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Precision hole prepXeon NC · Sheet metal

Countersinking.

Make room for a flush fit. Conical seats machined into your sheet metal for flat-head screws, rivets, and recessed hardware. See a countersunk aluminum plate made by Xeon NC.

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Countersinking sheet metal at Xeon NC
Inside the process
A clean seat. A flush finish.
Standard inch seat
82°
Metric seat
90°
Inch fastener range
#4–¼ in

100° seats available on request. See specifications for thickness and geometry requirements.

02 / PrecisionEngineering guide

A clean seat.
A flush fit.

Controlled depth stops keep the seat consistent from hole to hole, with the countersink centered on the pilot hole.

±0.003″Standard depth tolerance
  • Depth control: ±0.003″ — consistent seat across every hole in the part
  • Concentricity: CS axis aligned to pilot hole within 0.002″ TIR
  • Surface finish: clean cone walls, no burr at crest or opening
Countersunk holes in an aluminum part
Depth control · Concentric seats
03 / Seat anglesView size chart

Match the seat.
To the fastener.

Choose the included angle specified for your hardware. Our two standard angles cover inch and metric flat-head screws; 100° seats are available on request.

Standard
82°

Standard inch

For standard inch flat-head machine screws, #4-40 through ¼-20.

Standard
90°

Metric

For ISO metric flat-head screws, M2.5 through M6.

On request
100°

Wide-angle / rivet

For rivets that specify a wider seat. Include the angle in your drawing notes.

Check sheet thickness and countersink fit Preview countersink geometry Compare fastener sizes Explore countersinking benefits
04 / MaterialsExplore stocked gauges

The right metal.
Room for the seat.

Countersinking is available across our standard sheet metals. Thickness requirements vary; we review your geometry at quoting.

  • Aluminum 5052-H32 & 6061-T6 — ideal, clean walls, no burr
  • Steel A1008 & A36 — full range of sizes, slight burr clearance added
  • Stainless 304 & 316 — available, tool-wear managed in-house
  • Brass & Copper — available on request; specify on drawing
  • Minimum recommended material thickness: 2× fastener head height
Countersinking in sheet metal
Material thickness · Fastener fit
05 / SpecificationsOpen geometry calculator

Design with
the details.

Review seat angles, thickness, and file requirements before quoting your part. Include any special requirements with your drawing.

Angles Available
82° (standard inch), 90° (metric), 100° (wide/rivet — upon request)
Fastener Size Range
#4 through ¼″ (inch) · M2.5 through M6 (metric)
Depth Tolerance
±0.003″ standard · Tighter on request (reviewed per geometry)
Min. Material Thickness
Aluminum: 0.063″ minimum · Steel/Stainless: 0.060″ minimum
General rule: ≥ 2× fastener head height
Compatible Materials
Aluminum 5052/6061 · Steel A1008/A36 · Stainless 304/316 · Brass (request)
Max Holes per Part
No hard limit — large quantities handled on standard run time
File Requirements
Mark CS holes in DXF with diameter + angle note, or call out on drawing. We can also follow a hole chart.
Lead Time
Same as base order — countersinking adds no lead time to standard 3–5 day production
06 / Design tipsRead the design guide

Call it out.
Get it right.

Make the seat diameter, angle, and side clear in your file and drawing.

  • Mark CS diameter in DXF: draw the countersink as its maximum diameter at the surface — not the pilot hole diameter
  • Add a note: include angle (82° or 90°) and fastener size in drawing notes or a hole table
  • Check material thickness: flag any holes in material thinner than 0.063″ — we'll review those at quoting
  • Edge distance: keep CS center ≥ 2× major diameter from any part edge to avoid breakout
  • Stack-ups: if countersinking both sides, note it explicitly — the default is single-side only
  • Post-anodize: anodize after countersinking; Type II coating adds ~0.0002″ and will not affect seating
Countersink dimensions in a CAD design
Diameter · Angle · Countersink side
07 / Stock listFull sheet metal catalog

Find your alloy.
Check your gauge.

Each thickness shows the largest flat head that leaves land under the cone and the angle it uses. Select a gauge for its full material specifications.

Browse the sheet metal catalog for stocked gauges and material specifications.

Filled chips show the largest head and angle that fit.Dashed chips are below the minimum thickness: 0.063″ aluminum · 0.060″ steel and stainless.
Your next part starts here

Finish flush.
Start with your file.

Upload your part file and call out the countersink holes, seat angles, and fastener sizes for your assembly.

Quote your parts
Engineering guide