Segmented Woodturning Symposium October, 2018 James Rodgers Open Segment Woodturning An overview of techniques Part One - PReparing Segmented Woodturning Symposium October, 2018 James Rodgers

Open Segment is “GAPS” Pieces are not assembled in a “ring” Can be very small to very large Using small colored pieces creates complex designs

The Basic Reference Published on 2002

Dennis Keeling book Published in 2012 Focus on open segment construction Contains basic information on the SegEasy plate use

My Book Published 2016 for SWT symposium Covers Basics Open Segment construction Seg Easy Dizzy bowls Segment pens Feature ring designs

Basic terms Segment Width Segment Edge Length Segment/Board thickness

Basic terms Segment total angle Actual cut angle

Simple math Segment edge length = Circumference ÷ # segments

Segment included angle Simple math Segment included angle = 360 degrees (circle) ÷ # segments Segment cut angle is ½ of above Segment included angle

Math example Ring diameter is 10 inches We desire 12 segments / ring

Math example Ring diameter is 10 inches We desire 12 segments / ring Diameter 10 x 3.14 (π) = 31.4 inches Circumference

Math example Ring diameter is 10 inches We desire 12 segments / ring Diameter 10 x 3.14 (π) = 31.4 inches Circumference Segment edge length 31.4 ÷ 12 = 2.6 inches

Math example Ring diameter is 10 inches We desire 12 segments / ring Diameter 10 x 3.14 (π) = 31.4 inches Circumference Segment edge length 31.4 ÷ 12 = 2.6 inches Segment included angle is 360° ÷ 12 segments = 30°

Math example Ring diameter is 10 inches We desire 12 segments / ring Diameter 10 x 3.14 (π) = 31.4 inches Circumference Segment edge length 31.4 ÷ 12 = 2.6 inches Segment included angle is 360° ÷ 12 segments = 30° Segment cut angle is 30° ÷ 2 = 15°

We need a Shape!

We need a drawing!

Add ring thicknesses Ring (stock) thickness

Calculate segment width OR-IR = Segment Width Outside Radius Inside Radius

Now we have all the dimentions Segment Width Segment Edge Length Segment/Board thickness Segment cut angle

Ring segment construction Segment edge length Ø = 10 inches 12 segments Cut angle = 15º Segment edge = 2.6” Cut angle

Open segment construction Segment edge length Ø = 10 inches 12 segments 30% gap Included angle 30º - 9º = 21.º (30% of 30º = 9º) Cut angle 21º ÷ 2 = 10.5º Segment edge 2.6” x 70% = 1.8” Cut angle

Indexing options – home made

Alisam Engineering indexing Includes magnetic locking arm 90, 120, 144 index 2.5º, 3º, & 4º All spindle sizes $89.99 Alisam.com

Version for small lathes also Jet mini version $54.99 20 & 72 holes

Iron Fire version Includes wheel and pin only 14, 36, 48, 60 holes $24.99 all spindle sizes Ironfirellc.com

Indexing diagrams From Bill Smith’s Book 12 – 144 divisions Positioning jig drawings On line at: www.segmentedwoodturners.org/projects

Smith basic jig For on-lathe use only Easy to build Requires no special accessory Details in Smith’s book

Driskell Design For off-lathe construction Requires custom threaded fitting Uses gravity to help Projects need to be re-aligned after on lathe work Much faster

SegEasy plate 18 & 24 segment versions Fixed 4º spacing All segments at once Required precise thicknesses Lloyd Johnson modification for alignment $49.95 @ dealers

Designing the vessel First create a shape

Determine project parameters Project/stock size Number of segments

Determine project parameters Spacing between segments Design choices

Create a cut list

JLR custom calculator

For open segment work I added “radius”

Rip stock to width

Number all strips

Make an “adjustable” cutting sled

Each angle requires a separate stop

Always use a hold down

Purchase and adjustable sled

Cut segments

Every segments must be sanded

Project components ready