One thing you probably didn’t know about me is that I like to collect beautiful, usually obsolete, scientific instruments. I have a real sextant that I could use to steer a yacht or measure the wobble of earth’s axis, a planimeter (a quite magical device that measures the area of any closed shape) and literally dozens of slide rules. Slide rules were ubiquitous in engineering colleges and in aviation and navigation until quite suddenly the electronic calculator made them obsolete in the 1970s.
When I discovered a planimeter in an aerospace engineering office where I worked in 1980 I was entranced, and spent a lot of the evening of that day scribbling calculus on bits of paper to prove to myself that it worked. I used to get odd looks.
So I have just bought a pantograph. This device was more at home in an artist’s studio, but it embodies some simple geometric rules and it’s quite pretty as well as practical. Here I have photographed it next to two other rare beauties. Neve the greyhound is already quite a familiar sight on this forum. The other beauty is one of my two Keuffel and Esser 4080-3 log log decitrig slide rules along with its scabbard. From the late forties onward this magnificent mahogany rule was one of the finest portable calculating instruments you could own.
The eagle-eyed may spot that the slide rule lacks its essential cursor glass. My other example of this rule is complete.
This 30cm pantograph is used for copying outlines while optionally scaling them up or down. I probably won’t use it for much, but I can pretend it’s for fine work on face panels of my modules or something. And it’s pretty.
lol wasn’t sure at first what you were talking about that was awhile ago . they are a lot bigger now . I don’t know if you would call it " different races " but yeah they are different breads of chickens , though they are all female egg layers .
Part for part this looks exactly like the Meccano Number 4 kit I had in the early sixties. There could be more of this and that, but the parts are the same. Only the different colours mark this kit as being from a different era.
More like daily excavation than daily mail. My goal is to first use up all that electronic junk i hoarded over the years. These are VCA modules from an old Harrison HM4 desk. The TA-101s were all exchanged by someone with poor soldering skills, I hope they still work.
Note: although the scale on the side is labelled “CM” obviously the numbers refer to millimetres. If not the 30 on the left of the scale would mean the device was about 12 inches long.
That’s a really weird marking, it can’t be millimeters either, as the ruler would be only 2cm long (~1")… Maybe they messed up and you should divide by two? 10cm would make more sense…
Or maybe as you draw a circle with that, they multiplied the radius by two to directly read the diameter?
Your final idea is correct. The notches beneath each numeral (which are difficult to see above so here’s a closeup) are 1 centimetre apart, but the numerals go up in 2s.
This side starts at 2cm and refers to the diameter of the circle. The other side (shown in my previous post) starts at 10 and this is because it corresponds to using the circle tool with the moving slide inserted so that the pivot is further away from the Dremel.
Here’s another closeup showing how this is illustrated on the top side of the tool.
A whole heap of five-core flex. This is part of my plan to feed power via good thick flex and aviation connectors instead of ribbon cable. The two extra cores are supposed to provide support for +5V and +3.3V, should I decide I need that. I probably will.
you will have your self some military spec modules , preparing for the apocalypse are you .
no I get it , failing connectors and cables are annoying as hell and sometimes a pain to trouble shoot because they only work when you are looking for the problem .
