Why would a quote for custom tube bending services change between the first number and the final invoice? Every follow-up asking about material grade, wall thickness, or surface finish is a round-trip the job doesn’t need. Shops quote what they’re given, and a quote will reflect incomplete specifications.
Getting a firm quote that holds through fabrication and delivery starts with the request for quote (RFQ). The five steps below cover what Atlas needs to price a job accurately and move it into production without the back-and-forth.
Step 1: Specify Your Material Completely
Material is the first variable that determines whether a job can be run, what tooling it requires, and what it costs. A specification that simply reads “Steel tube, 1″ OD” leaves out information driving those decisions.
Outside diameter and wall thickness
State both in consistent units using either inches or metric. Wall thickness isn’t interchangeable with schedule pipe designations unless the conversion has been confirmed.
Material grade and alloy
A513 carbon steel, 304 stainless, and 6061 aluminum bend, price, and tool differently. Grade and alloy belong on the RFQ.
Seamless or welded construction
For thin-wall bending, seam orientation affects where distortion risk is highest through the bend. A shop that doesn’t know the construction can’t account for it in the setup.
Tube sizing versus pipe sizing
Tube is sized by outside diameter and wall thickness. Pipe is sized by nominal pipe size (NPS) and schedule, where the NPS designation doesn’t correspond to the outside diameter (OD). Confusing the two is one of the most common specification errors and it produces parts made to the wrong dimensions. If the order is for pipe, state the NPS and schedule. If it’s for tube, state the OD and wall.
Step 2: Define the Bend Geometry
Geometry errors in a bending RFQ are the result of missing information or unclear dimensions. Include the required centerline radius, finished bend angles, straight lengths, and rotational orientation between bends so the part can be quoted accurately and produced to fit the assembly.
Centerline radius (CLR)
All bend radii in tube and pipe bending are measured to the centerline of the tube. A drawing specifying an inner or outer radius without identifying it as such will be interpreted as CLR and produce a part with the wrong geometry. State the CLR explicitly.
Straight sections
CNC rotary draw bending requires a minimum straight or tangent length before the first bend and after the last for the clamping and pressure dies to engage cleanly. A drawing placing a bend too close to the end of the tube requires a design modification before it can be quoted. Include straight lengths at each end and between bends.
Multi-plane orientation
For parts with bends in more than one plane, the rotational angle between bends must be specified. A verbal description isn’t sufficient. Send a 3D drawing or a STEP file. Parts that are dimensionally correct in isolation but won’t assemble in three dimensions are a drawing problem.
Step 3: Understand How Tolerances Affect Feasibility and Price
Tolerances tighter than the process can reliably hold add inspection time, scrap risk, and cost without adding value to the application. Tolerances left unspecified become the shop’s default, which may not match what the application requires.
Bend angle tolerance
CNC rotary draw bending holds ±1° under standard production conditions. Requirements tighter than ±1° narrow the field of viable methods and add cost. If the application genuinely requires it, state the tolerance and be prepared to discuss the justification.
Centerline radius tolerance
Centerline radius is determined by the fixed radius of the bending tooling, while the finished radius can vary with material, wall thickness, and springback. Customers should specify the CLR tolerance their assembly requires, particularly when tighter fit-up or dimensional control is critical.
Ovality
Bending compresses the cross-section of the tube at the bend. For applications governed by ASME B31.1 or B31.3, the allowable ovality limit is 8 percent of the nominal outside diameter. Applications outside those standards should specify what the application can tolerate, particularly for flow-critical or pressure-critical service.
Wall thinning
The outer wall of a bend thins as material stretches through the radius. Thinning is predictable and calculable, and mandrel support limits it significantly. For pressure-critical applications, specify the minimum wall thickness required after bending. A shop that knows the limit can confirm compliance before the job runs.
If tolerances are drawn from a recognized standard such as ASME B31.3 or CSA Z662, state the standard on the RFQ instead of restating every callout individually. Atlas confirms tolerance compliance as part of the drawing review process.
Step 4: State Quantity, Run Type, and Anticipated Future Volume
Quantity affects tooling decisions, scheduling, per-unit pricing, and which process is right for the job. A one-off quoted without knowledge of the anticipated production volume may be set up with tooling that doesn’t scale, at a per-unit cost that doesn’t reflect the economics of production volume.
Current order quantity
State the exact quantity for the current order.
Run type
Distinguish between a one-off, a short run, and a production run. The economics of tooling investment are different for each. If we’re aware a job is likely to repeat, we can make tooling decisions at the prototype stage that pay off at volume.
Anticipated future volume
Note any future project volume at the quoting stage. When we know volume is coming, we can design the setup for repeatability rather than just the immediate run. Discovering anticipated volume after the first order is placed requires retooling.
Lead time
State the required delivery date clearly. Rush timelines carry a cost, and an honest lead time is more useful than an optimistic one. Atlas quotes a schedule it can stand behind before anything is committed to.
Step 5: Include Finishing, Documentation, and Delivery Requirements
Galvanizing, coating, and passivation interact with the formed part in ways that need to be planned before the first bend is made. Documentation requirements not disclosed at quoting, including material test reports (MTRs), inspection records, and weld certifications, require certified material stock, additional inspection steps, and records that can’t be produced retroactively.
Finishing
State if bare, hot-dip galvanized, painted, powder coated, or passivated surface conditions are required. Atlas coordinates hot-dip galvanizing through established Saskatchewan partners, so components arrive site-ready without an additional step in the supply chain. Finishing requirements affect material selection, handling, and sequencing, and should be part of the RFQ.
Documentation
Spec-driven projects carry documentation requirements that can’t be worked backwards from a finished part. Certified material for MTR traceability needs to be sourced in advance. Inspection records, weld certifications under CWB certified processes, and customer-specified quality controls need to be scoped into the job from the quoting stage. Atlas carries ISO 9001:2015 certification, and documentation requirements are scoped into every job that specifies them.
Delivery
Include the delivery address, deadline date, preferred freight method, and any site or packaging requirements. Atlas arranges transport as part of the job and ships nationally from Saskatoon. Delivery requirements confirmed at the quoting stage are built into the schedule.
Send Atlas What You Have
Projects don’t always arrive with complete specifications. Drawings are still in progress, tolerances are waiting on confirmation from the customer, or the material hasn’t been fully called out yet. Reaching out before everything is finalized is a better approach.
Atlas’s quoting process starts with a drawing review. Questions surfacing at that stage are considerably easier to work through than the same questions raised after fabrication has started. Where drawings don’t exist yet, a sample part or a dimensioned sketch is enough to open the conversation.
Forward your drawings and specs to the Atlas team, and we’ll clarify everything before a number goes out. Start your quote.
Frequently Asked Questions: Getting a Quote for Custom Tube Bending Services
What file formats does Atlas accept for bending drawings?
STEP files are the preferred format for multi-plane or complex bending work because they capture 3D geometry and rotational orientation accurately. 2D DXF and PDF drawings work for single-plane jobs where all geometry can be fully defined in two dimensions. For jobs without formal drawings, a dimensioned sketch or a sample part is enough to open the quoting conversation.
Can Atlas quote a job where the specification isn’t fully worked out yet?
Yes. Atlas’s quoting process starts with a drawing review, and that review can highlight any specification gaps before they become fabrication problems. A partial specification or a work-in-progress drawing is a reasonable starting point. Where significant details are still undecided, Atlas can provide a preliminary range and firm the quote once the specification is complete.
What happens if the tolerances on my drawing are tighter than the process can hold?
Atlas reviews tolerances as part of the quoting process and will flag requirements exceeding what CNC rotary draw bending can reliably deliver. In some cases, the application can tolerate a slightly relaxed tolerance without affecting function, and a conversation about the end use resolves it. Where the tolerance genuinely needs to hold, Atlas will advise on what achieving it requires and price accordingly.
Are material test reports (MTRs) included as standard on every job?
MTRs are available on request and are standard on jobs where they are specified at quoting. For jobs where material traceability isn’t required, Atlas sources material through established supply channels without the additional cost of certified stock. Whether certified material is needed has to be established before the order is placed, not after fabrication is complete.
What is the minimum straight length required before and after a bend?
The minimum depends on the tube or pipe size and the tooling configuration. Atlas typically needs enough straight length for the clamping die to engage cleanly, often around three times the outside diameter of the tube. Very short tangent lengths or bends placed close together may require compound or modified tooling, which can add setup time and tooling cost. Flag these conditions at the RFQ stage so the geometry can be reviewed before quoting.