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.

Tag: Improvements

Making the world a better place, one piece at a time

Dis-arming a Steelcase Leap Chair

Steelcase lists the arm rests on their Leap chairs as “factory installed” and not removable, perhaps because the brackets supporting the arms also support the backrest. In the event you must ever remove the arms, perhaps because your wife decides she’d like to try the chair without them, it’s straightforward.

Loosen the Torx screw visible through the slot in the bottom of the plastic shroud about a dozen turns (it will not click or feel loose), use a flat screwdriver to unlock the shroud from the flat plastic plate on the seat side of the bracket, then forcibly pull the sides of the shroud outward until you can pull the arm extension mechanism up-and-out of these slots in the bracket:

Steelcase Leap – arm bracket

This view from the side of the chair shows the screw hole in the bottom, with a pair of holes for alignment pins beside it:

Steelcase Leap – arm bracket

You can remove the flat plate by pushing the latch at the top center (just below the backrest screw boss), then sliding the plate upward.

As nearly as I can tell, there’s no way to remove the shroud from around the arm extension mechanism, so you must pull off the whole thing in one lump:

Steelcase Leap – arm mechanism

The two pairs of slots in the edges of the shroud engage tabs on the plastic plate; that’s why you need the flat screwdriver.

The two pins on the bottom lock the arm into the bracket: you must raise it vertically until those come out, after which you can ease the bottom outward until the pins on the sides (which you can’t see inside the shroud) disengage from the bracket slots.

It takes a whole lot more force than seems necessary, but it can be done.

Wrap Gorilla tape around the raw edges until you decide whether it’s worthwhile to design and print a pair of plastic caps to cover the whole bracket.

2014-09-10
When the Phone Don’t Ring, We Know It’s Carmen
A few weeks ago we ported our landline number to Ooma’s VOIP service, turned on their Community Blacklist, blacklisted a few pests that crept through, and … the scam calls vanished. For the first week, the only calls we received came from people we know.

Most of the Caller ID numbers seem faked, so one side effect of blocking them will be to prevent calls from real persons or businesses eventually assigned those numbers. In particular, I’ve set up a blacklist filter that kills calls from numbers that differ from ours in only the last few digits: at least one scammer combined the first several digits of the called number with some random digits at the end.

Obviously, it’s impossible to kill all the faked numbers. The filters work surprisingly well, though.

Killing nearly all the scam calls is worth ten bucks a month right there, even though it seems odd to pay a private party to prevent illegal action by somebody else. Used to be the government put our tax dollars to work and dealt with people who performed illegal actions, but … that was then, this is now.

As an aside, I wonder how the NSA handles all those scam calls. Given that the Feds regard anybody within three or four hops of a Person Of Interest to be a Person of Interest, not only should all the scammers have terrorist tags (they call everybody all the time, right?), we ordinary folks picking up the phones are now within a few hops of a known terrorist affiliate.

Conversely, if the NSA discards scam calls, then I know precisely how to set up the perfect terrorist communications network.

Verizon refunded $3.11 from our last bill and didn’t try to convince us to retain our landline service. They’d recently “upgraded” our copper line to fiber, so the basement has a nice Optical Network Terminal that I just unplugged; they don’t seem to want it back. Maybe I’ll harvest the 12 V 8 Ah (!) SLA battery for a project.

We’re not interested in the FiOS “Triple Play” special offers that hover around $90/month for two years, plus unknown equipment charges, plus a regional sports network surcharge, plus unknown taxes and fees, with or without a $250 gift card kickback, with or without a discounted tablet. The cable company recently boosted what we pay for 15/3 cable to $60/month, so we’re definitely trapped by a duopoly.

Some things (all, some, or none of which may be true) I learned while chatting with various contestants:
- Overtalking them with “You may hang up at any time if you agree that you’re a scammer” produces either an immediate hangup (they agree!) or a very interesting discussion.
- Starting with “You have sixty seconds to prove you’re not a scammer. Go!” generally produces an immediate hangup.
- Setting up a call center “the size of your garage” costs about 85 kilobucks and provides seats for about a dozen “agents”.
- It’s the best job you’ve had, if you’ve been unemployed for three years, because it’s minimum wage plus a bonus for every prospect you “qualify”, all without having to work in a retail environment. I was unable to discover when the bonus kicks in, but likely after the Level 2 closer sucks actual money out of the victim’s credit card account.
- Some contestants sincerely believe they’re doing a Good Thing: helping people get lower interest rates on their credit card debt. Pointing out that I’ve asked my credit card issuer whether that works and getting a firm “No!” in reply doesn’t change their belief in the least.
It’s sad that getting a dead-end job in a scamming company might be the best thing that’s happened to some of those folks in a long time. Makes me almost regret having some of them break down and cry under interrogation…
2014-09-09
Revlon Tweezers: Bad Spot Welds
Mary bought a pair of Revlon tweezers a while ago, picking a Name Brand to avoid hassles with bottom-dollar crap:

Revlon tweezers – bad spot welds

Well, that didn’t work.

I contend that the only difference between Name Brands and the bottom-dollar crap I tend to buy is a bit of QC and a lot of price. I’ll agree that’s not strictly true, but it does fit a goodly chunk of the observed data.

Anyhow.

I milled a recess into the corner of some scrap plastic to locate the handle end, then arranged a step block to capture the business end:

Revlon tweezers – drilling setup

That setup ensures the holes go into the corresponding spots on both pieces, because I couldn’t figure out how to clamp them together and drill them both at once. I drilled the other piece with its good side up to align the holes; doing it bad side up would offset the holes if they’re not exactly along the center line.

A closer look:

Revlon tweezers – drilling fixture

Talk about a precarious grip on the workpiece!

I filed the welds flat before drilling, so the pieces lay flat and didn’t distract the drill.

Then:
- Center-drill
- Drill 2-56 clearance
- Scuff up mating surfaces with coarse sandpaper
- Apply epoxy
- Insert screws
- Add Loctite
- Tighten nuts to a snug fit
- Align jaws
- Tighten nuts
- Fine-tune jaw alignment
- Apply mild clamping force to hold jaws together
- Wait overnight
- Saw screws and file flush
- Done!
The clamping step:

Revlon tweezers – epoxy curing

Those nicely aligned and ground-to-fit jaws were the reason Mary bought this thing in the first place.

The screw heads look OK, in a techie sort of way:

Revlon tweezers – fixed – front

The backside won’t win any awards:

Revlon tweezers – fixed – rear

But it won’t come apart ever again!

There’s surely a Revlon warranty covering manufacturing defects, printed on the long-discarded packaging, that requires mailing the parts with the original receipt back to some random address at our own expense.

Ptui!
2014-08-28
Booklet Printing
Most technical papers intended for publication in Refereed Journals have huge margins. When I print them up as pamphlets for E-Z reading in the Comfy Chair, the text becomes an unreadably small block in the middle of the page.

Having tried various simple hacks that don’t work, the best solution so far involves a bit of PostScript magic…
```
pdfcrop --margins 36 whatever.pdf
pdftops -level3 -origpagesizes whatever-crop.pdf
ps2book.pl -f 1 whatever-crop.ps
ps2pdf whatever-crop_book.ps
```
Which will emit whatever-crop_book.pdf. Print the odd pages, reinsert the stack, print the even pages, then either fold or slice/bind as appropriate.

The --margins 36 puts a little whitespace around the text, which may be needed to get the text block out of the gutter if you’re binding the booklet. For those documents, --margins "36 0 18 0" may be more useful; note the blanks, not commas. This requires tuning for best picture, depending on the incoming PDF layout.

The -origpagesizes prevents the next step from assuming an incorrect page size. This is definitely necessary, at least in my experience so far.

The -f 1 enlarges the source text to fill the output page, which is the key step making the whole thing work for small incoming page sizes. However, there’s a weird interaction between this and the pdfcrop margins that I haven’t figured out yet; a zero-width incoming margin [may | may not] jam some line ends against the right edge of the output sheet.

That’s all derived from some booklet-printing hints in the Scribus wiki. A working link (as of today, anyhow) for the ps2book.pl script:

http://www.capca.ucalgary.ca/wdobler/utils/ps2book.xhtml

The R380 emits pages bassackwards for reading, but in the proper order for duplexing: the blank side of the first sheet is on the bottom of the stack, so it becomes the top of the flipped stack, ready to go back into the printer as the first sheet again.

Conversely, the HPLJ1200 produces output in normal reading order, with the blank side of the last sheet on top of the stack: flip and print the back sides in reverse order.
2014-08-27
Trimming Ironman Sunglasses

These sunglasses fit Mary’s face and do a good job of keeping road grit out of her eyes, but she doesn’t like the extended earpieces. So I cut ’em off:

Ironman sunglasses – trimmed earpieces

The trick is to shape the ends with an ordinary diagonal cutter, then round the edges with sandpaper.

The lower pair has seen a few years of use, during which the bright yellow plastic faded quite a bit.

Nothing profound, other than that you need not put up with nuisances.

2014-08-24
Bike Helmet Boom Mic: Assembly

After building the mic mount, another dab of epoxy mounted the length of AWG 10 wire I said I wouldn’t use:

Bike Helmet Mic Boom – rod epoxy

The whole point of the complex mount is to expose the two noise cancelling holes on the back of the electret element:

Bike Helmet Mic – electret element rear

Add heatstink tubing over the entire length of the boom wire, use more black cable ties, shape another foam ball:

Bike Helmet Mic Boom – installed

And it worked on the first try, not that there’s much to it.

Yeah, that’s the HDR-AS30V camera mount up top: dork mode in full effect.

2014-08-13
Bathroom Sink Drain Pop-Up: The Rot Continues

Once again, the black bathroom sink drain stopper stopped popping up. Having had this happen once before, I knew what I would find:

Corroded bathroom sink drain lever

The lever arm to the left of the ball should be about twice that long, minus the jagged end.

I slid the ball rightward to expose more rod, introduced both ends to Mr. Bench Grinder to round them off, scuffed up the short end with sandpaper to improve its griptivity, then slobbered on enough JB KwikWeld to cover the entire length of rod that will live inside the drain:

Epoxy-coated bathroom sink drain lever

The first failure took 9 years, this one took 4…

Memo to Self: Next time, replace the rod with something that doesn’t corrode.

2014-08-12