Archive for December 16th, 2012
The hard-floor brush for our old Samsung VAC-9048R vacuum cleaner began scratching the hardwood floor, which called for some investigation & repair. The Fine Manual doesn’t even mention the hard floor brush, so it’s obvious I’m on my own (as is usually the case). Believe it or not, we actually discussed buying a vacuum cleaner, but the new ones have poor reviews, bulky & awkward plastic widgets on the handle, or suffer from other glaringly obvious faults; although this one is aging poorly, it’s at least workable. Plus, I bought a lifetime supply of bags when it was new and it’s not dead yet.
So, we begin…
The rollers that used to support the front of the brush have worn down, allowing the bottom cover to erode on the floor. The right side ran through something sticky in the recent past:
The left side may not be sticky, but it’s in no better shape:
Remove the two obvious screws, pry the front edge up, and the whole cover plate pops off to reveal the two rollers. They pull straight out of the shaft support brackets molded into the top frame. Even their metal shafts show grievous wear:
The rollers consist of a hard plastic hub supporting a flexible rubbery tire, turning on a 3 mm steel shaft that’s worn on one side (which was downward, of course). The central holes in the rollers probably used to fit the shafts, but they’re now worn to 4 mm ID. The tires were probably a lot larger in diameter, too, back when they were new.
A bit of rummaging in the Basement Laboratory Warehouse Wing produced a bag of vibration isolation bushings that had about the right consistency to become tires:
They’re much larger than necessary, but are now, shall we say, fully depreciated and ready for a new, if somewhat downsized, lifestyle.
Unfortunately, they don’t fit onto the existing hubs, so I can’t use the hubs as a template. Fortunately, I have a lathe and some random nylon stock (with crosswise notches that didn’t pose much of a problem):
I came to my senses before converting this into a 3D printer project. If I had to make more than two hubs, it’d be a good idea to solid-model and print them, even if they’re just barely large enough to allow solid infill:
I’d go for a 3 mm ID to increase the wall width; these have a 4 mm ID to fit the brass bushings described below. There’s no significant overhang and they’d print with no problems. Maybe next time?
The isolation bushings cut easily with a sharp razor knife, so I pared them down to a bit over what I estimated to be the finished roller OD and width:
The 10-32 screw in that shiny new hub serves as an arbor in the lathe, where I held a Dremel tool with a sanding drum down on the compound rest, ran the lathe at its slowest back-gear speed, and sanded the bushing down to what seemed to be the right OD for the tire:
The white snout in front leads to a shopvac that caught most of the dust. The front of the lathe chuck shows it wasn’t perfectly effective and I should have worn a dust mask; my glasses didn’t collect much dust, so maybe my lungs didn’t, either.
A trial fit in the floor brush body showed that this one was slightly too large and the sides needed tapering. The inside view:
The outside view, with the cover just slightly unable to snap closed:
Grinding a bit more off produced a pair of 15.5 mm OD tires which fit nicely. Some careful razor knife work smoothed and tapered the sides:
Brass tubes (from the stash of cutoffs) compensate for the flat on the severely worn steel shafts; a fix that turned out to be much easier than building new shafts:
Then reassemble in reverse order and it’s all good!
I wrapped a layer of silicone tape around the large and slightly worn hard-plastic rear tires, even though I’m sure that won’t last very long at all:
The shop doodle giving all the sizes:
Now, if that doesn’t count as a gonzo repair, I don’t know what would… [grin]