Orchestrelle Feature Article - It's a book!
Rebuilding the Æolian Orchestrelle 58-Note Player Reed Organ, 1912 Model "W" -- by Richard Vance

Restoration Techniques:
Etched Brass Name Plate for Regina Musical Box  -- by Craig Smith (110318 MMDigest)
Replicating Aeolian Lithographed Celluloid Nameplates -- by Richard Vance
"Roosevelt" Type Font for Aeolian Organs -- by Robbie Rhodes
Making a New Bottom Board for an Upright Piano -- by David Vanderhoofven, RPT (030604 MMDigest)
Recovering Player Piano Bellows -- by John A. Tuttle (040308 MMDigest)

Music Boxes & Organettes:
A unique music box movement (the "DDR movement") -- by Hauke Marxsen
How To Make a Regina Coin Mechanism -- by Bill Wineburgh (010708 MMDigest)
Polyphon Top-Mounted Dampers -- by Craig Smith (001111 MMD)
Mignon 22-note Reed Organette -- text and drawings by Hans van Oost
Inversus: Sankyo 20-Note Moebius Strip Plays Inverse Music -- by Roland Tremblay (030204 MMDigest)
Retrograde Music for Sankyo 20-Note Paper Strip Movement -- by Roland Tremblay (030228 MMDigest)

Organs:
Manischewitz Wine Bottle Organ -- by Phil Dayson (120828 MMDigest)
Inventor L. B. Doman & The Maestro Co., Elbridge, New York -- documents courtesy Dave Kerr
65- & 69-key Gebruder Bruder Organs in America -- by Jeff Alterman (001213 MMD)
The Leach & Overington 89-Key Concert Organ -- by Andrew Leach (030225 MMDigest)
Aeolian Pipe Organ Plays Duo-Art Music -- pictures courtesy Paul Morris
Making Brass Flat Wire for Organ Barrel Pins -- by Craig Smith (090711 MMDigest)
Key Adjusters for Poirot Mirecourt Organ -- by Craig Smith (090817 & 090819 MMDigest)

Wurlitzer:
Wurlitzer Company Records
Wurlitzer Band Organ Factory Ledgers -- by Matthew Caulfield (080212 MMDigest)
Wurlitzer 125 Band Organ -- compiled by Robbie Rhodes
Wurlitzer 165 Band Organ Specification -- compiled by Robbie Rhodes
Wurlitzer Long Roll Tracker Frame -- image files from U.S. Patent Office
Instructions for Tuning Military Band Organs -- courtesy Matthew Caulfield
Make Wurlitzer Valves With "Pem" Fasteners -- by Don Teach (040816 MMDigest)

Gages & Testing & Test Instrumentation:
Manometer Vacuum Gage With Water Trap -- by Richard Vance (MMD 060123)
Leak Meter -- by Johan Liljencrants.  A simple low-rate air flowmeter you can make yourself.
Testing Pouch Leather Sealants -- by Craig Smith   (000721 MMD)

Pipes:
Dimension Tables for Band Organ Pipes -- by Marc Elbasani
How to Make Harmonic Freins -- by Marc Elbasani
Simplified Reed Pipe Construction  -- by Marc Elbasani
Build a Simple Organ Pipe,  "A cross between a flute and a pennywhistle" -- by John Kleinbauer
"No Arithmetic" Flute Pipe -- by Vicki Webb (PDF file, 156 kb)
Organ Reed Pipe Tongue Dimensions -- by Johan Liljencrants (MMD 010125)
Recipe for Wooden Organ Flue Pipes, with Designers Formulæ, Spreadsheet and Measurements -- by Johan Liljencrants
Tremolo and Vibrato Sounds -- by Johan Liljencrants
Ising's formula for pipe-mouth dimensions  -- by Johan Liljencrants
Pipe cut-up and flue pipe dimensioning chart based upon Ising's formula -- by Johan Liljencrants
Wurlitzer Caliola Organ Pipe Dimensions -- by Julie Porter (070407 MMDigest)

Percussion:
The Construction and Tuning of Vibrating Bars -- by W.E. Flynt
Calculations for Xylophone Bars -- by Jack Breen (980321 MMDigest)
Developing an organ harp -- by Johan Liljencrants
Resonators and Q value -- by Johan Liljencrants
Replacing a Drum Skin -- by Walt Kehoe (060519 MMDigest)

Bellows (Feeder) Pump & Regulator:
Building Organ Bellows, Classical Organ Style & Estey Reed Organ Style -- by Richard Vance
Bellows Pump with Internal Shunt Regulator -- by Hans van Oost
Organ Pressure Regulator and Tremulant -- by Johan Liljencrants
Pushing and Bouncing Air - Some reflections on the Theory and Practice of Pipe Organ Wind Supply -- by Johan Liljencrants

Valves & Pneumatics & Pneumatic Controls:
How to Fold the Cloth in a Pneumatic -- by Troy Taylor (081021 MMDigest)
Pneumatic Pouch Forces - A Designer's Aid -- by Johan Liljencrants
Pouch Operated Valves -- by Johan Liljencrants
Damper for Harp or Chrysoglott -- drawing by Richard Vance (MMD 020108)
Magnet Valves for player pianos and organs
Making Wurlitzer Unit Valves -- by Bob Humes (070217 MMDigest)

MIDI Control:
Octet Design Corporation Products
"MIDI: Musical Instrument Digital Interface" -- by Mike Ames,
    Originally published in Mechanical Music, Vol. 47, No 1, Spring 2001.
MIDI Control for Frati-Hymnia Orchestrion -- by Willy van der Reijden (020312 MMD)
Decap "MidiMapper" Software Program -- contributed by Tony Decap (030331 MMDigest)
Using Cakewalk to Adapt Music for Street Organ -- contributed by Hans van Oost (030419 MMDigest)

Tuning:
"Tuning", by Owen H. Jorgensen -- book review by John Rhodes
Mathematics of Stringing -- by Doug Rhodes (MMD 96.07.03)
Instructions for Tuning Military Band Organs -- courtesy Matthew Caulfield
Sound Speed and Pipe Tuning -- by Johan Liljencrants
Sound Speed and Pipe Tuning -- by Johan Liljencrants [formulae as images]

'Pianolas' & Pianos:
1917 Kimball Player With Pushbutton Controls -- by John A. Tuttle (100212 MMDigest)
Dating French Pianos by Serial Number -- by Jean-Pierre Jouandet (MMD 010201)
Kastner "Kastonome" Accenting Player System -- photos by Iñigo Perez-España, Madrid
Aeolian Themodist Schematic Diagram -- by Richard Vance
Mandolin attachments (for the "honky-tonk" sound) -- by B Bronson
Single-Finger Music Roll Tracking System -- by Julian Dyer
Music Roll Tracking Systems -- by Richard Vance
Aeolian Pianola Player Brake Adjustments -- by Richard Vance (MMD 001002)
Electric Motors for Player Pianos -- compiled by Robbie Rhodes
Hickman Grand Piano Action -- compiled by Robbie Rhodes
Farrand Cecilian Player Action -- by Ed Gaida (020302 MMDigest)
Sloping Bench for Pianola
M. Schulz Co. "Tuner's and Repairman's Manual" -- courtesy Gary Stevenson
Duo-Art Valve Pouches -- by Mark Fudge (030122 MMDigest)
Air-O-Player Tracking Adjuster -- drawing by C. H. Short, August 23, 1917
Volume Indicator for Player Piano-- by John A. Tuttle (040501 MMDigest)

Expression & Reproducing Players

Ampico:
Ampico -- excerpts from the Ampico "Model B" 1929 Service Manual
Spark Chronograph -- by Clarence Hickman, J.A.S.A, Oct. 1929
Spark chronograph, photograph (JPEG 964 kb) -- courtesy John A. Tuttle
Key force recorder, photograph (JPEG 1001 kb) -- courtesy John A. Tuttle

Duo-Art:
Duo-Art Fan Accordion Expression Units -- by Bruce Grimes (040517 MMDigest)
Duo-Art Tubing Diagram, 1925 Steinway Duo-Art Grand Piano -- courtesy Eliyahu Shahar
Duo-Art Piano Concertola Drawings -- by James Heyworth (030621 MMDigest)
Pedal Duo-Art (Half Duo-Art) Tubing Diagram -- drawing courtesy of Alan Turner

Welte-Mignon:
"Welte On/Off" Selector Tubing Diagram -- by Howard Goldberg
Tubing Schematic for Welte-Mignon Licensee -- by John Grant (120707 MMDigest)

Hupfeld DEA:
Hupfeld DEA Reproducing Piano

Nickelodeons & Orchestrions:
Universal Nickelodeon Diagram -- drawn by David McQuaide, forwarded by John A. Tuttle (110218 MMDigest)
Mills Violano-Virtuoso
Tubing Connections for Seeburg Style "L" And Other A-roll Cabinet Pianos -- by Art Reblitz (020318 MMDigest)
Reproduco Piano-Organ (Operators Piano Co.) -- compiled by Robbie Rhodes

Schematic Diagrams & Drawings for Player Pianos & Organs
Wurlitzer 1203 Player Piano Power Problem -- by John A. Tuttle (120108 MMDigest)
PPCo Vacuum Pump Speed Controller Diagram -- by John A. Tuttle
Lauter-Humana Layout Diagram & Poker Tool -- by John A. Tuttle
Aeolian Themodist Schematic Diagram -- by Richard Vance
Mignon 22-note Reed Organette -- by Hans van Oost
Duo-Art Tubing Diagram, 1925 Steinway Duo-Art Grand Piano -- courtesy Eliyahu Shahar
Duo-Art Piano Concertola -- courtesy Jim Heyworth

Music Rolls & Tracker Bar Scales:
1908 Buffalo Convention Piano Roll Specifications -- by Matthew Caulfield (080219 MMDigest)
Bass/Treble Player Piano Split Points -- by Julian Dyer
Identifying music rolls -- "Measure the width of the paper and the distance between the punched holes."  Then check the tables.
"Carl Frei 20er" 20-note crank-organ scale -- by Robbie Rhodes
Cakewalk CAL Template Changes MIDI Note Numbers -- by Tony Decap (001107 MMD)
Piano Roll Graph Paper -- by J. B. Roth
Tracker bar scales -- photos and descriptions
Transcribing music rolls -- Wayne Stahnke's "View" program and sample WEB data files.
Cakewalk CAL Program for WEB Files -- by Walter Tenten (030120 MMDigest)
Wurlitzer APP & Caliola Scale -- compiled by Robbie Rhodes

Music Roll Spool Frames & Readers:
Pratt-Reed Spoolbox & Transmission -- illustration courtesy John A. Tuttle
Spool Frames, Pulleys & Pumps -- Photos and engineering data
Mills AC/DC Rotary Converter -- U.S. Patents
Tracker Bar Select Switch -- by Robbie Rhodes (031227 MMDigest)
Nickelodeon Spool Frame With Belt Drive -- by Ed Gloeggler (040528 MMDigest)

Pneumatic & Optical Roll Readers:
Pneumatic Switch Assembly for Reading Music Rolls-- by Richard Vance
Fiber Optics Reader for Music Rolls -- by Horst Mohr
USB Controller for CIS Optical Roll Reader -- by Julie Porter

Reference data:
Mechanical Forces Developed in Pianola Pneumatic Motors (rumpf_1.doc, 65 kb) -- by Paul Rumpf, November 2008
Mechanical Forces Developed in Pianola Pneumatic Motors (rumpf_1.pdf, 122 kb) -- by Paul Rumpf, November 2008
Forms of Shellac -- by Craig Smith (080306 MMDigest)
Pitch Shift From Change In Loudness -- by Johan Liljencrants (031217 MMDigest)
Wood for Mechanical Music Instruments -- compiled by Hans van Oost
Ozone

Miscellaneous:
Economical Audio Recording -- by Johan Liljencrants (040125 MMDigest)
PDFILE.EXE (217 kb) recovers individual songs from corrupt PianoDisc and Yamaha diskettes -- by Julie Porter (041118 MMDigest)