Manufacturing Standards
TOLERANCES
Standard Tolerances
Standard Cutting Tolerances (unless otherwise specified on the drawing)
Parts up to 24" × 24"
Profile / Outside Contour:±0.010."
Hole Sizes:±0.005"
These tolerances apply to metal, plastics, and composites unless a custom quote specifies otherwise.
Size-Based Adjustment Rule
Larger Parts = Profile Tolerance Increases
For parts larger than 24" × 24", profile tolerance increases with size:
For every additional 12 inches of part size beyond 24", add ±0.002" to the profile tolerance.
We can support part sizes up to 58" × 118".
Hole Tolerances (Thickness-Based) + Notes
Hole Tolerance Rule (does NOT change with part size)
Standard hole size tolerance is ±0.005"
Hole tolerance may require adjustment when material thickness is above ~0.750"
Important notes
These are standard cutting tolerances and assume typical geometry, material flatness, and feature access.
If you have critical dimensions, call them out clearly on the drawing.
Tighter tolerances are available via custom quoting.
Instant Quote limitation (materials)
Our Instant Quote platform currently does not support quoting rubber, foams, or plastic materials other than Acrylic.
For these materials, please request a custom quote.
INSPECTION & AQL (AQL 4.0 / GENERAL II)
What we inspect (default)
Default Inspection Standard:AQL 4.0 — General Inspection Level II (General II)
This means we inspect a statistically valid sample from each lot to verify conformance to the drawing and the agreed requirements.
What we check (typical):
Overall dimensions and critical features called out on the drawing
Hole sizes / feature sizes (as applicable)
Visual condition (burrs, edge condition, obvious defects)
Part count and labeling match the order
If your part has critical-to-function dimensions, call them out clearly on the drawing so they are included in inspection focus.
Documentation available (CofC + Material Certs)
CoC (Certificate of Conformance)
Available on request. Confirms parts were produced to the specified drawing/revision and purchase order requirements.
Material Certs / Mill Test Reports (MTRs)
Available on request for materials where traceability is required. We can provide material certs tied to the heat/lot where applicable.
AQL 4.0 / General II — Lot Size → Sample Size (Normal Inspection)
2–8 pcs → inspect 2
9–15 pcs → inspect 3
16–25 pcs → inspect 5
26–50 pcs → inspect 8
51–90 pcs → inspect 13
91–150 pcs → inspect 20
151–280 pcs → inspect 32
281–500 pcs → inspect 50
501–1,200 pcs → inspect 80
1,201–3,200 pcs → inspect 125
3,201–10,000 pcs → inspect 200
THREADS + TAPPING
What we support (standard):
UNC / UNF (inch) and Metric (M) threads
Through and Blind tapped holes (blind requires thread depth callout)
How to call it out on a drawing (required):
Thread size + pitch
Through or blind
Thread depth for blind holes
Quantity (if multiple)
Examples:
1/4-20 UNC-2B THRU
10-32 UNF-2B x .375 DP
M6 x 1.0 - 6H THRU
M8 x 1.25 - 6H x 12mm DP
Standard Inch Tap Sizes (UNC / UNF)
Common shop standard sizes:
#4-40, #6-32, #8-32, #10-24, #10-32, 1/4-20, 1/4-28, 5/16-18, 5/16-24, 3/8-16, 3/8-24, 1/2-13, 1/2-20, 3/4-10
Notes:
If the drawing does not specify thread depth for blind holes, we will request clarification before production.
For tight tolerance threaded features or critical fit, call out the class (inch) or tolerance (metric), and any gaging requirements.
If you need a thread that isn’t listed above, include it on the drawing—we can review by custom quote.
Standard Metric Tap Sizes
Common shop standard sizes:
M3 x 0.5, M4 x 0.7, M5 x 0.8, M6 x 1.0, M8 x 1.25, M10 x 1.5, M12 x 1.75
Notes:
If the drawing does not specify thread depth for blind holes, we will request clarification before production.
For tight tolerance threaded features or critical fit, call out the class (inch) or tolerance (metric), and any gaging requirements.
If you need a thread that isn’t listed above, include it on the drawing—we can review by custom quote.
COUNTERSINKS
Countersink Standards
Standard countersink angles supported by ACP:
82° — common for inch flat head screws
90° — common for metric and general-purpose applications
100° — common for aerospace and specialty applications
For best results, please specify:
Countersink angle
Hole size
Major diameter, if critical
Hardware type, if fit is important
Uncommon angles or special fit requirements are reviewed on a case-by-case basis.
DEBURRING
Deburring & Edge Finishing Capabilities
All parts are delivered burr-free with edges broken for safe handling.
ACP supports:
Up to 47" wide automated edge deburring
Orbital finishing (no size limitation)
Manual deburring for plastics and composites
STOCK MATERIALS
Materials We Stock
ACP maintains in-stock inventory for the most commonly used materials to support fast turnaround.
Metals (Stocked):
Aluminum — 0.032" to 1.00" thick
Steel — 0.032" to 1.00" thick
Stainless Steel — 0.032" to 1.00" thick
Plastics (Stocked):
Acrylic
Additional Materials Available
We can quickly source a wide range of materials beyond our standard stock, including:
Rubber
Foam
Composites
Specialty plastics
Other alloys and grades
If your material is not listed, contact us — most materials can be sourced with minimal lead time.
FILE GUIDELINES
File Guidelines for Accurate Quotes
To ensure fast and accurate quoting, please follow these guidelines when submitting files:
Preferred File Types
STEP (.STEP, .STP) — Recommended
DXF (.DXF)
DXF File Requirements
1:1 scale (full scale only)
No dimensions on the drawing
One part per file (no multi-part layouts)
Do NOT send nested sheets
Remove duplicate or overlapping lines
Countersinks: remove extra circles (single profile only)
STEP File Requirements
Fully modeled part
Include all features (holes, bends, etc.)
No additional cleanup required
General Guidelines
One file per part
Ensure geometry is clean and closed
Avoid sketch-based or incomplete profiles
⚠️ Common Issues That Delay Quotes
Files not at 1:1 scale
Nested layouts instead of single parts
Double lines or open contours
Countersinks shown as multiple circles in DXF
Dimensions included in DXF files