symbols include square, V, bevel, U, J, flare-V, and flare-bevel. Each can sit on the arrow side or the other side of the reference line, and the letter or shape tells you the joint preparation, not the location. Location is decided purely by which side of the line the symbol rests on.

Here’s the part that trips people up: the dimensions attached to a groove symbol belong to that symbol and that side. Groove angle, root opening, depth of bevel, and groove weld size are tied to the specific weld you’re calling out. So a 60° included angle with a 1/8 in. root opening above the line describes the groove on that reference-line side — not a mirrored groove on the opposite face.

• Groove angle: total included angle of the preparation, placed above or below the symbol shape.
• Root opening: the gap at the root, shown inside the symbol.
• Depth of bevel: how deep the bevel cuts, shown to the left of the symbol.
• Groove weld size: the required throat or size, keyed to the symbol.

The AWS A2.4 standard lays out exactly where each goes, and the logic is consistent: every dimension lives on the same side of the reference line as its weld symbol. For a deeper look at how preparation and technique interact once the arc strikes, our guide to building real welding skills is worth a read.

Fillet Welds: Size, Length, and Pitch

Fillet symbols follow the same side logic but carry a distinct set of dimensions. Fillet weld size, length, and pitch sit to the left of the fillet symbol — and critically, on the same side of the reference line as that weld. A fillet on the arrow side shows its size and length above the line; one on the other side shows them below.

Pitch only appears for intermittent welds. The format reads length–pitch, so 3–9 means a 3 in. weld followed by 9 in. center-to-center spacing. That number governs the whole run, so flipping its side lays beads on the wrong face with the wrong rhythm. It’s why telling good from bad welds starts with reading the callout, not the bead.

Combination Symbols: Stacking Without Confusion

A combination weld symbol stacks two or more weld symbols on the same side of the reference line to specify multiple welds — a fillet with a groove, or two grooves together. The stacking is vertical because both welds sit on that same face.

When symbols stack, each weld keeps its own dimensions. Read top to bottom and match each dimension set to the symbol it touches, not to the stack as a whole. The most common mix-up is grabbing the angle from the groove and applying it to the fillet size beside it.

When the same weld is required on both faces of a joint, that’s the “both sides” condition: place the appropriate symbol on both sides of the reference line. A fillet above and the same fillet below means weld both sides.

Note: The official symbol chart and the AWS A2.4 standard are the authority here — when a stack looks ambiguous, consult the chart rather than guessing. Before you strike an arc, make sure your gear is dialed in; our GMAW contact tip guide is a solid starting point for keeping the gun consistent.

Master these three families — groove, fillet, and combination — and every remaining symbol becomes a variation on a theme you already understand.

The Break in the Arrow: A Special Case You Must Not Ignore

When you read a welding symbol, the arrow is usually a straight line pointing to the joint. Sometimes, though, that arrow has a sharp bend or kink at its very end. This small detail—the “break in the arrow” or “broken arrow”—is one of the most important clarifiers on a print. That single bend can be the difference between a passing weld and an expensive rework. For asymmetric joints, the kink tells you which side needs joint preparation or beveling, preventing the costly mistake of prepping the wrong face.

Why the Break Exists

Not every joint is mirrored. Take a single-bevel groove weld: only one plate is beveled, the other stays square. A straight arrow with a bevel symbol would leave it unclear which member to prepare. To remove that ambiguity, AWS A2.4: Standard Symbols for Welding, Brazing, and Nondestructive Examination includes a dedicated section on the break in the arrow. The kink directs the arrow side to the member that must be beveled, leaving no guesswork for the welder on the shop floor.

This matters most on precision cuts. For shops working with weld tube fittings or structural fabrications, a misread bevel throws off the entire fit-up. Spotting the break can save hours of rework and prevent inspection failures.

Reading the Broken Arrow in Practice

When you see a kink, follow the arrow to the joint; the “arrow side” is the side the bent end points to. For a single-bevel symbol, the groove prep goes on that arrow-side member. Same rule for a single-J groove. These sketch-style break symbols are a staple on modern prints, and they are reflected in international standards too, with ISO 2553 outlining its own approach to arrow-side clarity.

The broken-arrow convention also works alongside your broader skill set. Machine settings—such as polarity for flux core welding or TIG welding polarity—matter just as much as reading the print. An accurate symbol falls flat if your parameters are off, which is why consistent welding practice is crucial.

Modifiers That Work Alongside the Arrow

While the break clarifies location, supplementary symbols modify how a weld is applied without changing which side the arrow points to. Two of the most common are:

• Weld-all-around: a small circle at the junction of the reference line and the arrow, meaning the weld runs around the entire joint, such as the perimeter of a pipe or a round boss.
• Field weld: a flag at that same junction, showing the weld is to be performed in the field, not the shop.

These modifiers are standard across AWS weld symbol charts, and they often appear on the same prints as broken arrows. On large projects like robotic submerged arc welding, they help coordinate shop and field work precisely.

Final Takeaways for the Shop Floor

Before striking an arc on an asymmetric joint, run a quick checklist: scan for a kink at the arrow end, confirm the arrow-side member, check for a weld-all-around circle or field weld flag, and verify your joint prep matches the symbol. Those seconds protect your time, materials, and pass rate—and inspection failures from a misread symbol are entirely avoidable.

The break in the arrow is not decorative. It is a deliberate safety and accuracy tool written by the designer for you. Respect it, and you will spend far less time fixing mistakes and far more time laying down clean, code-compliant welds.

AWS A2.4 vs ISO 2553: Two Different Arrow-Side Systems

Welding symbols are not a universal language. A drawing prepared to the American system and one prepared to the international system can look almost identical, yet the arrow side can mean something entirely different. For shops that cross borders — or work with vendors using different standards — knowing this distinction can prevent costly errors.

The two key standards are AWS A2.4 and ISO 2553. Each answers the arrow-side question differently, and mixing them is a genuine fabrication hazard.

The AWS A2.4 Approach: One Reference Line

AWS A2.4 uses a single reference line. Every weld symbol sits either above or below that line. A symbol below the line means the weld goes on the arrow side; a symbol above the line means the other side. No second line or dash pattern needs to be decoded.

This simplicity is its strength. For fabricators working entirely in the US, it is fast to read and easy to apply. AWS A2.4:2020 also added an informative annex on ISO 2553 welding symbols, allowing users to cross-reference the two systems without leaving the standard.

The ISO 2553 Approach: System A and System B

ISO 2553:2019 recognizes two approaches already in wide use for designating the arrow side and other side. Rather than picking a winner, it documents both and labels them with suffixes:

• Clauses, tables, and figures with the suffix “A” apply to the dual-reference-line system.
• Clauses, tables, and figures with the suffix “B” apply to the single-reference-line system.

System B will feel familiar to anyone who has read AWS drawings, as it uses a single reference line in much the same way. System A is the one most likely to cause confusion.

Inside the Dual-Reference-Line System

In System A, the symbol uses two reference lines stacked together:

• A solid line carries the weld that goes on the arrow side.
• A dashed line carries the weld that goes on the other side.

In this system, the arrow side is not determined by position above or below a single line — it is determined by which line the symbol sits on. A symbol on the solid line is an arrow-side weld, while a symbol on the dashed line is an other-side weld. Miss the dash, and you will flip the joint.

One Standard, More Than Welding

ISO 2553 does not stop at arc welding. Its principles also apply to soldered and brazed joints. For those prints, the same solid and dashed conventions apply, so an arrow-side error can be just as costly — a brazed assembly with filler applied to the wrong face may be scrapped outright.

The Danger of Mixing the Two Systems

This is where real losses occur. Picture a shop running both American and European work. A welder reads a System A symbol the AWS way — treating the dashed line as a second position marker — and puts the weld on the reverse face. On a lap joint, that can bury the weld where it adds no strength. On a double-sided groove weld, an entire pass may need to be gouged out.

The fix is procedural:

1. Check the title block and drawing notes for the controlling standard (AWS A2.4 or ISO 2553, and which system).
2. Never assume a symbol’s meaning based on “how we usually do it.”
3. Standardize within a single project — do not blend symbols from two systems on one print.
4. Train new hands on both systems, especially if you take on international contracts.

When a drawing is ambiguous, ask before you strike an arc. A two-minute conversation with the detailer beats a two-hour repair. The same discipline that keeps good and bad welds apart at the bench keeps your symbol reading straight — read the print, confirm the standard, then weld.

For related symbol and setup fundamentals, it also pays to revisit your broader welding practice habits. Knowing ISO 2553 and AWS A2.4 cold means you can walk onto any job, read the arrow side correctly, and never gamble on which face gets the weld.

Common Arrow Side Mistakes (and How to Avoid Them)

Nobody sets out to weld the wrong face of a joint, yet it happens weekly on shop floors. A weld on the wrong side often gets gouged out and redone, and the extra heat can pull thin parts into distortion. Worse, an inspection failure on a critical joint can stop an entire fabrication. Here are the mistakes that cause most of that pain — and the habits that prevent them.

Mistake 1: Reading the Drawing View Instead of the Joint

The leading cause of arrow-side errors is treating the drawing view as the basis of reference. It is not. In AWS A2.4, the joint is the reference. The arrow side is the side of the joint the arrow touches. A symbol above the reference line means the weld sits on the arrow side.

Corrective habit: Before you strike an arc, trace your gloved finger from the arrow tip to the joint and name the face it touches: “This side.” Do it on every fit-up.

Mistake 2: Missing the “Both Sides” Condition

A symbol with weld data on both sides of the reference line means weld on both sides of the joint. Miss that and you run a single-sided fillet where the engineer called for a balanced, double-sided weld — leaving the joint under-strength and prone to fatigue cracking. It’s a classic cause of rework.

Corrective habit: Always check the far side of the reference line before you set up. If there’s a dimension or symbol there, you have two welds to plan, not one.

Mistake 3: Assuming “Arrow Side” Means “Near Side”

The arrow usually points at the near side of the view — but not always. On complex views, hidden details and section cuts can put the arrow on the far face. The Miller weld symbol guide stresses that the arrow side is defined by the joint and the arrow’s contact point, not by what’s closest to your eyes. Welders who assume near side often tack the wrong face.

Corrective habit: Read the arrow as “this face of the joint,” not “the face I can see.” When in doubt, walk around to the physical part and orient yourself.

Mistake 4: Misreading the Symbol After Flipping a Part

Because the joint is the reference, flipping or re-orienting a part does not change which side is the arrow side — no matter how you rotate the assembly. Confusion arises when welders re-read the symbol from the new orientation and swap the sides.

Corrective habit: Mark the arrow side on the part with a soapstone X during fit-up, before the part gets flipped. Then the symbol can’t be re-interpreted mid-job.

Mistake 5: Ignoring the Break in the Arrow

A broken arrow — one with a zigzag or offset — signals that the weld goes on the side opposite where the arrow points. Ignoring it can place groove preparation on the wrong side of a one-sided joint, where rework is most expensive. Treat the break as a warning sign.

Corrective habit: Any time you see a break in the arrow, stop and confirm the intended side with the engineer or fit-up drawing before burning metal.

Mistake 6: Mixing AWS and ISO Conventions

Mixing AWS A2.4 and ISO 2553 symbol conventions on the same project is a recognized source of misinterpretation because the two systems show the other side differently — most visibly in how side information is positioned. A weld that reads one way in AWS can read the opposite in ISO. Check the title block or project spec for the governing standard.

None of these mistakes are exotic — they’re everyday slips that cost fabricators time, material, and credibility. If you’re building skills systematically, treat arrow-side reading as a core drill alongside your welding practice, because a perfect bead on the wrong face is still a failed weld.

Practical Tips: Using Arrow Side Correctly on the Shop Floor

Reading a welding symbol in a classroom is one thing; applying it on a dirty shop floor with the clock running is another. The gap between the two is where most arrow-side errors happen. These habits close that gap.

Mark the Arrow Side Before You Fit

Before two parts ever meet, grab a soapstone or paint marker and write the arrow-side convention directly onto the joint. A simple leader line or an “arrow side / other side” note removes all guessing at the bench. This one move prevents the classic lap-joint mistake: welding the face opposite the one the designer intended and doubling your work. If the part will be painted or galvanized, mark a non-critical face so your notes don’t become a finishing problem. Clean, intentional fit-up for weld tube fittings starts with knowing exactly which surface carries the weld.

Verify Against the WPS and the Drawing

Every symbol on a print should line up with a qualified welding procedure specification (WPS). Verifying the arrow side against the WPS before welding prevents applying a qualified process to the wrong joint, which is a common root cause of inspection failures. Before striking an arc, confirm the side shown matches the process, position, and pass sequence in the procedure. If the drawing calls for a groove weld on the arrow side but the WPS was qualified for a fillet, that mismatch is a red flag — stop and ask. When in doubt, ask the designer or inspector rather than guess.

Read the Tail for Process and Specification

The tail of the symbol isn’t decoration. It can reference the process, a specification, or other instructions that must match the side shown. If the tail reads “GTAW” or points to a spec number, treat it as a checkbox: does my qualified procedure cover this? For precision work, matching polarity and process to the symbol matters as much as the geometry — the same discipline covered in TIG welding polarity.

Keep an Up-to-Date Symbol Chart at the Bench

Post an up-to-date AWS A2.4 welding symbol chart where welders and fitters can actually see it. Symbols evolve — the 2020 edition of AWS A2.4 introduced changes that still trip up crews relying on older references. A laminated chart beats a phone screen when your gloves are on, and it keeps interpretation fast and consistent across every shift.

Do a Pre-Weld Visual Check

A pre-weld fit-up check that confirms arrow-side and other-side weld locations can catch errors before material is committed. Walk the joint: measure root gaps, verify tack placement, and confirm the weld is landing on the correct face — the same sharp eye you use for telling good and bad MIG welds apart. Then photograph the staged joint for the inspection record so quality control can confirm intent later. It is far cheaper than repair, and it builds the paper trail inspectors trust.

Talk to Each Other

Consistent symbol interpretation between designer, fitter, and welder is essential to weld quality and dimensional accuracy. The designer knows intent, the fitter controls orientation, and the welder controls the arc. When any one assumes and the others don’t verify, the arrow side gets flipped. A two-minute huddle over an unfamiliar symbol beats an afternoon of rework — and it is exactly the kind of deliberate welding practice that turns reading skill into real capability.

None of this works if the symbol stays on the paper. Mark the part, check the tail, keep the chart handy, and verify before you strike an arc. That routine connects what the drawing says to what you actually weld — and it is what separates a crew that passes inspection from one that reworks the same joint twice. Read it, mark it, weld it — in that order.

Conclusion: Mastering Arrow Side for Cleaner, Faster Fabrication

Getting the arrow side right is one of the smallest habits in fabrication — and one of the most profitable. A correctly read symbol puts the weld on the right face the first time, which cuts rework, saves filler and grinding time, and keeps parts flowing through inspection instead of circling back to the bench. Weld the wrong face of a lap joint and you add heat, distortion, cleanup, and the risk of an overlap defect. Multiply that across a shift and the savings are obvious.

Safety rides on the same habit. Welding the wrong side can mean an under-sized weld in a critical joint, extra grinding in awkward positions, or a repaired member that’s been heated twice — all of which raise the odds of a defect slipping through. Reading the symbol correctly keeps the work where the engineer intended it and keeps you out of unnecessary rework.

Strip away the drawing clutter and there are only three location conditions to remember: arrow side, other side, and both sides. That’s it. Whether the symbol sits above or below the reference line, and whether it’s a fillet, groove, or combination weld, the drawing is only telling you which of those three applies. The arrow side is always the side of the joint the arrow points to — regardless of how the drawing is oriented on the page or how the part sits on your table. Train your eye to check that pointer first, and the rest of the symbol falls into place.

And never overlook the break in the arrow. It’s the one case where the symbol deliberately changes the location condition, flipping the intended side of the joint. Miss it and you can weld the wrong member entirely. The same discipline applies to a symbol whose tail carries a process note — read every part, not just the arrow.

Deliberate practice is what turns this knowledge into speed. The fabricators who read symbols without thinking didn’t memorize a thousand charts; they ran the same check hundreds of times until it became reflex. If you want to build that kind of fluency with your hands and your eye at the same time, our guide to welding practice is a good next step. Pair it with clean, consistent results — the sort we break down in good and bad MIG welds — and you’ll spot a misread before it becomes scrap. If you want a second reference beside your bench, Miller’s guide to how to read and understand weld symbols is a solid companion.

Your Five-Second Symbol Routine

Run the same quick sequence on every symbol:

1. Find the arrow and note which member it touches — that’s the arrow side.
2. Check whether the symbol sits above or below the reference line.
3. Confirm the standard (AWS A2.4 or ISO 2553).
4. Watch for a break in the arrow.
5. Read size, length, pitch, and any tail notes before you weld.

Set that routine in a well-planned bay — if you’re still organizing your space, see our guide to welding facilities — and it becomes near-automatic.

None of this requires genius. It requires slowing down for five seconds, trusting the convention, and letting repetition do the rest. Get the arrow side right and you get first-time quality, lower cost, and a safer, calmer shop. That’s the whole payoff, and it starts with one little arrow.

Below, we answer the questions fabricators ask most about arrow side welding.

Frequently Asked Questions

What does arrow side mean in welding?

The arrow side is the side of the joint that the arrow of the welding symbol points to. In the AWS system, a weld symbol placed on the arrow side of the reference line means the weld goes on that face, while a symbol on the other side of the line means the weld goes on the opposite face.

How do I tell the arrow side from the other side?

Look at which side of the joint the arrow touches — that is the arrow side. The opposite face is the other side. In AWS drawings, the position of the weld symbol (same side as the arrow versus opposite) tells you which face gets the weld.

What is the difference between arrow side and other side welding symbols?

A weld symbol shown on the same side of the reference line as the arrow specifies a weld on the arrow side. A weld symbol shown on the opposite side of the reference line specifies a weld on the other side, and symbols on both sides mean welds on both faces.

How does ISO 2553 show the arrow side and other side?

ISO 2553 uses two recognized systems. In the dual-reference-line system, a solid line represents the arrow side and a dashed line represents the other side. In the single-reference-line system, position relative to the line is used, similar to AWS.

What is the break in the arrow used for?

A break (bend) in the arrow tells you that a specific side — often the side requiring joint preparation or beveling — must be the arrow side. It removes ambiguity on asymmetric joints where the weld or preparation can only be made from one face.

Does ‘arrow side’ mean the near side of the drawing view?

No. The joint is the basis of reference, not the drawing view. The arrow side depends only on which side of the joint the arrow points to, so the same joint keeps its arrow side even if the part is flipped or the drawing view changes.

Can a weld be required on both sides of a joint?

Yes. When a weld symbol is placed on both sides of the reference line, or both a solid and dashed line are used in ISO, it indicates welding on both sides of the joint. This is one of the three location conditions defined in AWS A2.4.

Why is misreading the arrow side a common mistake?

It usually happens when someone reads the drawing view instead of the joint, ignores the break in the arrow, or mixes AWS and ISO conventions. The result is welding the wrong face, missing a double-sided weld, or failing inspection and requiring rework.

Authoritative Sources & Further Reading

• https://pubs.aws.org/Download_PDFS/2__A2_4_2020_PV.pdf
• https://pubs.aws.org/Download_PDFS/A2.4_2007PV.pdf
• https://app.aws.org/mwf/attachments/64/225364/AWSWeldSymbolchart.pdf
• https://blog.ansi.org/ansi/standard-welding-symbol-change-aws-a2-4-2020
• https://webstore.ansi.org/standards/aws/awsa22007
• https://www.iso.org/standard/72740.html
• https://committee.iso.org/cms/live/live/en/sites/isoorg/contents/data/standard/04/21/42192.html
• https://www.millerwelds.com/en-US/resources/knowledge-hub/welding-basics/how-to-read-and-understand-weld-symbols
• https://www.osha.gov/welding-cutting-brazing
• https://www.cdc.gov/niosh/topics/welding/default.html