The Smell of Molten Projects in the Morning
Ed Nisley's Blog: Shop notes, electronics, firmware, machinery, 3D printing, laser cuttery, and curiosities. Contents: 100% human thinking, 0% AI slop.
Mechanical widgetry
Spotted this at an Ohio rest area along I-90:
The slanted stake isn’t a normal vector for the sign surface, but you could derive one…
For whatever it’s worth, Ohio wins the Interstate Highway paving quality award, hands-down, in comparison with New York.
Mounting a circuit board atop the Victoreen 710-104 ionization chamber requires figuring out the location of those 6-32 studs:
Given that it dates back to the early Cold War days, the bolt circle dimensions are all hard inch:
I embossed the studs into a pad of Geek Scratch Paper, eyeballed the stud-to-stud spacing from a cheap ruler, back-calculated the BCD, rounded it from 2.742 to the obvious 2.75, then fed that into the first BCD calculator that appeared in the obvious search.
The can is just over 3.5 inch OD and stands 1.5 inch tall.
The can will run at +24 V in relation to the rest of the circuitry, so the studs must be insulated from the PCB’s copper pours. That, most likely, will require some 3D printed doodads.
The circuitry must live inside a grounded metallic can that excludes random electric fields. Somewhere in the pile, I have a few sheets of Mu-metal that, while grossly overqualified for the task (even without heat treatment), should solder up nicely…
An embossed sheet of my Geek Scratch Paper carried the valve knob sizes home from the garden, which prompted a comment from Mike about The Good Old Days in sunny California. Because I’ve disabled comments on old posts due to the spam load, here it is:
Ed has made references to his “geek scratch paper”… which brought back memories.
Gullivers Restaurant in Orange county, CA has been around since at least 1974. Back then they catered to the moderately expensive out-for-dinner crowd in the evenings and on the weekends, but during lunchtime they had a businessmans luncheon special in the main dining room that was oriented towards a decent meal and in-and-out-in-an-hour. The side rooms were for those that were doing longer lunches or business deals over lunch.
The key was that Gullivers was smack dab in the middle of Orange County’s tech region and right across the street from the large airport (now called John Wayne Airport). It’s also very close to Interstate 5, Interstate 405, and state highway 55… all 4-lane-each-direction major freeways.
During those lunch hours it was not unusual to see ID badges from over 20 companies in the main dining room. Several new products and at least one new company were formed over those lunches.
But the topic was “geek scratch paper”… well… Gullivers lunchtime paper placemats back in the 1970s were printed with graph paper on the back side!!!
Imagine: Geek scratch paper at every table provided by a thoughtful restaurant!!! And this was forty years ago!!!
I worked at one of the design houses in the area for over two years. I personally know of at least four new circuit designs, a half dozen new sheet metal designs, a number of circuit board re-designs, several new or modified software routines and at least six Product Change Notices and Engineering Change Orders that were started on the back of a Gullivers place mat (or three, or four…).
For a long time my resume had a bullet point that read “Able to convert lunchtime scratch paper engineering sketches into formal documentation and engineering change orders”.
I’ve not been inside Gullivers since 1981 – in over thirty years I’ve not been in that area except to drive on Interstate 5 on the way from Los Angeles to San Diego. The restaurant may be gone or remade itself into something else. But the next time I’m in that part of southern California I’ll make a special stop and check, and if their placemats still have graph paper on the back side, I’ll email you a photo or three.
On a different but similar topic… At one time the local ham radio club members used to choose which restaurant to migrate to after the monthly meetings by which ones had a blank back side on the place mats…. especially for the planning sessions prior to major events.
Mike WA6ILQ
Armed with bags of electronic parts and boxes of meters, I’ll be helping folks at the CNC Workshop understand the electrical limitations of the Arduino microcontrollers they’re building into projects.
The presentation in PDF form:
Arduino Survival Guide – Workshop Edition – CNC Workshop 2015
We’ll wing it with the source code, because nothing’s more than a few lines long…
This afternoon at the CNC Workshop, I’ll be bootstrapping folks into creating 3D-printable solid models with Openscad.
The presentation in PDF form:
Practical Solid Modeling for 3D Printing with OpenSCAD – CNC Workshop 2015
The OpenSCAD source code for the exercises, in case you don’t want to type along:
Practical Solid Modeling for 3D Printing with OpenSCAD – Models.zip.odt
When you download that file, you’ll get something ending in .zip.odt. Rename it to remove the .odt extension, because it’s really a ZIP file; WordPress doesn’t allow users to uploads ZIP files.
If all has gone according to plan, I’m in Detroit today and will give a talk at the CNC Workshop on (my view of) the status of personal 3D printing, what to expect in the future, and what you can do with it today.
The presentation in PDF form: 3D Printing Status 2105-06 – CNC Workshop Detroit
Our Larval Engineer stopped by, on her way to a half-year co-op job out around Route 128, and devoted a few days to merge-sorting / triaging her possessions. Having shown her the HP 74754A plotter project, she later dropped a bag o’ stuff on my desk without comment:
The perforated pen holder stuck to the plotter case (hey, it would still fit!) in front of the carousel with a bit of foam tape on an angled bracket you can’t quite see. It held 15 pens at the ready: I really used that plotter.
The doodle on the yellow sheet sketches a bulky adapter between the spindle nose thread on the Sherline CNC mill and a plotter cartridge. The flange-less pen body might just fit into the spindle bore, but I remember concluding that machining pen bodies or adapters wasn’t worth the effort. Now it’s a simple matter of some OpenSCAD source code and a few hours of hands-off production, so perhaps I should re-think that.
No dates on anything, but I got the Sherline in 2004. The pen holder probably dates back to the late 80s, shortly after I got the plotter. Most likely, I gave her the bag o’ stuff and told her to make something interesting; it could still happen…
The Smell of Molten Projects in the Morning 