Tap drill · pull-out screening

Thread pilot & engagement

Inputs

Metric thread major diameterDmajorUser-entered nominal major diameter; no thread standard or class is selected.

Thread pitchPUser-entered compatible metric pitch.

User-stated tap engagementE%Target tap engagement fraction from 0 to 100%; it is not measured actual engagement.

Thread engagement lengthLeUser-entered axial length of engaged threads for the simplified screening area.

Thread frequencynTPIUser-entered thread count per inch required by the reviewed root-shear-area equation.

External minimum major diameterDsminUser-entered external-thread minimum major diameter for the reviewed root-shear-area equation.

Internal maximum pitch diameterEnmaxUser-entered internal-thread maximum pitch diameter for the reviewed root-shear-area equation.

User-stated internal-thread allowableτallowUser-entered shear allowable for screening only; material and standard selection are excluded.

Applied axial loadFUser-entered direct axial load for the simplified pull-out utilization output.

Results

Target tap drill at stated engagement

8.875

Basic major-minus-pitch drill

8.5

Engaged thread pitches

—

Reviewed root-shear area

202.37

User-property thread-stripping capacity

18,213

Applied load / screening capacityU

24.707

Dtap = Dmajor − P·E; Ats = πnLeDsmin[1/(2n)+0.57735(Dsmin−Enmax)]; Fscreen = Atsτallow

A first-pass number, not a code check, certification, or approval. Read the method and its limits below. What this is and is not.

Calculation snapshot

Thread pilot & engagement

Formula version 2.0.0

Conditions

Metric thread major diameter	10
Thread pitch	1.5
User-stated tap engagement	75
Thread engagement length	12
Thread frequency	20
External minimum major diameter	0.248
Internal maximum pitch diameter	0.2175
User-stated internal-thread allowable	90
Applied axial load	4500

Calculated response

Target tap drill at stated engagement	8.875 mm
Basic major-minus-pitch drill	8.5 mm
Engaged thread pitches	8 —
Reviewed root-shear area	202.37 mm²
User-property thread-stripping capacity	18,213 N
Applied load / screening capacity	24.707 %

Method

Dtap = Dmajor − P·E · Ats = πnLeDsmin[1/(2n)+0.57735(Dsmin−Enmax)] · Fscreen = Atsτallow

Source

FED-STD-H28, Screw-Thread Standards for Federal Services (public domain):

Boundaries

Metric major diameter and pitch
User-stated engagement fraction
Reviewed root-shear inputs
Direct axial stripping screen only

This printout is a record of displayed inputs and deterministic formula output. It is not an approval, certification, or engineering conclusion.

Nearby: Milling removal rate · Drilling speed & time · Turning material removal · Milling cutting parameters

Method

Formula, when it applies, and when it does not

Calculate a basic metric tap drill, engagement length, and a reviewed root-shear-area thread-stripping screening value from dimensions.

Dtap = Dmajor − P·E; Ats = πnLeDsmin[1/(2n)+0.57735(Dsmin−Enmax)]; Fscreen = Atsτallow

When

Metric major diameter and pitch
User-stated engagement fraction
Reviewed root-shear inputs
Direct axial stripping screen only

Don’t

This combines source-stated basic metric tap-drill arithmetic with the reviewed internal-thread root-shear-area relation using user-entered TPI, minimum external major diameter, maximum internal pitch diameter, engagement length, and shear strength. It does not select a thread standard, fit/class, drill, tap, material, allowable, or actual engagement; it excludes load distribution, bending, fatigue, torque/tension interaction, thread damage, installation effects, joint stiffness, and acceptance/compliance.

FED-STD-H28, Screw-Thread Standards for Federal Services (public domain)