Werix Metal — precision sheet metal fabrication
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SUB-PROCESS — Threads in Sheet Metal

Tapping & Threaded Holes

Tapping puts an internal thread directly into a sheet metal part, so a screw fastens to it without a separate nut. Form tapping cold-forms the thread in a pre-drilled hole and leaves it stronger than a cut thread, because the metal is displaced rather than removed. Where the sheet is too thin to hold a reliable thread, a rivet nut or a self-clinching nut is inserted instead.

Tap cutting a thread into a sheet metal plate, chips curling from the flutes
Overview

Tapping puts a thread directly into the sheet metal so a screw attaches to the part without a loose nut behind it. Form tapping displaces the metal rather than cutting it away, which leaves a stronger thread than a cut tap in the same hole. Where the sheet is too thin to hold a reliable thread at all, a rivet nut or self-clinching nut is inserted instead. The choice between tapping and inserting is decided by thickness, not by preference.

When is form tapping the right choice?

Form tapping needs enough material around the hole for the thread to form without the sheet deforming, and in practice that means roughly one millimetre of steel or more. Aluminium needs more thickness than steel for the same thread, because it is softer and the thread strips more easily. Where the thickness is there, the formed thread is the better one: the metal is cold-worked as it flows into the thread form, which leaves it measurably stronger and produces no chips to clear.

When is a rivet nut the better answer?

Below the thickness a thread can survive, and anywhere the joint has to come apart repeatedly, a rivet nut or self-clinching nut is the correct specification. The fastener carries the load instead of the sheet, the sheet can be thin, and the result is still a threaded attachment point installed in one press operation. Blind-side access is not required, which matters on a closed enclosure where the back face cannot be reached.

How is thread quality verified?

Thread depth and form are checked with go and no-go gauges, so a thread that is too shallow or damaged is caught here rather than on the customer assembly line. Where a threaded joint carries load, we also run push-out and torque tests on the first article and repeat them whenever the tooling or the material changes.

Does tapping have to happen before finishing?

Yes. Tapping after coating would damage the coating around the hole and expose bare metal, which is exactly where corrosion starts. On parts that will be anodised or plated the thread also grows slightly with the coating thickness, so thread size is specified against the finished dimension rather than the bare one.

Tapping and threaded inserts: design rules

RuleGuidelineFailure mode if ignored
Minimum thickness for form tapping≥ 1.0 mm in steel; more in aluminiumThread strips under load
Hole diameter for form tappingPer the tap maker chart, not a drill chartTorn or oversized thread
Hole-to-edge distance≥ 2 × thread diameterEdge bulge, thread distorts
Thread engagement≥ 1.5 × thread diameter in steelScrew bottoms out or strips
Sheet below the limitRivet nut or self-clinching nutNo reliable thread at any torque

Common questions about Tapping & Threaded Holes

What is the difference between form tapping and cut tapping?

Cut tapping removes metal to create the thread; form tapping displaces it. The formed thread is stronger because the material around it is cold-worked in the process, and there are no chips to clear from blind holes. The trade-off is that form tapping needs a larger pilot hole and more material thickness, since it relies on the metal flowing rather than being cut away.

Can a hole be tapped after powder coating?

It should not be. Tapping through a cured coating damages the coating around the hole and exposes bare metal, creating a corrosion path exactly where moisture collects. The standard sequence is tapping, then deburring, then finishing. Where a thread is needed in a coated assembly, a masked area or a rivet nut installed before coating is the cleaner answer.

How thin can sheet metal be tapped?

Around one millimetre is the practical floor for form tapping in steel, and aluminium needs more because it strips more easily. Below that the sheet cannot support the thread, and the correct specification is a rivet nut, a self-clinching nut or a welded nut. Push-out testing confirms which of those is right for the load on the joint.

Do tapped holes need deburring?

Yes. Tapping raises a burr at the thread entry, and on a part that will be coated that burr also prevents the coating from covering the hole edge evenly. Threads are deburred and cleared before finishing, which is why deburring is specified as the step immediately after tapping rather than as a separate operation ordered later.

Materials we run this process on

304 stainless steel sheet metal
5052 aluminum sheet metal
SPCC cold-rolled steel

Related capabilities and next steps

deburring the hole edge after tapping
hardware insertion where the sheet is too thin
stamped parts that need threaded points
hole and thread design rules
upload a drawing for a tapped part
compare the sheet metal grades we fabricate
DFM checklists and engineering resources
threaded holes and insert cost in sheet metal

Specifications

Thread MethodsCut, form (extrusion), machine tapping
Typical Thread SizesM2 – M12
Min Thickness (form tap)≥ 1.0 mm in steel; more in aluminium
Thin-Sheet AlternativeRivet nuts, self-clinching nuts

Capabilities

Form-tapped threads are stronger than cut threads
Thread depth checked with go / no-go gauges
Rivet-nut insertion where the sheet is too thin to tap
Deburred and cleaned before finishing

Sheet metal engineering guides

DFM for Sheet Metal: Essential Design Rules That Save Cost and Prevent Production FailuresDFM for Sheet Metal: Essential Design Rules That Save Cost and Prevent Production FailuresDesign-for-manufacturing rules for sheet metal — minimum hole sizes, bend radii, edge distances, tab-and-slot design, and common mistakes that cause scrap.Read More8 Proven Ways to Cut Sheet Metal Costs Without Sacrificing Quality8 Proven Ways to Cut Sheet Metal Costs Without Sacrificing QualityFrom bend radius optimization to material nesting — eight actionable design and sourcing strategies that reduce cost while maintaining part performance.Read More

Ready to get started?

Upload your design for a quote with DFM analysis — our engineers respond within 24 hours.

ISO 9001 · Quality Assurance

Checked at every stage

Four-step quality control from raw material to shipment. Precision inspection at every stage. FAI reports provided on request.

WERIX Metal is certified to the ISO 9001 quality management standard.

3,000+ m²
manufacturing space
11+
years
5,000+
clients served
24 h
quote reply
01

Incoming Material

Each batch of raw sheet metal checked for thickness, grade, and surface finish before production begins.

02

In-Process Check

First-article inspection and random sampling at every workstation: laser, bend, weld, stamp.

03

Final Inspection

Dimensions checked against customer drawings. Precision instruments used for tight-tolerance parts.

04

Shipment Audit

Packaging, labeling, and surface protection inspected before dispatch. Each batch traced.

Frequently asked questions

What sheet metal capabilities does WERIX offer?

WERIX runs 17 processes across our own floor and our finishing partners: fiber laser cutting (±0.1mm), CNC bending (±0.5°), TIG/MIG/spot/laser welding, progressive die stamping (±0.01mm), deep drawing and assembly in-house, plus powder coating, anodizing and plating at long-standing licensed partner plants to our specification. Full process list on the capabilities overview.

Does WERIX handle both sheet metal fabrication and metal stamping?

Yes. WERIX is one of few factories offering both sheet metal fabrication (laser cut + bend) and metal stamping (progressive die, transfer die) under one roof with an in-house die workshop.

What tolerances can WERIX achieve?

Laser cutting: ±0.1mm. CNC bending: ±0.5° (±0.1° on new machines). Stamping: ±0.01mm with progressive dies. Welds for food-grade surfaces are produced to AWS D18.1 practice.

Can WERIX produce both a prototype and the production run?

Yes. Prototypes are laser cut and bent with no tooling cost, then the same part moves to turret punching or progressive die stamping once volume justifies the die. One factory, one quality system and one engineering contact cover every stage.

What is the maximum sheet metal size and thickness you can process?

Fiber laser cutting handles sheet up to 5 mm in production and 25 mm at reduced speed; CNC bending supports part lengths up to 2,200 mm with ±0.1° angle accuracy; turret punching covers sheet up to 6 mm. Tell us the part envelope and we will confirm machine fit.

Do you offer surface finishing and assembly in the same order?

Yes, on one purchase order. Hardware insertion, welding, gasket fitting and functional testing are done in-house; powder coating, anodizing, plating, brushing, sandblasting, silk printing and laser engraving are carried out by long-standing licensed partner plants to our specification and inspected by us. You deal with one supplier instead of five.

Is WERIX ISO 9001 certified?

Yes. WERIX Metal is ISO 9001 certified. The quality management system covers incoming material inspection, in-process control at every workstation, final inspection against your drawing and the shipment audit.

Which welding processes does WERIX offer?

WERIX offers TIG, MIG, spot and laser welding, all performed in-house on the same floor as cutting and bending. Spot and laser welding suit thin-gauge enclosures; TIG gives clean cosmetic seams on visible brackets. See the laser welding and TIG welding process pages for tolerances and typical parts.

Do you build and maintain stamping dies in-house?

Yes. Our in-house die design and die maintenance workshop designs, builds and services progressive, transfer and compound dies, so tooling changes never wait on a third party and the die stays matched to our own presses.

What is the largest sheet size you can laser cut?

Production fiber laser cutting handles sheet up to 5 mm thick and 25 mm at reduced speed, on beds sized for full-size sheet. For thicker plate or longer parts, CNC punching and press-brake bending cover the envelope - tell us the part dimensions and we will confirm machine fit on our capabilities overview.

Can WERIX deep draw parts?

Yes. Deep drawing produces seamless cylindrical and box-shaped shells from a flat blank in one progressive sequence, ideal for shielded cans, housings and covers where a welded seam would leak or rust. Send the drawing and we will assess draw ratio and required stations.

When should I choose laser cutting instead of CNC punching?

Use laser cutting for low-volume runs, complex profiles and parts with few repeated features — there is no tooling, so a 1-piece prototype and a 500-piece batch share the same setup. Move to CNC turret punching once the design is stable and the sheet has many identical holes, louvers, tabs or forms, because the punch hits far faster per feature at volume. The crossover is usually in the low thousands of pieces; see our laser vs punch guide for the full decision matrix.

What is the difference between laser cutting and CNC punching?

Laser cutting is a non-contact beam that cuts any 2D profile with no tooling and a 0.1 mm edge; CNC turret punching strikes shaped tools into the sheet, so it is faster for repeated holes and forms but limited to tool geometry. Laser suits prototypes and complex shapes, punching suits repetitive high-volume features. Both feed the same press-brake bending cell, so the part is finished on one floor.

Sheet metal fabrication or CNC machining — which for my bracket?

Choose sheet metal when the part is a thin-walled enclosure, panel, bracket or chassis from 0.3–6 mm stock — it is faster and cheaper to cut and bend than to mill a solid block, and far lighter. Choose CNC machining when you need thick sections, tight 3D tolerances or features sheet metal cannot form. Many parts use both: a machined insert in a fabricated housing. Our sheet metal vs CNC guide walks through the cost and tolerance trade-offs.

Laser cutting, CNC punching or stamping — which process for my part?

Start with fiber laser cutting for prototypes and low volumes, complex profiles or few repeated features — no tooling, ±0.1 mm edge. Move to CNC turret punching once the sheet has many identical holes, louvers or forms and the design is stable, because the punch hits far faster per feature. Move to progressive-die stamping above a few thousand parts a year, where ±0.01 mm repeatability and the lowest unit cost justify the die. All three feed the same press-brake cell, so the part is finished on one floor. See the laser vs punch guide for the crossover numbers.