Bob Essex MIDster Punch
by Craig Johnson

cjohnsonPunch1.jpg (19 kb)


I have been interested in mechanical instruments ever since my parents took me to "Al Svoboda's Nickelodeon Tavern" in Chicago Heights over 30 years ago.  The experience of hearing those wonderful instruments made an indelible impression on my young mind.  Now, 30 years later, I am trying to share that experience with my own two sons.  My wife and I own a player piano and a small roll collection.  I have just completed the Bob Essex punch machine and I am set to begin construction of a small Dutch street organ.

Building the punch machine has been very satisfying.  The instruction booklet is exceptional: it covers all aspects of construction and operation.  The booklet, as Mr. Essex explains in the introduction, is not a specific set of plans; the final configuration of the machine is left up to you.  Images of the prototype can be found on the MIDster Punch web site, http://members.aol.com/MIDPUNCH/index.htm .

My version is made largely of cast aluminum plate.  It is driven by two 50 oz/in stepper motors.  The punch traverse motor is coupled directly to a 5 turns-per-inch anti-backlash ball screw.  This yields .001-inch resolution.  The paper advance roller is driven through a 5:1 timing belt.  I have temporarily mounted a solenoid in the punch frame.  I will change this to an air cylinder to punch thick book stock.

The section of the booklet describing the electronics is very clear and specific.  My only change in the electronics has been to use a pair of stepper motor driver cards I had left over from another project.  The electronics as designed are optically isolated from the PC.  This is a very good protective feature.

The software is easy to use and very adaptable.  It is hard to imagine a format it could not be configured to punch.  Mr. Essex has been very helpful in responding to questions regarding a glitch I was experiencing.  (My hardware was at fault).  Included with the software are a number of sample tunes as well as alignment aids.

If you have had some experience with electronics and have access to modest shop facilities, I am certain you can build a very useful machine.

Next I will begin a keyless version of the Johan de Vries street organ ( http://www.psy.vu.nl/homes/johan/orgels/draaiorgel/kistdraaiorgel.uk.html ).  I will let everyone know how it turns out.

Sincerely,

Craig Johnson
Orland Park, Illinois
Tue, 25 Jul 2000 08:04:49 -0500


25 July 2000