Printing an adapter

2014/10/11

Were making a box for a timed outlet. Had bought mismatched parts. Designed and printed an adapter.

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Making our own toys

2014/10/04

Designing toys ourselves and making them from renewable plastic.

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Aquifer Depletion in California’s Central Valley and Santa Clara Valley

2014/02/23

This is a summary of sources.

More than a century of data in USGS Circular 1182 Land Subsidence in the United States http://pubs.usgs.gov/circ/circ1182/ , specifically:

Those three files contain different information each. They are worth looking at each, all pages, even if you don’t read all details.

About 2013 activity in Stanislaus County, notable articles for numbers mentioned: Read the rest of this entry »


Internal-gear hubs on bicycles

2013/04/16

Before there were derailleurs there were internal-gear hubs. I was brought up appreciating the low maintenance needs of Sturmey-Archer 3 speed hubs. Around 1999 I couldn’t get one where I lived, ended up riding a Shimano Nexus Inter 7-speed. That 7 speed is dead now in 2013, a can of metal shavings, possibly worsened by unwisely riding it under water this winter. This creek hasn’t stopped me yet, but after hydrolocking a truck engine around 2003 it contributed to an early demise of my hub this time around – same creek, different crossing. For me to learn limits.

Now I’m working on replacing the hub with a NuVinci brand continuously variable transmission. Fascinating different mechanical design. I did not see it coming. Reviews by owners seem to be positive. Putting it into my existing bike. We’ll see how that performs, ask a few months from now.

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The duality of a graphics library

2013/02/21

Most any machine one makes or designs one can get so involved in that one is preoccupied with the making or the workings of that machine, one could forget there was a purpose.

Having worked to make Adj viable, in several ways, now this very moment I am not directly facing any of the enterprise software design problems that originally made me want to have Adj. I am sure some will occur sooner or later, complexity is here to stay – just try to understand your CPU chip, all its transistors, how it works, or how it is made.

This made me think though, how do others see Adj? Is Adj

  • something to use, or
  • something to develop?

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A distinctively European drawing board

2012/12/21

Not to be found in America

Probably no gadget fixes big problems. But here is a thought on the topic of kids learning coordinate systems, descriptive geometry, drafting, accuracy, etc.:

In North America in 2012 I couldn’t find the kind of drawing board I had grown up with. An Amazon Germany search for Zeichenplatte A3 shows multiple brand suppliers.

Amazon wasn’t going to ship to the US, and when making arrangements with a relative across the pond, instead of a brand new one we got a decades old heirloom.

drawing board

Heirloom Drawing Board from Germany

Having one is merely one prerequisite for using it. Knowing what to do is the other main ingredient. I used to have fun with those boards. More recently I enjoy seeing kids pick up skills.

I could analyze why this kind of board is better for kids:

  • You can switch the straightedge from horizontal to vertical. That is a biggie, e.g. when drawing front, top, and side views.
  • The built-in paper clamp obviates sticky tape.
  • Plenty of scales.
  • A3 size is perfect. Big enough for detail, small enough for kids, students. Comparable to tabloid size.
  • Ability to lock against sliding.
  • Much drawing can be done without anything sticking out in an inconvenient direction.
  • more

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Weak output from home use 3D printers

2012/06/08

One significant problem with today’s extrusion 3D printers (the kind more people could afford for home, of the order of $2,000) is the output is layered, like a stack of sliced bread, and rather weak in that these slices too easily detach from each other.  Almost all samples I touched broke between layers when applying light pressure with the fingers of one hand.  Sure, you can design with that in mind, but that is a significant restriction.  Wouldn’t want to make an irrigation valve to hold water pressure when you know it has that kind of weakness.

It isn’t surprising, given how the filament of ABS or PLA gets deposited in the XY plane, then after a tiny move upwards on the Z axis another XY plane, at which time the earlier XY plane’s filament has cooled off already.

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