Tom Russell Big Island Ukulele Guild SEGMENTED ROSETTES

Segmented Rosettes An easy way to get some creativity in your builds A bit of Math…Sorry Cutting Segments Gluing Up Tricks Laminates & Mosaics

A Segment!

Segment Edge Length Example: 3 Inch, 12 Segment Rosette Circumference ÷ # of Segments Circumference = Diameter × π 3 × 3.14 = 9.4” Circumference Segment Edge Length = 9.4” ÷ 12 ≈ 13/16” Round up to 7/8”

Segment Cut Angle Math 3 Inch 12 Segment Rosette Segment Total Angle = 360° CIRCLE ÷ # of Segments 360 ÷ 12 = 30 ° Angle Segment Cut Angle = Segment Total Angle ÷ 2 30 ÷ 2 = 15° Cut Angle Segment Total Angle Segment Cut Angle ½ Total Angle

OUR SEGMENT! Segment Edge Length = 7/8 “ Segment Cut Angle = 15° Segment Width = 3 /4 “ Segment Depth = 3 /4 “ Segment Width = Just make it wider than width of rosette wall 3/8” Wall  ¾ Inch Gives plenty of room for errors Make Segment Depth ¾” or greater to make more than 1 rosette at a time

Segmented Rings Website for Calculations A bit of wisdom http://marleyturned.com/Shop_Utilities.html A bit of wisdom Add 3 to 4 inches extra to the blank length (no bloody fingers) Add even more to the length to make a coupe of extra segments Mark the wood blank with a diagonal line on the “top” side when segment order is important. Makes it easy put the segments back in order.

Cutting Segments Accuracy is very important 12 Segmented Ring has 24 angle cuts (2 per segment) A 0.1° error, or 15.1° cut adds 2.4° to the circle makes a 360° ring a 362.4° ring! Choice of gluing method hides imperfections ChopSaw Accuracy? Angled Tablesaw Blade Tricky! Miter on Tsaw 0.5” “Accuray” (?) Probably needs tweaking Segment Miter Tool Alternative to Incra Pricey Dedicated Sled Crazy Accurate One per Segment Size

Cutting Segments “Auto” Angle Error Correction 1 2 3 4 5 6 7 8 1 2 3 4 5 6 7 8 Economy Mode Flip board stock over after every cut + Saves wood! - Color & Grain may vary between segments (not a bad thing) “Auto” Angle Error Correction Number each segment or use the diagonal line method to keep track of segment cut order. Flip even number pieces over when making ring to negate angle errors! 14.9 ° 15.1 ° 30.0 ° 1 2

Cutting Segments Grain Matching + Color & Pattern Matching! More Wood Segments must be accurate. 1 2 3 4 5 6 7 8 Careful cutting of “throw-away” pieces can make some interesting designs when doing laminates or mosaics

Gluing Segments Two at a time “Rub Method” Use when segment-to-segment alignment is critical (eg mosaics) Build up to “half rings” Allows final tweaking of ring Use rubber bands to hold each pairing in place until set

Gluing Segments Half Rings Excellent choice when using miter saw or other methods without 100% accurate angle cuts Glue up half rings any way you want Two at a time (mosaics!) OR “All at once”. LIGHTLY touch up half rings on Disc Sander for perfect half rings Makes a poor, ill-fitting ring PERFECT! Severely poor angles may result in a “squished circle”. Might be ok, but just improve your setup! Add dowels with one flat side to each half ring

Gluing Segments Other Glue Methods All At Once Whatever Must have good sled & have perfect rings Recommend Hose Clamps Whatever Fretboard covering the top? Who Cares! But cut angle must be less than target!

Gluing Segments Summary Hose Clamps! Rubber Bands of too. Dry Fitting always a good idea If fit isn’t perfect, try “Half-Ring” Glue-up Method Glue Methods Two at a time “Rub Method” Half Rings – Always Perfect All At Once Whatever

Tricks Add Spacers between segments Just reduce segment length by width of spacer Add spacer to the same side of every segment Makes the half-ring method tricky OD 4 “ 1 3/8” Seg Len. 1/8” Spacer OD 4 “ 1.5” Seg Len.

Tricks Make mosaics! Grain Matching is best for segment-to-segment design continuity Consider spacers depending on design Attempt to maintain grain orientation within the mosaic

Laminations

Advanced Laminations Usually Cut “Grain Matching” 30 ° Cut Angle Accuracy!

Tips & Tricks Even segment numbers provide symmetry But numbers like 7 work nicely too! When gluing, keep points of segment aligned to insure “roundness” Use graph paper to make designs Don’t make solid rings! # of Cut Segments Angle 8 22.50 9 20.00 10 18.00 12 15.00 15 12.00 16 11.25 18 10.00 20 9.00 24 7.50 25 7.20 30 6.00 36 5.00

Make Circles! Make the rosette blank about 1/8” thick or so Use your favorite Rosette cutter – STEW-MAC Draw segment ring ID & OD diameters centered around circle cutter center Double Stick Tape is your friend Pau!