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Ed Nisley's Blog: Shop notes, electronics, firmware, machinery, 3D printing, laser cuttery, and curiosities. Contents: 100% human thinking, 0% AI slop.

Tag: Mini-lathe

Tweaking an LMS 5200 Mini-Lathe

Vacuum Tube LEDs: Brass Ersatz Heatsink

A chunk of 1/2 inch = 12.7 mm brass hex rod looks pretty good as an ersatz heatsink serving as an ersatz plate cap on a halogen bulb standing in for a vacuum tube:

Halogen bulb brass cap – overview

The knockoff Neopixels measure just over 10 mm at their widest points, but some judicious filing rounded it off and brought it down to fit in the 3/8 inch = 0.375 = 9.52 mm hole I drilled in the hex:

Halogen bulb brass cap – wiring

I let it run for a day like that to make sure the thing wasn’t going to crap out, then epoxied everything in place. If the WS2812B controller fails, the repair will require drilling out all the electronics and wiring, then rebuilding it in place.

The fins come from the same HSS cutoff tool I used for the Bowl o’ Fire cap, cut at 2.5 mm intervals to produce 0.9 mm fins that IMO better suit the smaller diameter. I stopped cutting when the tool got through the hex flats to produce a continuous ring, cut the hex off a bit above the top fin, rounded the end with a carbide insert cutting tool, then sanded the flats to shine ’em up a bit:

Halogen bulb brass cap – detail flash

It turns out that 12 inches of wire inside PET braid barely reaches from the cap to the Arduino Pro Mini in the base:

Halogen bulb brass cap – Arduino Pro Mini

Next time, I’m going to add half a foot more wire than I think it can possibly require, with PET braid to suit.

A thin ring of clear epoxy holds the “heatsink” at the dead center of the bulb. It lights up a bit more than I expected, so opaque epoxy may be in order:

Halogen bulb brass cap – detail red

It’s still too big to suit even the big 21HB5A tubes, but brass definitely wins over plastic!

That blue PETG base has become the least-attractive part of the lamp, but it’s survivable for now.

It runs the same TubeMood firmware as the Bowl o’ Fire.

2016-08-02
Vacuum Tube LEDs: Bowl of Fire Floodlight

Although I didn’t plan it like this, the shape of the first doodad on the mini-lathe reminded me that I really wanted something more presentable than the (now failed) ersatz Neopixel inside the ersatz heatsink atop that big incandescent bulb.

So, drill a hole in the side:

Ersatz aluminum heatsink – drilling

Epoxy a snippet of brass tubing from the Bottomless Bag o’ Cutoffs into the hole:

Ersatz aluminum heatsink – tubing trial fit

Recycle the old wire and PET loom, solder to another fake Neopixel, blob epoxy inside to anchor everything, and press it into place:

Ersatz aluminum heatsink – epoxying LED

Cutting the failed LED & plastic heatsink off the wire left it a bit too short for that tall bulb, but some rummaging in the heap produced a 100 W incandescent floodlight with a nicely pebbled lens:

Reflector floodlight – overview

A thin ring of clear epoxy secures the ersatz heatsink to the floodlight:

Reflector floodlight – finned LED holder

This time, I paid more attention to centering it atop the General Electric logo ring in the middle of the lens, which you can just barely see around the perimeter of the aluminum fin. By pure raw good fortune, the cable ended up pointed in the general direction of the socket’s pull-chain ferrule; you can’t unscrew the bulb without tediously unsoldering the wires from connector atop the knockoff Pro Mini inside the base and squeezing them back out through the ferrule.

With the firmware set for a single fake Neopixel on pin A3 and a 75 ms update rate, the floodlight bowl fills with color:

Reflector floodlight – purple phase

It puts a colored ring on the ceiling and lights the whole room far more than you’d expect from 200 mW of RGB LEDs.

Pretty slick, even if I do say so myself …

2016-07-27
Mini-Lathe: First Cuts

Despite the craptastic way finishing and the cross slide DRO malfeature, the Little Machine Shop 5200 lathe works well enough for my simple needs. I really like the quick change toolpost:

LMS Mini-lathe – first cuts

The QC post and tool holders have very nice machining and surface finish; they evidently come from an entirely different production line than the lathe components. I can definitely get used to using carbide inserts, although I ordered some HSS inserts for interrupted cuts.

The HSS cutoff tool does what you’d expect:

LMS Mini-lathe – first cut – drilled and slotted

The holes in the end came from short (“screw machine”) drill bits I got for the Sherline’s painfully limited Z axis travel. Even so, chucking one in the 1/2 inch capacity LMS drill chuck shows why a 16 inch bed isn’t excessive:

LMS Mini-lathe – drill chuck vs bed length

The 6 inch = 150 mm scale on the bed (to the right of the tailstock) extends to the limit of tailstock travel, so you could have another half foot of stock sticking out of the 3 jaw chuck. A collet in the spindle would give you another two inches, but it’s snug in there.

On the other paw, this is a little lathe intended to make little things. It’ll do fine…

2016-07-26
Mini-Lathe: Control Box Cover Screws

It’s easier to remove the leadscrew while dismantling the carriage and apron, which requires removing the cover from the control box containing all the switches & knobs. Come to find out the “cover” actually holds all the gadgetry onto the headstock:

LMS mini-lathe – control box interior

I want to replace the Power indicator with something visible in normal shop light; judging from the connectors and overall brightness, it’s a neon bulb inside a green housing.

Anyhow, the four screws holding cover to the headstock weren’t identical:

LMS Mini-lathe – cover screws

I thought the oddball screw was deliberate, perhaps fastening that corner to a plastic frame of some sort, but it turned out to be a quick fix for a boogered tap job:

LMS Mini-lathe – mistapped cover hole

A bag of 4 mm knurled brass inserts will arrive in a while, after which I’ll drill out all four holes and epoxy inserts in their place. Might have to use stainless hardware, just for nice…

2016-07-25
Mini-Lathe: De-oiling the Chuck

The mini-lathe arrives covered in oil and the chuck is no exception. Wrap it in a paper towel, spin it up, let it sling out (nearly all) of the excess oil:

LMS mini-lathe – chuck de-oiling

Unwrap, enjoy…

2016-07-22
Mini-Lathe: Carriage Stop Improvements

I got an LMS adjustable carriage stop along with the mini-lathe to simplify cutting things to length. A few tweaks make it much less annoying to use:

LMS Mini-lathe – carriage stop – crude shim

The fluorescent red tape makes the handle stand out vividly against the general clutter. It lives in the shadow of the chuck, where an extended jaw could end its life, so some protective coloration seemed in order.

The screw threaded into the lower part holds it together, but, as with the carriage retaining plates, only the outer edge clamped onto the lower part of the bed. Three layers of credit card plastic fill the gap and allow just enough compression to go from “freely sliding” to “firmly clamped” in half a turn of the lever.

The washer lets the lever turn easily on the upper block.

Remove the screw and spring from the lever to lift and properly re-index it on the internal nut.

The spring on the adjusting screw seems too long and exceedingly stiff for the task at hand. The Big Box o’ Little Springs didn’t offer a suitable replacement, so adapting / making one goes on the to-do list.

It really needs a sliding pin just to the left of the lever screw to hold the lower block in alignment, but that’s definitely in the nature of fine tuning.

2016-07-21
Mini-Lathe: Apron Shim

Eks gave the traverse crank a few twirls, told me the gear was engaging the rack entirely too tightly, and recommended shimming the apron:

LMS mini-lathe – apron shim

Of course, he was right.

Took two 18 mil shims to make it feel right, for whatever that’s worth.

That isn’t the prettiest solution, but it’ll suffice until the ways wear a bit more, things settle in, and I can cut a proper shim to surround the bolt holes across the entire bearing surface.

You can just make out the transparent plastic sheet that serves as a chip shield around the traverse gear shaft; kudos to LMS for that upgrade.

A chip shield tube / roof over the leadscrew is in order, too.

2016-07-20