More calculator updates…

New calculators:

Other notable changes:

  • The Unit Conversion calculator now include electrical units
  • Added to the Constants page.
  • Added formula pages for each calculator (example)
  • Added diagrams to those that need them
  • Updated the jquery mobile library to 1.4.0.
  • Added a revision log
  • Most multi-page calculators were re-written to provide a simpler interface.
  • Some calculators now utilize drop-down menus to specify which variable to calculate for

Coming soon:

  • Parallel Key size and design calculator

If there is a calculator anyone wants to see, let me know. — cheers.

Littlest Track Dog (mark II)

This is the mark II design for the tiny track dog I posted earlier.   This version features a sandwich style construction, which has several benefits over the mark I design.

Littlest Track Dog (mark II)

Securing the aircraft cable through this dog should be vastly easier than the first version.  It’s as simple as two set screws, a few copper inserts, and four flat head machine screws.  Machining the cable path in the first version wasn’t too hard, but cleaning meeting two small, blind holes 135 degrees apart did prove a challenge.  As a result, threading the cable through dog #1 was an exercise in aggravation, something I do not care to repeat.

You’ll notice the top part of the sandwich is steel, which allows us to weld the knife in place through a milled slot.  Since we’re still waiting on details of the tracking furniture, we can build the dog now and leave the knife design for later.  Also, dog #1 featured a removable knife, which is nifty, but seriously impractical at such a small size.

Speaking of size, this dog will be the same as the last one – 15/32″ x 3/4″ x 3 1/2″.

The shop should get one of these built within the next few weeks.  Perhaps I’ll find enough time to slink away from the office and do it myself.  In either case, I’ll post an update, and let you know if all my wishful thinking was for naught.

Stock Power Supplies… Revisited

Months ago I wrote a brief ditty about modifying commonly available computer power supplies to power low voltage DC effects.  You’ll find the original article here.  I wasn’t completely satisfied with the first one I modified.  You can see it in the picture below, it’s the ugly one to the left.  After perusing a Mouser catalogue this summer, I found what I was looking for – barrier strips with pass-thru terminals.  The ones seen below are made by Molex, specifically referred to as Solder Turret Style Terminal Blocks.  Catchy, isn’t it?  The Mouser part number for this specific model is 538-38720-3208.  They come in several different sizes, and I’m sure that other manufacturers make them as well.  Turns out the solder pins are just the right size to snugly fit female insulated spade connectors.  Super convenient, and pretty to boot!



P1020895You need small, ad hoc, weld-on bearings?  Check this out.  Use a plastic bushing, a shaft collar and a cone-point socket set screw.  Weld the shaft collar over a hole, and keep the plastic bushing in place with the set screw (the cone point is key).  Feel free to add a little threadlocker if you’re paranoid.  Works like a charm.


Mechanism Resources

This one’s for the mech heads and purveyors of fine machinery.

Cornell University’s Reuleaux Collection is a collection of 220 machines.  The machines include various crank mechanisms, couplings, linkages, compound gearing… the list goes on.  The website itself is a catalogue of the 19th century machines – some with accompanying videos and technical documentation.  In my opinion, the machines themselves are functional, beautifully crafted works of art; they deserve some attention.

There are also three books that I highly recommend all mech heads have on a shelf somewhere.  Or in the powder room (your choice, no judgement here).

507 Mechanical Movements: Mechanisms and Devices by  Henry T. Brown

  • This slim paperback from 1868 is as simple as it gets: 507 drawings of various mechanisms, and text that describes their operations and uses.

Machine Devices and Components Illustrated Sourcebook by Robert Parmley

  • This bad boy is a compendium of 1,500 different mechanisms.  It’s broken down into assemblies, power transmission, and mechanical components.  A great way to kick start the brain when you need some inspiration.

Mechanisms and Mechanical Devices Sourcebook by Neil Sclater and Nicholas Chironis.

  • This 500 page beast is a good companion to the Machine Devices and Components… title listed above.  I like to think of it as the sequel.

Of course there is Mechanical Design for the Stage by Alan Hendrickson, but I know you already own that one, right?

Note that the book links go to Amazon pages, I’m not saying you should buy from Amazon, in fact I recommend saving a few bucks and getting used copies.