Drill Point Length Calculator

Inputs

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Drill body diameter. The cone point length scales directly with diameter.
mm
Included point angle at the drill tip. Common twist drills are 118 degrees or 135 degrees.
°
Depth that must be at full drill diameter. The point length is added to get total drilling depth.
mm

Results

Default result
Edit inputs
Point length(L_p)
3.004mm
Pass

Add this to the required full-diameter depth for a blind hole.

Axial length of the conical drill point.

Also computed

Total drill depth(H + L_p)23mm

Programmed depth to get the entered full-diameter depth.

Half angle(A/2)59°

Method notes 3 notes
  • Drill point length is Lp = (D/2)/tan(A/2), where A is the included point angle.
  • For blind holes, total drilling depth = required full-diameter depth + point length.
  • This assumes a sharp conical drill point. Split points, web thinning, tip flats, regrinds, center drills and drill wander can change the practical allowance.

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