Cut to Length Tolerance Sawing: What Deviations Are Normal in a Saw Cut

A cut is ordered, but the length deviates slightly. Is that already a defect or still normal?

Cut to length tolerance sawing gives a clear answer. Vulcanus has manufactured precisely since 1984 and knows these limits from practice.

This article explains typical values, standards and influencing factors. You will learn how to specify your sawn cut correctly.

Key Takeaways

• In sawing, dimensional deviations are technically normal and unavoidable.
• Typical length tolerances are about ± 0.5 to ± 2 mm, depending on saw, length and cross-section.
• The usual basis is the general tolerance to DIN ISO 2768-1, often class m or c.
• Besides length, squareness and angle matter, for example in mitre cuts.
• Cross-section dimensions come from the stock material. The saw only determines length, angle and cut face.
• Tighter tolerances are possible, but cost more time and money.

What Is Sawing and Which Tolerances Apply?

In sawing, material is separated with a saw blade. The process is fast, economical and widely used. For straight cuts, it is usually the first choice.

No cutting process, however, works perfectly exact. Every sawn dimension moves within a certain range.

Exactly this range is the tolerance. It defines which deviation is still permissible. Within this limit, the part counts as correct.

Typical Cut to Length Tolerances at a Glance

The achievable accuracy depends on process and part. The following values serve as practical orientation.

Common Length Tolerances

For pure sawing, moderate deviations are normal. They usually lie in the millimetre range.

• Standard production saw cut: often about ± 0.5 to ± 2.0 mm
• Panel saw, thicker aluminium plates: sometimes down to about ± 0.3 mm
• Stockist cut bar stock up to 500 mm: often about + 5 / − 0 mm
• Stockist cut bar stock over 500 mm: often about + 10 / − 10 mm

The coarse bar stock values come from metal stockists. They describe delivery lengths, not machining dimensions. Binding is always the specific agreement in the order.

Saw Cut Tolerances by Sawing Method

The type of saw clearly affects length, angle and cut face. The values are guide values for well-maintained machines:

Sawing method	Typical length tolerance	Squareness of the cut face	Kerf	Typical use
Band saw with stop or feed	± 0.5 to ± 1.0 mm	about 0.2 to 0.5 mm per 100 mm cut height	about 1 to 2 mm	Round bar, sections, large cross-sections
Cold circular saw	± 0.1 to ± 0.3 mm	about 0.1 mm per 100 mm cut height	about 2 to 4 mm	Tubes, sections, smaller solids in series
Panel saw	± 0.1 to ± 0.3 mm	very good, guided cut	about 3 to 5 mm	Aluminium and plastic plates
Stockist cut	± 1 to ± 2 mm or + 5 / − 0 mm	not specified	depends on saw	Raw material for further machining

The kerf is not a tolerance value. It matters, however, when many parts are cut from one bar. Our guide to metal sawing methods gives an overview of the processes.

Why There Is No Single Standard Value

One value for all cases would be misleading. Material, length and cross-section change the result clearly.

So serious suppliers state ranges instead of a fixed value. Critical dimensions are agreed in advance. This avoids surprises later.

Tolerance Table to DIN ISO 2768-1

If the drawing gives no individual tolerance, the general tolerance usually applies. The class is stated on the drawing, for example “ISO 2768-m”.

Linear Dimensions

Nominal size in mm	f (fine)	m (medium)	c (coarse)	v (very coarse)
0.5 to 3	± 0.05	± 0.1	± 0.2	n/a
over 3 to 6	± 0.05	± 0.1	± 0.3	± 0.5
over 6 to 30	± 0.1	± 0.2	± 0.5	± 1.0
over 30 to 120	± 0.15	± 0.3	± 0.8	± 1.5
over 120 to 400	± 0.2	± 0.5	± 1.2	± 2.5
over 400 to 1000	± 0.3	± 0.8	± 2.0	± 4.0
over 1000 to 2000	± 0.5	± 1.2	± 3.0	± 6.0
over 2000 to 4000	n/a	± 2.0	± 4.0	± 8.0

All values in millimetres. “n/a” means the standard defines no value for this range.

Angular Dimensions

The angular tolerance depends on the length of the shorter leg.

Shorter leg in mm	f and m	c	v
up to 10	± 1°	± 1° 30′	± 3°
over 10 to 50	± 0° 30′	± 1°	± 2°
over 50 to 120	± 0° 20′	± 0° 30′	± 1°
over 120 to 400	± 0° 10′	± 0° 15′	± 0° 30′
over 400	± 0° 5′	± 0° 10′	± 0° 20′

Which Class Suits a Saw Cut?

A cleanly sawn production blank usually reaches class m at medium lengths. For long parts or stockist cuts, class c is more realistic. A value of ± 2 mm corresponds exactly to class c for lengths of 400 to 1000 mm.

Read more about tolerance types in our guide to manufacturing tolerance. When a fit is needed instead of a tolerance is explained in What is a fit?

An Example: How the Tolerance Is Applied

An example makes the tolerance tangible. Suppose you order a cut of 100 x 1800 millimetres.

With a tolerance of about ±1.2 millimetres, a slight deviation is allowed. A dimension of 100.3 x 1798.8 millimetres is then within range.

So the part counts as correctly made. Only outside this range is there a real dimensional error.

Edge Quality and Burrs in Sawing

Tolerance concerns more than the length. The edge is an important quality feature too.

A clean saw cut is smooth and free of tear-out. Small burrs at the cut edge are, however, normal.

Slight tear-out in the tenths range is usually not a defect. If needed, the edge is deburred afterwards.

Squareness and Right Angles

Besides the length, the cut angle counts. Squareness describes how exactly the cut face stands perpendicular to the workpiece axis.

The deviation grows with cut height. A band saw blade can wander slightly in the material. At 200 mm cut height, 0.5 mm or more is quickly possible.

If an exactly square end face is needed, it is face milled or turned after sawing.

Mitre Cuts

For mitre cuts, an angle of ± 0.5° to ± 1° is common. For short legs, this matches class m to DIN ISO 2768-1.

On frames, small angle errors add up across all corners. For visible or welded frames, a tighter angle specification is worthwhile.

Standards for Cut to Length Tolerance Sawing

Without a specification, general tolerances usually apply. These standards create a common basis.

DIN ISO 2768-1 as the Basis

The most important standard is DIN ISO 2768-1 for length and angle dimensions. It defines tolerances in several accuracy classes.

The classes range from fine (f) through medium (m) to coarse (c). For saw cuts, the medium class is often relevant.

Further Relevant Standards

The saw determines length and angle. Cross-section, straightness and thickness, however, come from the stock material. Separate standards apply:

• EN 10060: hot-rolled steel round bars
• EN 10058: hot-rolled steel flat bars
• EN 10278: bright steel products, i.e. drawn or peeled bars
• EN 10029: hot-rolled steel plates 3 mm thick or above
• EN 485-4: aluminium sheets and plates
• EN ISO 9013: tolerances for thermal cutting such as laser, plasma and oxy-fuel

Depending on the industry, further standards apply. Internal drawing specifications can also be relevant.

Which Factors Influence the Tolerance

Dimensional accuracy is not by chance. Several factors work together on the result.

Blade and Machine Condition

The condition and type of the saw blade strongly influence the cut. A worn blade produces larger deviations.

The maintenance of the machine also plays a role. A well-adjusted saw works more consistently. Regular checks secure stable results.

Material, Length and Cross-Section

The material determines how cleanly it can be separated. Tough materials tend to make the blade wander more than mild steel. Our tips on machining stainless steel cover this in practice. Our guide to CNC machining materials compares material properties.

With increasing length and thickness, the possible deviation grows. Narrow strips can also twist during sawing. Residual stresses are released during cutting and can distort the part.

Clamping and Temperature

Secure clamping of the material is decisive. If the part slips, dimensional accuracy suffers.

Temperature also has a measurable effect. A 2000 mm steel blank grows by about 0.23 mm when it warms by 10 K. Aluminium expands twice as much and grows by about 0.46 mm. Measure only once the part has reached room temperature.

Sawing, Milling and Laser in an Accuracy Comparison

Not every process reaches the same precision. The choice depends on the required tolerance.

Process	Typical dimensional tolerance	Strength	Limit
Band saw	± 0.5 to ± 2 mm	large cross-sections, low cost	squareness on high cuts
Cold circular saw	± 0.1 to ± 0.3 mm	clean, square cuts	limited cut height
Laser cutting	± 0.1 to ± 0.2 mm	contours in sheet	more effort on thick plate
Waterjet cutting	± 0.1 to ± 0.25 mm	no heat input	slower on large thicknesses
Plasma cutting	± 0.5 to ± 1 mm	thicker sheet, fast	bevelled cut edges
CNC milling	± 0.01 to ± 0.05 mm	functional faces and fits	higher effort

For a detailed comparison, see our guide to metal cutting processes compared.

Saw Cut

Sawing is the cheapest process for straight cuts. For raw cuts, it is usually completely sufficient.

The tolerance typically lies in the millimetre range. For many applications, this is no problem.

CNC Milling for Tight Tolerances

If tighter dimensions are needed, CNC milling helps. Tolerances in the hundredths range are possible, typically ± 0.01 to ± 0.05 mm.

The effort is higher than for sawing. This precision pays off mainly on functional faces.

Laser and Waterjet Cutting

Laser and waterjet cut thinner sheets precisely. For thick solid material, they are less common.

Here too, tolerances in the tenths range are achievable. The right process depends on the component.

Raw Cut or Finished Size? The Right Strategy

Often a two-stage approach is most economical. First it is roughly sawn, then finely machined if needed.

The saw cut delivers the raw size quickly and cheaply. Then a machining step brings the tight tolerance. Both steps mesh seamlessly.

So you pay for precision only where it is needed. This noticeably lowers the cost.

Plan Allowance for Post-Machining

If a part is to be milled or turned later, it needs allowance. About 1 to 3 mm per end face is common.

So enough material remains for the finish cut. The final size arises only in the machining step. Guide values for all processes are in our guide to machining allowance.

When Tighter Tolerances Make Sense

Not every part needs tight tolerances. Often an economical saw cut is completely sufficient.

Tight tolerances make sense for mating faces and functional dimensions. There, cost and precision decide the result.

For raw cuts with later machining, the rough length suffices. The precision then arises in the next step.

Tight Tolerance Costs More

Every extra accuracy raises the effort. Inspection time, scrap risk and machining increase.

So ask only for what the function truly needs. Over-specification drives the cost up needlessly. See how CNC quotes are calculated to understand the price impact. Our guide on how to reduce per part cost adds practical levers.

Checking a Saw Cut: How to Measure Correctly

Only the right measurement shows whether a cut is within tolerance.

1. Wait for temperature: Measure only once the part has reached room temperature. The reference temperature is 20 °C.
2. Choose the right gauge: Up to about 1000 mm, a calliper works well. Beyond that, use a class I tape measure or a length measuring device.
3. Don’t measure the burr: Measure on the cut face, not on the burr.
4. Check the angle: A try square or protractor shows squareness and mitre angle.
5. Document the result: For critical dimensions, an inspection report belongs with the delivery.

Our guide to precision measurement shows which gauges suit which accuracy.

How to Specify Cut to Length Tolerances Correctly

A clear specification prevents misunderstandings and queries. These points belong in every order:

• State the nominal dimension with the desired tolerance clearly, for example 1800 ± 1 mm
• Mark critical functional dimensions separately
• Name the standard or tolerance class, such as DIN ISO 2768-1m
• State squareness or mitre angle where they matter
• Describe material, cross-section and length completely
• Specify post-processing such as deburring or milling

The more precise the details, the better the fit. Unclear specifications lead to safety margins. An early check of manufacturability avoids needlessly tight specifications. Our checklist to choose a CNC machining supplier shows what to look for in a partner.

Why a Clear Drawing Helps

A dimensioned drawing is the best basis. It shows all dimensions, tolerances and critical faces at a glance.

So the manufacturer can choose the right process. Queries and errors are thereby avoided.

Sawing and Precision Machining at Vulcanus

Vulcanus combines economical cutting with precise further machining. Our guiding principle Passion for Precision shapes every order.

With our sawing services, we make longitudinal cuts up to 3800 mm, including hardened steels, tungsten and special alloys. Where needed, our CNC milling follows for tight tolerances. So you get the raw cut and the finished part from a single source. This helps especially with long parts, as our guide to CNC machining large parts shows.

We secure critical dimensions with modern measuring technology and document them through our quality control for CNC machining. As a partner for CNC contract manufacturing, we deliver precisely fitting parts with binding deadlines. This makes your sourcing predictable and reliable.

Understand Cut to Length Tolerances and Use Them Well

Deviations in sawing are normal and technically founded. Typical are values in the millimetre range to DIN ISO 2768-1.

Knowing the factors, you specify more wisely and economically. Tight tolerances should stand only where they are needed.

Do you need precise cuts or tight tolerances? Contact Vulcanus for a non-binding consultation.

Frequently Asked Questions About Cut to Length Tolerance Sawing