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

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
Tour Easy Kickstand Adapter Plate

The venerable Greenfield kickstand on my Tour Easy doesn’t quite match the mounting plate under the frame, with the result that it can pivot just enough to make the bike tippy with a moderate load in the rear panniers. I’ve carried a small block to compensate for sloping ground, but I finally got around to fixing the real problem.

The solution turned out to be a spacer plate that fills the gap between the back of the kickstand casting and the transverse block brazed to the mounting plate:

Tour Easy kickstand adapter plate

That little lip is 2 mm wide, so it’s not off by much.

The aluminum came from a Z-shaped post that contributed its legs to a previous project. I flycut the stub of one leg flush with the surface, then flycut a slot 2 mm from the edge:

Tour Easy kickstand adapter – flycutting recess

For no reason whatsoever, the width of that slot turned out exactly right.

Bandsaw along the left edge of the slot, bandsaw the plate to length, square the sides, break the edges, mark the actual location of the mounting plate hole, drill, and it’s done!

An identical Greenfield kickstand on Mary’s identical (albeit smaller) Tour Easy (the bikes have consecutive serial numbers) fits perfectly, so I think this is a classic case of tolerance mismatch.

2014-08-06
Forester Trailer Hitch: Wiring Installation

Unlike the trailer hitch installation instructions, the wiring installation instructions left a bit to be desired. Basically, you can’t get the trim panels off the interior until you know where they hid the snaps and latches, but you can’t find the snaps and latches before you remove the trim panels.

N.B.: this applies to a 2015 Forester. Subaru deliberately moves the connector around for each model and year, for reasons that certainly make sense to them.

Remove everything from the back end of the car that isn’t firmly affixed.

Remove the rivets from the left-side foam block by prying their heads with a big screwdriver; maybe you can get a needlenose pliers under there. They’re surprisingly difficult to get out, due to that nasty barb on the end:

Forester cargo compartment foam block rivet and socket

Release the left side of the trim strip across the back of the compartment by pulling the front corner forward to unlock the latch that engages the trim panel on the left edge. Then you can pull the strip upward to locate the green rivet about a foot from the left end, stick a screwdriver under there, and pry it out of the frame. I didn’t do that, with the unhappy result that the rivet stayed in the frame:

Forester hatch trim – snap rivet location

If that happens to you, just pry the rivet out of the frame, slide it into the trim strip, and (when the time comes), ram it back into the frame.

A captive plastic cover over the bolt securing the cargo tiedowns yields to a fingernail, if you know that’s what you must do:

Forester cargo tiedown – screw location

Remove the bolt and tiedown, which greatly simplifies pulling the side trim panel away from the frame:

Forester trailer wiring connector location

The trailer hitch connector lies tucked far up inside the recess, taped to the wiring harness with blue tape. Slit the tape, pull the connector free, worm the aftermarket wires up in there, latch the connectors together, and reinstall everything in reverse order.

Subaru could, if they wanted to, add a foot of wire to that harness, tape it near the bottom edge of the trim panel, and eliminate half an hour of dealer labor charge. I think I understand why they don’t do that, but I don’t have to like it.

It’s faintly possible that someone with very thin arms could reach the connector without dismantling the butt end of the car, but the fingers on the end of that arm might not have enough strength to latch the connectors.

The electrical box fit neatly against the rear of the compartment, behind the foam block. A bit of razor knife artistry carved a notch for the fuseholder and the wiring coils up neatly inside an existing recess:

Forest trailer hitch – wiring in cargo compartment

Until I install lighted hitch nuts (you could look it up), I think deploying the trailer connector through the hatch makes more sense than running the wiring through one of the holes in the spare tire well and exposing the connector to the elements. I don’t intend to do much trailer hauling …

2014-07-30