1. Tom Russell
Big Island Ukulele Guild
SEGMENTED
ROSETTES

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

12. A Segment!

13. 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” ÷ ≈ /16” Round up to 7/8”

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

15. 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 /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

16. Segmented Rings Website for Calculations A bit of wisdom
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.

17. 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

18. Cutting Segments “Auto” Angle Error Correction 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

19. Cutting Segments Grain Matching + Color & Pattern Matching! More Wood
Segments must be accurate.
Careful cutting of “throw-away” pieces can make some interesting designs when doing laminates or mosaics

20. 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

21. 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

22. 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!

23. 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

24. 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.

25. 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

26. Laminations

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

28. 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

29. 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!