Posts Tagged Sherline
Having used a nail for far too long, this is a definite step up for my machinist vises:
The vise knob has a hole just barely passing a length of 3.4 mm = 9/64 inch mild steel rod from the Small Box o’ Cutoffs.
While I was at it, I made a handle for the parallel jaw clamps:
Those knobs pass a 3.0 mm = 1/8 inch rod, similarly sourced. Inexplicably, one clamp expected no more than a 7/64 inch rod; a brief introduction to Mr Drill Press persuaded it concerning the error of its ways.
I should have made the handles distinctively different, because they’ll get mixed up in the box of vises & clamps. Next time, fer shure!
The Tommy Bar handles use the same solid model as the Sherline Tommy Bars, with hole diameters as noted. Cyan PETG is definitely easier on the eye than red PLA, although it does fade into the background clutter around here.
You’ll recall the LED atop the 21HB5A tube failed, shortly after replacing the bottom LED and rewiring the ersatz plate lead, which led me to rebuild the whole thing with SK6812 RGBW LEDs. So I printed all the plastic parts again, because the duodecar tube socket’s pin circle can fit into a hard drive platter’s unmodified 25 mm hole, then drilled another platter to suit:
The hole under the drill fits the 3.5 mm stereo socket for the ersatz plate lead, so it’s bigger than before.
I’ve switched from Arduino Pro Minis with a separate USB converter to Arduino Nanos with an on-board CH340 USB chip, because the fake FTDI chips on the converters are a continuing aggravation:
Adding those wire slots to the sockets definitely helps tidy things up; the wires no longer need a crude cable tie anchoring them to the socket mounting screws.
I wanted to drive the LEDs from the A7 pin, rather than the A3 pin I’d been using on the Pro Minis, to keep the wires closer together, but it turns out that A6 and A7 can’t become digital output pins. So I used A5, although I may come to regret the backward incompatibility.
In any event, the 21HB5A tube looks spiffy with its new LEDs in full effect:
I dialed the white LED PWM down to 32, making the colors somewhat pastel, rather than washed-out.
The Arduino source code as a GitHub Gist:
A recent OpenSCAD mailing list discussion started with an observation that the dimensions of printed parts were wildly different from the numeric values used in the OpenSCAD program that created the STL. Various folks suggested possible errors, examined the source and STL files to no avail, and were generally baffled.
Finally, a photo conclusively demonstrating the problem arrived:
Note the difference between the digital readout and the analog scale printed on the body.
Turns out it’s his first digital caliper: he simply didn’t realize you must close the jaws and press the ZERO button before making any measurements.
We’ve all been that guy. Right?
FWIW, our Larval Engineer can probably still hear me intoning “Check your zero” every time she picks up a caliper or turns on a multimeter. Perhaps she’ll think fondly of me, some day. [grin]
Having hacked back the end of the USB gooseneck extension, a tweak of the COB LED heatsink mount for my desk lamp produces a smaller version for a 1.8 W LED:
That fits half of a random heatsink, bandsawed just to the far side of the middle fin and milled flat.
Ream out the 5 mm hole with a #8 drill for a snug fit around the gooseneck, jam gooseneck in place, dab epoxy on the corners of the recess, mash the heatsink in place, solder wires to LED, smear epoxy on the aluminum backplate, clamp while curing:
And it looks pretty good, if I do say so myself:
The hook-n-loop tape holding the cable to the bandsaw gotta go, but should suffice until I conjure a better mount.
The alert reader may wonder how a 9 V COB LED runs from a 5 V USB cable with nary a trace of a voltage booster to be seen. Well, that’s not really a USB cable any more; I paralleled the red+white and black+green wires for lower resistance, then hacked a 9 VDC power supply into an old USB hub:
I ripped out the upstream USB plug, hotwired the 9 V supply where the 5 V USB wires used to be, soldered jumpers on the downstream sockets to short the outer two pin pairs together, razor-knifed the power leads going into the epoxy-blobbed USB controller, and declared victory:
Admittedly, that “In Use” LED runs a bit brighter now.
I have a few other tools on that bench in need of LED lights; when I build ’em, they can all plug into this hub. No reason to invent new connectors & cables & all that. It may need a power switch.
Turns your stomach, eh?
The OpenSCAD source code as a GitHub Gist:
For reasons not relevant here, we (temporarily) have a set of pots with glass lids. One of lids had a remarkable amount of crud between the glass and the trim ring under the knob, which turned out to be corrosion falling off the screw. Trying to remove the screw produced the expected result:
For whatever reason, they used an ordinary, not stainless, steel screw:
I figured I could mill the stub flat, drill out the remainder, install a new insert, and be done with it. The knob has a convex surface and, even though this looked stupid, I tried clamping it atop a wood pad:
Two gentle cutter passes convinced me it was, in fact, a lethally stupid setup.
Soooo, I poured some ShapeLock pellets into a defunct (and very small) loaf pan, melted them in near-boiling water, and pressed the knob into the middle, atop some stretchy film to prevent gluing the knob in place:
That’s eyeballometrically level, which is good enough, and the knob sits mechanically locked into the room-temperature plastic slab. Clamping everything down again makes for a much more secure operation:
A few minutes of manual milling exposes the original brass insert molded into the knob, with the steel screw firmly corroded in the middle:
Center-drill, drill small-medium-large, and eventually the entire insert vanishes in a maelstrom of chips and dust:
Run a 10-32 stud into an insert, grab in drill chuck, dab JB Kwik around the knurls, press in place while everything’s still aligned in the Sherline, pause for curing, re-melt the ShapeLock, and the insert looks like it grew there:
Wonder to tell, a 1 inch 10-32 screw fit perfectly through the pot lid into the knob, with a dab of low-strength Loctite securing it. Reassemble everything in reverse order, and it’s all good:
Well, apart from those cracks. I decided I will not borrow trouble from the future: we’ll let those problems surface on their own and, if I’m still in the loop, I can fix them.
The stem fits into a slot made with a 3/8 inch end mill:
You move the cutter by the length of the sensor (10.0 mm will work) to make the slot. In practical terms, drill a hole at the midpoint, insert the cutter, then move ±5.0 mm from the center:
A bead of epoxy around the stem on the bottom of the panel should hold it in place forevermore.
The rectangular inner hole came out a tight push fit for the TCRT5000 sensor, so I didn’t bother gluing it in place and, surprisingly, it survived the day unscathed!
The OpenSCAD source code as a GitHub Gist:
Having accumulated a set of octal tube base clamps, it’s now a matter of selecting the proper clamp for each tube:
The process of shell-drilling the tube base, drilling the hard drive platter, printing a tube socket and case, wiring up the Arduino and base LED, then assembling the whole thing requires a bit of manual labor, assisted by some moderately exotic shop machinery.
The getter flash atop this small 6H6GT dual diode tube rules out a cap and there’s not enough space for a side light:
Fortunately, the base LED completely lights the internal glass:
The slowly changing color would make a fine night light:
It must be Art!