Teaching STEM Through Electric Guitar Design Molly Reich and Gary Mahoney
Goals of this presentation: Electric Guitar History Critical Design Considerations Electric Guitar Designing with CAD Electric Guitar Production
Fender Telecaster Tele First electric guitar to be industrially manufactured Solid body Available with 1 or 2 single coil pickups Dual are most common Produced since 1950s
Gibson Les Paul Designed by Ted McCarthy Endorser by Les Paul Produced since 1952 Maple and Mahogany construction Humbucker pickups
Fender Stratocaster Strat Fender s second big success Three single coil pickups Produced since 1954
Gibson SG Designed by Ted McCarthy Introduced in the early 60 s Lighter Body Solid Mahogany construction P90 or Humbucker pickups
PRS Designed by Paul Reed Smith Produced since 1985 Maple and Mahogany construction Humbucker pickups
Others
Understanding some design physics Vibrating string length Fret locations Pickups Types of bridges Wood Nut size String spacing String break angle
Scale Length (Vibrating String Length) Martin Guitars 25.34 Gibson 24.562 Fender 25.5 PRS 25 http://www.stewmac.com/materials_and_supplies/bodies_and_necks_and_wood/archtop_guitar/fingerboards/slotted_fingerboard_for_fender_guitar.html
Calculating Fretting positions 12th root of 2 1.0594631 F 698.45645 Hz F# 739.98883 Hz G 783.99085 Hz 739.98883/698.45645 = 1.059463 Rule of 18 17.817 A 440.00000 Hz A# 466.16376 Hz B 493.88330 Hz C 523.25113 Hz C# 554.36526 Hz D 587.32953 Hz D# 622.25396 Hz E 659.25510 Hz F 698.45645 Hz F# 739.98883 Hz G 783.99085 Hz G# 830.60937 Hz A 880.00000 Hz http://homepage.ntlworld.com/coleman005/fretting%20calculations.htm
Calculating Frets http://www.stewmac.com/fretcalculator
Pickups Fixed distances Neck and Bridge http://www.stewmac.com
Single Coil Pickup 6 Permanent Magnets Copper coil 42 gauge (.063mm) most common Thousands of windings 7 10K typical Produces a bright, clear sound
Humbucker pickup Two coils Wired in series Single magnet Coils become poles Coils are wound opposing String current is additive Noise is canceled Produces a darker, bassier sound
Volume and Tone Volume and Tone Control Connected in Parallel Tone Control Treble bleed tone control Pot with Capacitor Capacitor functions as a high frequency resistor
Not Much Room
Pick-up Insert
Jimmy Page Setups
Basic Bridges (fixed distances) Telecaster Stratocaster Trem Hardtail Gibson Tune-a-matic Floyd Rose
Hardtail Bridge http://www.stewmac.com/hardware_and_parts/bridges_and_tailpieces/electric_guitar/gotoh_hardtail_bridge.html
Stratocaster style Trem bridge http://www.stewmac.com/hardware_and_parts/bridges_and_tailpieces/electric_guitar/gotoh_traditional_tremolo_for_strat.html
Telecaster bridge http://www.stewmac.com/hardware_and_parts/bridges_and_tailpieces/electric_guitar/gotoh_modern_bridge_for_tele.html
Tune-o-matic Bridge Stop Tailpiece http://www.stewmac.com/hardware_and_parts/bridges_and_tailpieces/electric_guitar/nashville_tune-o-matic_bridge.html
Woods Solid Laminated African Mahogany Alder Curly Maple
Figured Woods
Shrinkage and Stability
Selection of Cut
Nut Size and String Spacing http://www.stewmac.com/how-to/online_resources/nuts_and_saddles/slotted_bone_nuts_sizing_sheet.html
Drawing the Nut
String Spacing
Basic Peg Head Shapes String Angle Break Angle http://www.chubbuckguitars.com/blog/2013/01/02/1979-strat-getting-back-to-stock
Peg Head Layout
Angled Neck for Break Angle Around 12 Degrees
1 Thick Neck with Guides or Keepers.
Critical Design Considerations: Design Considerations: Vibrating string length Number of frets Bridge Type Nut Width Criteria for Our Design: Vibrating string length 25.5 Number of frets 22 Bridge Type Trem Bridge Nut Width 1 13/32
Critical Geometry Stratocaster
Hybrid Methods CNC Machine Critical Features into a block of wood and then finish with traditional tools Without CNC equipment: use handheld router with a rub collar. Guide can be laser cut
Outline Removed
Rub Collar
Cutter Diameter (.5 ) minus Rub Collar Diameter (.625) divided by 2 equals.0625 (offset Diameter).
Rub Collar Method
Free Hand Sculpt Method
Free Hand Sculpt Method
CAD Modeling the Neck: Challenges Free online files are merely renderings Joint areas are a mesh Drawings contain insufficient dimensions for reproduction
CAD Modeling the Neck
Loft then Move Face
CAD Modeling the Neck: Back profile
CAD Modeling the Neck: Back Profile
Fillets
Fillets
CAD Modeling the Neck
CAD Modeling the Neck Peg Head Body Joint Truss Rod Adjuster Nut
CAD Modeling the Body
Fusion 360
Fusion 360
Fusion 360
Fusion 360
Fusion 360
Fusion 360
Fusion 360
Fusion 360
Fusion 360
Fusion 360
Fusion 360
Fusion 360
Fusion 360
Fusion 360
Fusion 360
Fusion 360
Fusion 360
Fusion 360
Fusion 360
Fusion 360
Fusion 360
Fusion 360
Fusion 360
Production
Production
MasterCAM Toolpaths
CAM Toolpaths
Test Cuts
Test Cuts
Test Cuts
Tool Types
Refining Toolpaths Sequence of Operations Tool Types
Refining Toolpaths Body Joint
Neck Fixtures
Fixtures: T-Nuts
Machining the Back
Questions?
Thank You Molly Reich reichm@berea.edu Gary Mahoney mahoneyg@berea.edu