Tangents- Definition Geometric Constructions A line is a tangent to a circle if it touches the circle at only one point

Tangents- Definition Geometric Constructions Two curves are tangent to each other if the touch in one and only one place

Geometric Constructions Tangents- Geometric location of tangent point The tangent point of a straight line and circle will lie at the intersection of a perpendicular to the straight line that passes through the center of the circle.

Geometric Constructions Tangents- Geometric location of tangent point The tangent point of two circles will lie on the circumferences of both circles and on a straight line connecting the circle centers

Straight Line Tangents to a Circle from an External point Geometric Constructions Tangents- Construction

Straight Line Tangents to a Circle from an External point Geometric Constructions Tangents- Construction

R r R-r Common Parallel Straight Line Tangents to Two Circles of Radius ‘R’ and ‘r’ Geometric Constructions Tangents- Construction

R r Common Parallel Straight Line Tangents to Two Circles of Radius ‘R’ and ‘r’ Geometric Constructions Tangents- Construction

R r R+r Common Cross Straight Line Tangents to Two Circles of Radius ‘R’ and ‘r’ Geometric Constructions Tangents- Construction

R r Common Cross Straight Line Tangents to Two Circles of Radius ‘R’ and ‘r’ Geometric Constructions Tangents- Construction

R R R R Circular Tangent of Radius ‘R’ Between a Point to a Straight Line Geometric Constructions Tangents- Construction

RR R R R Circular Tangent of Radius R Between Two Straight Lines at an Angle Geometric Constructions Tangents- Construction

R R R R+r r R R R Internal Circular Tangent of Radius ‘R’ Between a Straight Line and a Circle of Radius ‘r’ Geometric Constructions Tangents- Construction

R R R R-r r R R R External Circular Tangent of Radius ‘R’ Between a Straight Line and a Circle of Radius ‘r’ Geometric Constructions Tangents- Construction

R+r1 r2 R+r2 R r1 R+r1 R+r2 R Internal Circular Tangent of Radius ‘R’ Between Two Circles of Radius ‘r1’ and ‘r2’ Geometric Constructions Tangents- Construction

R-r1 r2 R-r2 R r1 R-r1 R-r2 R External Circular Tangent of Radius ‘R’ Between Two Circles of Radius ‘r1’ and ‘r2’ Geometric Constructions Tangents- Construction

R-r1 r2 R+r2 R r1 R-r1 R+r2 R Cross Circular Tangent of Radius ‘R’ Between Two Circles of Radius ‘r1’ and ‘r2’ Geometric Constructions Tangents- Construction

Basic Sketching Line types Visible Object – Thick Visible Edges and Outlines Hidden – Thin Hidden detail for like wall thickness and holes.. Center - Thin centre of a circle, cylindrical features, or a line of symmetry. Geometric Constructions 1mm 3mm 1mm 3mm 15-20mm 0.7mm HB 0.3mm 2H 0.3mm 2H

Line Types An Example: 1. Visible 2. Hidden 3. Center Geometric Constructions

Intersection of Lines Solid Line Intersections Dashed Line Intersections Gap Geometric Constructions

Hidden Line Conventions Geometric Constructions

Hidden Line Conventions Geometric Constructions

Centerline Conventions Extend 5mm Geometric Constructions

Lettering : Basic Strokes StraightSlantedCurvedHorizontal “I” letter “A” letter “B” letter Examples:

Geometric Constructions Lettering : Upper Case & Numerals

Geometric Constructions Gothic vertical style. Always use capital letters. Text height 3~5 mm. Space between lines of text is about of text height. Lettering : Rules Space between words equal to the space required for writing a letter “O”. Example: ALLDIMENSIONS ARE IN MILLIMETERS O O O O UNLESS OTHERWISE SPECIFIED. O

85 R100 R85 85 R100 R85 R70 Tangents- CW 1 Geometric Constructions

R=44 R=18 R=16+19=35 R=16 R=8 R=22-5=17 R=22+5=27 R=19 R=18+22=40 R=44+22=66 R=19

Geometric Constructions