Ed Nisley's Blog: Shop notes, electronics, firmware, machinery, 3D printing, laser cuttery, and curiosities. Contents: 100% human thinking, 0% AI slop.
While walking home with the bike, I noticed that the odometer wasn’t matching up with reality. This generally means the front-wheel magnet sensor got whacked out of line and, given that I’d just laid the bike down on that side, that’s what I expected to fix.
As it turned out, the failure meant it was time for the more-or-less annual contact cleaning. The three tiny contact balls on the bottom of the Cateye Astrale tend to collect enough dirt over the course of a few thousand miles to become intermittent. The balls lead to the wheel and pedal sensors, with a single common wire.
Cateye Astrale contacts
You can see that they’re not shiny little factory-fresh bumps. Here’s a detail of the upper-right one on the base to the right. Even through the horrors of a tight crop from a hand-held shot, you can see the problem.
Cateye Astrale – contact detail
No big deal, just wipe ’em off and apply a bit of DeoxIT to make ’em happy again for another year.
On my way back from a ride around the block the back tire went pfft thump thump thump. I’m 1.5 miles from home: fix or walk?
The first step: always examine the tire to find the puncture, before you move too far. Finding something sticking out of the tire means you’re well on your way to fixing the flat. Lose the entry point and you’re left to blow up the tire and listen for escaping wind. So I picked up the butt end of the bike, spun the wheel, and this little gem heaved into view…
That area of the road has seen several collisions in recent months that left the shoulder littered with broken automotive glass. The shard in my tire glistened like a diamond, because one side was flat and mirrored; perhaps it’s from a headlamp reflector or side mirror. The pointy end went into the tire, of course…
Glass fragment and puncture
Well, a single-point failure like that is easy to fix, so:
remember that the hole is a few inches spinward of the label
shift to small chainring / small sprocket
get the tool bag out
lay the bike down (it’s a recumbent, this is no big deal)
release the rear brake
release the skewer and whack the hub out of the dropouts
apply tire irons to get the tire off
pop the tube out and examine the innards
No pix of any of that, but suffice it to say I was astonished to discover that the glass penetrated the Marathon tire’s Kevlar belt just barely far enough to poke the Slime tire liner, but not enough to leave more than a hint of a mark on the tube. Definitely not a puncture and certainly nothing that would account for a sudden flat.
That glass shard is not why the tire went flat! Tire liners FTW!
Examining the rest of the tube revealed this situation a few inches anti-spinward of the glass fragment.
Failed tube rubber
There’s a row of holes across the tube, with no corresponding tire or liner damage at all. As nearly as I can tell, the tube rubber simply pulled apart across that line, all at once, and the air went pfft just like you’d expect.
That’s not survivable, but I don’t carry a spare tube (well, two spare tubes: 700x35C rear and 20×1.25 front) on rides around the block. Long bike tours? Yup, spare tires & tubes because I’m that type of guy.
Anyway, I’ve got the tube in hand, so what’s to lose? Scuff it up with the sandpaper and yipes…
Tube after scuffing
What’s not obvious in the picture is that all those little spots around the big holes are pinholes. The whole area of the tube must have gotten just barely enough rubber to cover the mold.
I know as well as you do this isn’t going to have a happy outcome, but I slobber on the cement, let it dry, squash on a big patch, install the tube & tire, fire a 16-gram CO2 cartridge into it, and … it doesn’t seal.
The tube is several-many years old, probably from whoever was supplying Nashbar at the time, and it served well, so it gets a pass. I’d rather tubes fail in the garage than on the road and sometimes they do, but that’s not the usual outcome.
My ladies were out gardening at the time and a long wheelbase ‘bent isn’t the sort of thing you can stuff into a friend’s car. Not to mention that my ladies had the magic phone.
So I walked home.
Sometimes a man’s gotta do what a man’s gotta do.
Memo to Self: Schwalbe tube at 8910. Reversed(*) the Marathon’s direction.
(*)They’re directional, but when they get about halfway worn I don’t see that it makes much difference. The rear tire on my bikes wears asymmetrically: probably too many tools in the left underseat bag.
When I replaced the kitchen counter & installed a new sink, I added a soap dispenser, mostly because the stainless steel sink had three holes that needed filling. After nigh onto a decade, the dispenser pump is now getting sticky: difficult to push down and reluctant to pop up.
Soap dispenser pump
The problem seemed to be that the O-ring wasn’t sliding nicely along the internal bore.
The catch is that both ends have ball check valves, so you can’t just squirt lube into the bore. I tried prying the thing apart, but the snap-together cap has a really aggressive closure.
So I shoved the exit valve ball (on the left of the picture) out of the way with a pin punch, wedged it into the end of the spring, and squirted the least amount of silicone lube I could manage into the pump. A bit of fiddling un-wedged the ball and got it back in position.
The pump works fine now, but I have my doubts as to how long the lube will last with continuous exposure to soap and constant sliding.
The thing probably needs a new O-ring and I’m certain of two facts:
My shop assistant came home with a five-dollar tag sale find: either a genuine antique car horn or a reasonable facsimile lashed together by an underemployed Pakistani shipbreaker. The original rubber bulb had long since rotted away, but the brass reed worked fine and the horn gave off a mighty honk! when given sufficient wind.
She bought a replacement bulb with hardware definitely made by the shipbreakers, knowing full well that the internal thread on the end of the new bulb’s brass stem couldn’t possibly match up with the external thread on the old horn. We sketched out some possibilities and decided to make a bushing over the horn’s stem with an internal thread: easier than a very short, perilously thin, double-threaded adapter ring.
She measured various dimensions of both pieces and we consulted Machinery’s Handbook. The horn has a really crusty 32-tpi thread somewhere between 1/2 and 9/16 inch, which is not standard at all. Heck, it’s not even metric. (#include standard-metric-goodness-rant)
Horn fitting
The fitting also has an internal pipe thread (!) for the brass reed assembly. We eventually filed a few bits off the reed’s mounting dingus in order to clear the final bushing ID.
Some poking forced the scrap pile to disgorge an aluminum cylinder of exactly the right size for the bushing, with a nice half-inch hole right down the middle. Using a half-inch bolt with a center-drilled end as a mandrel, we brass-hammered it to line up pretty true, and she cleaned off the OD while learning about the quick-change gearbox; a round-nose bit at 104 tpi puts a nice zeepy (her term) finish on aluminum.
We left it stout, rather than trying to turn it down to a thin and elegant shell, because that was the easiest way to get things done. She’ll epoxy it to the horn stem and apply some Loctite to the horn bushing.
A lot of rummaging in the tool cabinet’s recesses produced a taper-shank drill slightly larger than the bulb stem. She drilled out most of the cylinder’s guts, leaving just enough for the threads at the far end, counting 1/10-inch turns on the tailstock all the way.
Shop Assistant Making Swarf
That pile of razor-edged swarf is now prized possession…
She bored out the narrow end to what seemed like the right minor diameter, given that we really didn’t have anything more than a guesstimate of the thread dimensions. I figured we could just continue threading, eating away at the ID, until it fit.
I don’t do a lot of internal threading, but we found a suitable threading tool, lined things up, and she learned about single-point threading by cutting a thread to match that horn. No measurements worth mentioning; this wasn’t the sort of job requiring a Go-NoGo gage.
I stayed away while she completed the threading, apart from consoling her when she discovered why you shouldn’t hand-rotate the chuck with the quick-change gearbox disconnected. We picked up the thread again and she completed the mission.
Here’s the raw thread before beveling the entrance.
Horn Bushing
And then it fit! Verily, the horn itself was the Go-NoGo gage.
Horn in bushing
This was the second part she’s turned on the lathe; I’d say she’s doing just fine.
Our ancient Sears Kenmore electric clothes dryer (which is not matched to the never-sufficiently-to-be-damned HE3 washer) started squeaking again. The last time it did that, I tore it apart and determined that the rear seal between the drum and the back panel needed replacing; I ordered the seal, buttoned up the dryer, and, amazingly, the squeak Went Away.
The box with the new seal arrived a few days later and has been perched atop the dryer for the last few months. Never borrow trouble, sez I.
Unlike the HE3 washer, tearing the dryer down isn’t a big deal. Two screws secure the lint trap enclosure to the top panel; be careful about not dropping them down the chute.
Screws holding lint trap to top
Then push the top forward and pry it off the clips holding it in place. You do not need to remove what looks like clips holding the top to the back panel; they’re sort of hinges that let you tilt the top back. With any luck, you can let the top hang; I rested it on the nearby laundry sink.
Door switch
Two screws hold the entire front door panel in place. Before you remove those, disconnect wires from the door latch switch so you can remove the front panel. The alert reader will note I didn’t do that…
The drum has two sliding seals that bear on the front and rear panels. There is nothing else holding the drum in place, so when you remove the front panel, the drum falls out. It’s helpful to have an assistant holding the drum in place, perhaps with a hand through the open door, while you jockey the front panel out of the way.
Drum belt path through tensioner
Have your assistant continue to hold the drum while you memorize the path of the drive belt around the tensioner and motor pulleys. This is not obvious: you don’t have to take the tensioner pulley off the shaft to remove or install the belt.
There are two sets of slots in the dryer base plate that could hold the tensioner. Only one set will work. Pay attention to the situation in your dryer.
Hint: the drum rotates counterclockwise as you view the front of the dryer. The motor pulls the belt off the drum and the tensioner acts on the slack side of the belt. If you try rotating the drum clockwise, the tensioner and motor make graunching noises that will convince you something has gone terribly wrong. It hasn’t, you’re just turning the drum the wrong way.
With the drum out, this is what the old seal looked like:
Worn seal
I cut the threads at the seam holding the ends of the old seal together and peeled it off the drum. That reveals the dried adhesive all around the drum.
Removing old seal
I applied xylene to soften the adhesive, then used a razor knife and a vast quantity of rags to remove the goo. The key is to get enough xylene on the adhesive to get its attention without slobbering solvent all over the drum; it will soften the paint, which is a Bad Thing. Do this in the garage or outdoors to enhance Family Harmony.
I did a trial fit of the new seal, which showed it’s a snug fit and requires careful alignment. A dozen small clamps held successive parts in place while I got it settled. The trick is to position the center part of the T-shaped seal against the rim of the drum without wrinkles. You probably can’t get it right without a dozen clamps.
To apply the adhesive, I removed two clamps, eased that section of the seal off the rim, and ran two beads of adhesive: one along the rim where the previous adhesive had been and a smaller bead just below the folded metal edge. That pretty well smeared out as I eased the section back in place.
Then remove the next clamp, ease that section off the rim, apply adhesive, and iterate all the way around.
Clamping new seal to drum
I dug a patched bicycle tube out of the drawer and eased it under the clamps around the drum, then pulled it mildly taut all the way around to apply uniform pressure to the seal. Two larger clamps held the slack ends in place.
After supper, we declared the adhesive (which looks & smells a lot like plain old contact cement) to be cured. Off came the clamps and tube and, lo and behold, it’s all good.
Reassembly is in the obvious reverse order. The instructions packed with the seal remind you to ease the loose end of the seal outside the drum where it can ride on the back panel. Make it so.
While your assistant holds the drum in place, reinstall the tensioner and route the belt around it. The belt in our dryer has two possible positions on the pulley (it has ridges), so I made sure it was tracking in the same position as before.
Attach the front panel, rotate the drum a few times to be sure everything is in place and tracking correctly, then slam the top, screw it down, and you’re done!
Alas, the mirror I installed this spring didn’t survive our bicycling vacation; it succumbed to the second of three stuff-all-the-bikes-in-a-truck schleps arranged by the tour organizers. Being that sort of bear, I had a spare mirror, duct-taped it in place, lashed it down with some cable ties, and we completed the mission.
So.
Back to the Basement Laboratory Plastic Repair Wing.
The strut broke just behind the ball at the mirror, which implies the mirror plate got stuffed against something, rather bending the strut. The ball joint still worked, so I maneuvered the stub perpendicular to the mirror.
Drilling the strut
Normally I’d try to re-glue the joint as-is to get the best fit, but past experience shows that if it breaks once, it’ll break there again. I wanted to put some reinforcement into the strut, not just depend on a solvent glue joint. Some rummaging in the brass tubing stock produced a 1/16-inch diameter aluminum (!) tube about 18 mm long: just what’s needed.
So I filed the deformed plastic flat & perpendicular to the stubs, mounted the strut in the 3-jaw chuck on the Sherline’s table, lined the spindle up with the axis, and poked a 1/16-inch hole into the strut. The alignment looks decidedly off in the picture, but it’s actually spot on: what you’re seeing is some swarf clinging to the far edge. Honest!
Then I grabbed the mirror plate in the 3-jaw, lined up on the stub, and drilled maybe 4 mm down, which was roughly to the middle of the ball. The tubing was a firm push-fit in the hole and I hope it won’t over-stress the plastic into cracking.
Gluing the mirror strut
Run the spindle up, remove the drill, grab the strut in the chuck (actually, I had to swap in the larger chuck first), dab some Plastruct solvent glue on both ends, align the strut with the stub (they’re actually square in that section), run the spindle down to ram the tubing into the strut, then a bit more to apply pressure to the joint. I made the total hole depth about 2 mm longer than the tubing, so as to avoid the embarrassment of having the ends not quite meet in the middle.
It’s now back on Mary’s helmet, with a pair of black cable ties ensuring that it won’t pop off, and seems to be working fine. I’m sure the ball joint will fail later this year, although that won’t be due to this repair.
So the bike started making a weird whistling squeak. Noises on a bike are never a good sign, but it took me nearly two weeks to banish this one…
Differential diagnosis:
Toward the rear: not pedals, not chainring
Only while pedaling: not sprocket cluster bearings
Depends on chain speed: not sprocket
Conclusion: it’s the chain.
My shop assistant had done a massive chain-cleaning and lubricating exercise when we got back from vacation, so I guessed that a few links (of 250-ish) had escaped proper lube. I gave ’em a dose that didn’t help, so I went Old Skool on the thing.
Coiled it flat in a saucer, immersed it in denatured alcohol to displace air and water-based cleaner inside the links, then drained the alcohol. Poured a generous layer of light machine oil over the whole affair, let it sit for a day. Drained for a pair of rainy days by hanging from a floor joist in the basement. Used up a bunch of rags while wiping the thing down (I have an oily-waste can, they’re not sitting in a wastebasket).
Misrouted chain in rear derailleur
Put it back on the bike, only to discover the chain was now vibrating something awful. Checked the rear end and found that I’d managed to route the chain through the rear derailleur along almost the right path…
Fixed that and the squeak was still there. OK, it’s not the chain.
The only remaining possibility: derailleur jockey pulleys.
Took ’em off without dismounting the derailleur and, lo and behold, the steel-on-plastic bearing surfaces were bone dry and a bit dusty. They’re supposed to be self-lubricating, which is probably true for the first few thousand miles, but I cleaned ’em out and added a dab of grease.
Problem solved… for a while, at least.
The only downside is that the chain will be flinging oil for the next month, no matter how often I wipe it down. There’s a good reason I stopped using light machine oil on chains!
The Smell of Molten Projects in the Morning 