Ed Nisley's Blog: Shop notes, electronics, firmware, machinery, 3D printing, laser cuttery, and curiosities. Contents: 100% human thinking, 0% AI slop.
The drawbar bolts on a Sherline mill (and, presumably, the lathe) have a fitting that adapts the bolt head to the top of the spindle. There’s nothing to keep it from sliding right off the bolt, which happens 100% of the time when you just pick up the drawbar.
The fix is easy: a short length of heatshrink tubing applied near the bolt head.
I happened to have some tubing with an internal hot-melt glue lining that stick like, well, glue to the bolt. Pretty nearly any heatshrink tubing will work, although you might need two layers to catch the fitting’s ID.
Sherline drawbar bolts with heatshrink tubing to capture the fitting
This is a nuisance you gotta do once in a while. The symptom today was that the mill axis didn’t line up at all with the laser aimer I have mounted on the ceiling; it’s supposed to point right down the spindle bore, but the bore wandered all over the place. Took me a while to realize it was really that bad…
Basically, you must take the headstock off, unplug the axis motors, and put the mill on the workbench so you can get convenient access to the back of the column. Unscrew the cap screw holding the Z-axis backlash lock plate and disconnect the saddle nut. Make sure the lock doesn’t engage.
Loosen the gib lock, remove the gib, clean the crap off the mating dovetail surfaces & gib, add a touch of their approved silicone lube, slide the gib back & lock it in place. Slide the saddle up & down (that’s why you want the saddle nut disconnected) and tweak the gib until it slides more-or-less freely along the entire length without binding or being too loose. My saddle gets stiff near the very bottom of the column, but it never gets that low in actual use. Make sure the gib lock is tight.
Run the saddle nut to the top of the leadscrew, slide the saddle in place, back those two tiny setscrews out, secure the saddle nut to the saddle with a short cap screw, then turn the setscrews until they just touch the nut.
At this point, the nut should be in its nominal position, centered on the leadscrew and aligned concentric with its axis. If you turn the Z-axis knob and it binds, then you get to loosen the cap screw, futz with the setscrews, tighten the cap screw, check for binding, and iterate until it works properly.When it’s OK at the top, crank it all the way to the bottom and verify that it doesn’t bind elsewhere.
Mine took one iteration this time, which is just sheer blind good fortune. Or maybe the saddle nut is wearing out and getting sloppy?
Then adjust the backlash lock to reduce the backlash to whatever you think is appropriate. My Z-axis has a few mils unless that thing is way too snug.
Sherline’s instructions for aligning the saddle nut screw that connects the leadscrew to the saddle are on Sherline’s site, hidden in the instructions for the “new” Z-axis backlash adjustment: http://www.sherline.com/4017Zinst.htm.
For the last few months, one of the USB hubs in my PC has been disabling a port connected to an external USB hub. The external hub re-establishes communication with all the devices, but the X server doesn’t take kindly to having devices yanked out from underneath it. After this glitch, my left-hand trackball and tablet are dead in the water; the only way to get ’em working is to log out, restart X, and log back in again. Not pleasant.
Oddly, the keyboard continues to function.
Note that it’s the hub in the PC that’s complaining, not the external hub.
USB connections at PC
I’ve tweaked the obvious things: switched USB ports on the PC, replaced the external hub, powered and un-powered the external hub, rearranged the devices on the hub, moved other devices away from the hub, and so forth and so on.
Now it’s time to start taking notes. The current external hub is a cheap, no-name gadget direct from China that bears a striking resemblance to the tchotchke HP-branded “Made In China” hub a friend picked up at SC06.
Both hubs have a cut-out in the case for a power plug, but the internal circuit boards lack the requisite jack to actually make use of external power.
Here’s the current dmesg dump.
[ 2917.702975] hub 1-0:1.0: port 2 disabled by hub (EMI?), re-enabling...
[ 2917.702986] usb 1-2: USB disconnect, address 3
[ 2917.702989] usb 1-2.2: USB disconnect, address 4
[ 2917.712300] /build/buildd/linux-2.6.24/drivers/input/tablet/wacom_sys.c: wacom_sys_irq - usb_submit_urb failed with result -19
[ 2917.787223] usb 1-2.3: USB disconnect, address 5
[ 2917.831161] usb 1-2.4: USB disconnect, address 6
[ 2918.002420] usb 1-2: new full speed USB device using uhci_hcd and address 7
[ 2918.165658] usb 1-2: configuration #1 chosen from 1 choice
[ 2918.170675] hub 1-2:1.0: USB hub found
[ 2918.172533] hub 1-2:1.0: 4 ports detected
[ 2918.502967] usb 1-2.2: new low speed USB device using uhci_hcd and address 8
[ 2918.662816] usb 1-2.2: configuration #1 chosen from 1 choice
[ 2918.679915] input: Microsoft Comfort Curve Keyboard 2000 as /devices/pci0000:00/0000:00:1d.0/usb1/1-2/1-2.2/1-2.2:1.0/input/input10
[ 2918.721211] input,hidraw2: USB HID v1.11 Keyboard [Microsoft Comfort Curve Keyboard 2000] on usb-0000:00:1d.0-2.2
[ 2918.751759] input: Microsoft Comfort Curve Keyboard 2000 as /devices/pci0000:00/0000:00:1d.0/usb1/1-2/1-2.2/1-2.2:1.1/input/input11
[ 2918.793088] input,hidraw3: USB HID v1.11 Device [Microsoft Comfort Curve Keyboard 2000] on usb-0000:00:1d.0-2.2
[ 2919.010108] usb 1-2.3: new low speed USB device using uhci_hcd and address 9
[ 2919.165963] usb 1-2.3: configuration #1 chosen from 1 choice
[ 2919.187020] input: Kensington Kensington Expert Mouse as /devices/pci0000:00/0000:00:1d.0/usb1/1-2/1-2.3/1-2.3:1.0/input/input12
[ 2919.244778] input,hidraw4: USB HID v1.10 Mouse [Kensington Kensington Expert Mouse] on usb-0000:00:1d.0-2.3
[ 2919.465338] usb 1-2.4: new low speed USB device using uhci_hcd and address 10
[ 2919.617208] usb 1-2.4: configuration #1 chosen from 1 choice
[ 2919.625530] input: Wacom Graphire3 6x8 as /devices/pci0000:00/0000:00:1d.0/usb1/1-2/1-2.4/1-2.4:1.0/input/input13
The external hub is on the white cable (a USB extender cable, which may contribute to the problem) plugged into the port at the far right from the network cable. But i’ve used an external hub with a different and very official USB A-B cable.
The USB connections on the back panel:
Top row: Zire 71 PDA cradle | External USB hub (the offending one)
[10625.203907] usb 1-2.2: USB disconnect, address 8
[10625.970605] usb 1-2.3: USB disconnect, address 9
[10626.865087] usb 1-2.4: USB disconnect, address 10
[10627.880887] usb 1-2: USB disconnect, address 7
[10638.410365] usb 1-2: new full speed USB device using uhci_hcd and address 11
[10638.579231] usb 1-2: configuration #1 chosen from 1 choice
[10638.582167] hub 1-2:1.0: USB hub found
[10638.584118] hub 1-2:1.0: 4 ports detected
[10638.898574] usb 1-2.1: new low speed USB device using uhci_hcd and address 12
[10639.035458] usb 1-2.1: configuration #1 chosen from 1 choice
[10639.038484] input: Wacom Graphire3 6x8 as /devices/pci0000:00/0000:00:1d.0/usb1/1-2/1-2.1/1-2.1:1.0/input/input14
[10639.301891] usb 1-2.3: new low speed USB device using uhci_hcd and address 13
[10639.445768] usb 1-2.3: configuration #1 chosen from 1 choice
[10639.466865] input: Microsoft Comfort Curve Keyboard 2000 as /devices/pci0000:00/0000:00:1d.0/usb1/1-2/1-2.3/1-2.3:1.0/input/input15
[10639.505029] input,hidraw2: USB HID v1.11 Keyboard [Microsoft Comfort Curve Keyboard 2000] on usb-0000:00:1d.0-2.3
[10639.525686] input: Microsoft Comfort Curve Keyboard 2000 as /devices/pci0000:00/0000:00:1d.0/usb1/1-2/1-2.3/1-2.3:1.1/input/input16
[10639.572404] input,hidraw3: USB HID v1.11 Device [Microsoft Comfort Curve Keyboard 2000] on usb-0000:00:1d.0-2.3
[10639.777083] usb 1-2.4: new low speed USB device using uhci_hcd and address 14
[10639.917975] usb 1-2.4: configuration #1 chosen from 1 choice
[10639.934026] input: Kensington Kensington Expert Mouse as /devices/pci0000:00/0000:00:1d.0/usb1/1-2/1-2.4/1-2.4:1.0/input/input17
[10639.971692] input,hidraw4: USB HID v1.10 Mouse [Kensington Kensington Expert Mouse] on usb-0000:00:1d.0-2.4
[10962.110496] usb 5-5.2: new high speed USB device using ehci_hcd and address 8
[10962.219819] usb 5-5.2: configuration #1 chosen from 1 choice
[12290.756701] usb 5-5.2: USB disconnect, address 8
[54272.946992] hub 1-0:1.0: port 2 disabled by hub (EMI?), re-enabling...
[54272.947001] usb 1-2: USB disconnect, address 11
[54272.947003] usb 1-2.1: USB disconnect, address 12
[54273.003212] usb 1-2.3: USB disconnect, address 13
[54273.071171] usb 1-2.4: USB disconnect, address 14
[54273.214485] usb 1-2: new full speed USB device using uhci_hcd and address 15
[54273.383873] usb 1-2: configuration #1 chosen from 1 choice
[54273.386778] hub 1-2:1.0: USB hub found
[54273.388736] hub 1-2:1.0: 4 ports detected
[54273.699213] usb 1-2.1: new low speed USB device using uhci_hcd and address 16
[54273.840096] usb 1-2.1: configuration #1 chosen from 1 choice
So replacing the hub seems to have not done anything useful, as expected.
Next step: plug the hub cable into the right-hand port on the bottom row.
Update: Time passes and another disconnect pops up. I’d just poked the USB button on my pocket camera’s cradle. Coincidence? Sometimes it disconnects when I sit down, which suggests a static discharge.
The dmesg dump:
[ 1275.088536] hub 3-0:1.0: port 2 disabled by hub (EMI?), re-enabling...
[ 1275.088547] usb 3-2: USB disconnect, address 5
[ 1275.088549] usb 3-2.1: USB disconnect, address 6
[ 1275.132321] usb 3-2.3: USB disconnect, address 7
[ 1275.220223] usb 3-2.4: USB disconnect, address 8
[ 1275.371502] usb 3-2: new full speed USB device using uhci_hcd and address 9
[ 1275.541198] usb 3-2: configuration #1 chosen from 1 choice
[ 1275.544148] hub 3-2:1.0: USB hub found
[ 1275.546102] hub 3-2:1.0: 4 ports detected
[ 1275.856554] usb 3-2.1: new low speed USB device using uhci_hcd and address 10
[ 1275.993439] usb 3-2.1: configuration #1 chosen from 1 choice
[ 1275.997194] input: Wacom Graphire3 6x8 as /devices/pci0000:00/0000:00:1d.2/usb3/3-2/3-2.1/3-2.1:1.0/input/input10
[ 1276.259871] usb 3-2.3: new low speed USB device using uhci_hcd and address 11
[ 1276.406735] usb 3-2.3: configuration #1 chosen from 1 choice
[ 1276.423836] input: Microsoft Comfort Curve Keyboard 2000 as /devices/pci0000:00/0000:00:1d.2/usb3/3-2/3-2.3/3-2.3:1.0/input/input11
[ 1276.469640] input,hidraw2: USB HID v1.11 Keyboard [Microsoft Comfort Curve Keyboard 2000] on usb-0000:00:1d.2-2.3
[ 1276.490647] input: Microsoft Comfort Curve Keyboard 2000 as /devices/pci0000:00/0000:00:1d.2/usb3/3-2/3-2.3/3-2.3:1.1/input/input12
[ 1276.545539] input,hidraw3: USB HID v1.11 Device [Microsoft Comfort Curve Keyboard 2000] on usb-0000:00:1d.2-2.3
[ 1276.746036] usb 3-2.4: new low speed USB device using uhci_hcd and address 12
[ 1276.896906] usb 3-2.4: configuration #1 chosen from 1 choice
[ 1276.912985] input: Kensington Kensington Expert Mouse as /devices/pci0000:00/0000:00:1d.2/usb3/3-2/3-2.4/3-2.4:1.0/input/input13
[ 1276.960781] input,hidraw4: USB HID v1.10 Mouse [Kensington Kensington Expert Mouse] on usb-0000:00:1d.2-2.4
[ 1280.734257] usb 5-5.2: new high speed USB device using ehci_hcd and address 7
[ 1280.843575] usb 5-5.2: configuration #1 chosen from 1 choice
Bottom Row: Logitech trackball | External USB hub (the offending one) | empty port
Methinks it’s time to start yanking the SD card out of the camera and poking it into the PC’s media reader. That should eliminate one possible source of bus confusion.
Time to reset…
Update: time passes and it’s been working OK… up until I zapped the desk lamp with a teeny static spark, at which moment dmesg reports this:
[49077.518404] hub 3-0:1.0: port 1 disabled by hub (EMI?), re-enabling...
[49077.518413] usb 3-1: USB disconnect, address 2
[49077.518416] usb 3-1.1: USB disconnect, address 3
[49077.562470] usb 3-1.3: USB disconnect, address 4
[49077.658411] usb 3-1.4: USB disconnect, address 5
[49077.805865] usb 3-1: new full speed USB device using uhci_hcd and address 6
[49077.974924] usb 3-1: configuration #1 chosen from 1 choice
[49077.982443] hub 3-1:1.0: USB hub found
[49077.983860] hub 3-1:1.0: 4 ports detected
[49078.302253] usb 3-1.1: new low speed USB device using uhci_hcd and address 7
[49078.439141] usb 3-1.1: configuration #1 chosen from 1 choice
[49078.442156] input: Wacom Graphire3 6x8 as /devices/pci0000:00/0000:00:1d.2/usb3/3-1/3-1.1/3-1.1:1.0/input/input10
[49078.709567] usb 3-1.3: new low speed USB device using uhci_hcd and address 8
[49078.853443] usb 3-1.3: configuration #1 chosen from 1 choice
[49078.875540] input: Microsoft Comfort Curve Keyboard 2000 as /devices/pci0000:00/0000:00:1d.2/usb3/3-1/3-1.3/3-1.3:1.0/input/input11
[49078.920499] input,hidraw2: USB HID v1.11 Keyboard [Microsoft Comfort Curve Keyboard 2000] on usb-0000:00:1d.2-1.3
[49078.941372] input: Microsoft Comfort Curve Keyboard 2000 as /devices/pci0000:00/0000:00:1d.2/usb3/3-1/3-1.3/3-1.3:1.1/input/input12
[49078.999851] input,hidraw3: USB HID v1.11 Device [Microsoft Comfort Curve Keyboard 2000] on usb-0000:00:1d.2-1.3
[49079.212710] usb 3-1.4: new low speed USB device using uhci_hcd and address 9
[49079.351593] usb 3-1.4: configuration #1 chosen from 1 choice
[49079.367726] input: Kensington Kensington Expert Mouse as /devices/pci0000:00/0000:00:1d.2/usb3/3-1/3-1.4/3-1.4:1.0/input/input13
[49079.411112] input,hidraw4: USB HID v1.10 Mouse [Kensington Kensington Expert Mouse] on usb-0000:00:1d.2-1.4
So it looks like there’s really something EMI-ish going on. Perhaps it’s time to look into grounding all the exposed metal around here.
Update: It really was static electricity. More discussion there.
Flash is one of those things that comes heartbreakingly close to actually working, particularly in a 64-bit Linux OS. There’s an intricate scaffolding that plugs the 32-bit Flash code into the 64-bit Firefox superstructure, but …
Worse, there’s an error in the Hardy Flash 10 repository entry that points to a nonexistent Macromedia download website, so all the usual hints & tips don’t work. That seems to have broken in December and the automatic installation fails quietly. Using sudo apt-get update flashplugin-nonfree reveals the problem.
Unfortunately, the sum total of all my fiddling was a Flash installation that sorta-kinda worked, with a significantly flaky crust.
What works slightly better: force the version to Flash 9 by pinning the flashplugin-nonfree package version in apt-get. Start by removing everything related to Flash. Then, with a clean slate, this post on the Ubuntu forums shows how to get a clean installation:
1.) Create /etc/apt/preferences with this entry:
Explanation: Flash plugin from hardy-backports was broken on 12/24/2008;
Explanation: pinning to hardy-updates for now until it is fixed
Package: flashplugin-nonfree
Pin: release a=hardy-updates
Pin-Priority: 980
2.) sudo apt-get update
3.) sudo apt-get install flashplugin-nonfree
4.) Restart Firefox
It still gives me a blank gray background where the Flash should appear, which is sometimes cured by reloading the page, but it seems more stable.
Adobe has a genuine 64-bit Flash alpha out, but (as of the 16 December 2008 version) it reliably crashes on sites I really care about. Like, for example, nytimes.com.
Memo to self: un-pin this in a few months and see what happens.
Update: It still jams up with gray screens where Flash should be, no matter what I do.
Inside a batteries.com 9V batteryCorrosion inside batteries.com 9V battery
Back in the Good Old Days, 9 V batteries had a stack of half a dozen pancake cells inside that completely filled the outer case. These days, it seems they use cylindrical cells similar to AAAA cells, with more wasted space around the edges.
I retrieved these batteries from our smoke detectors. I tend to poke the self-test button occasionally and wait until the low-battery alarm starts chirping, rather than throwing half-used batteries out. Being that sort of bear, I date the batteries when I put them in; they usually last two years.
This one is from batteries.com and lasted 18 months. The obvious corrosion inside the shrink-wrap plastic sleeve says that the cell sealing isn’t nearly as good as you’d wish. The two most heavily corroded cells are completely dead, but the rest have about 500 mAh of life left in them (at a rather low 50 mA discharge rate). With a bit better QC, it’d be a winner.
Notice that the case contacts have sharp points that ensure a decent connection, perhaps despite the crud. Only one or two of the points actually make contact, which probably contributes to a faster assembly time: just get the ribbons in the right neighborhood and crimp the case closed. On the other hand, all the current must flow through one or two points, so don’t use them as a high-current source.
Eveready Gold 9V battery innards
On the other end of the scale, this Eveready Gold battery has six loose cells and lasted 2.5 years. All the cells have roughly the same level of charge remaining: they’re thoroughly dead.
The build quality seems better, with individually shrink-wrapped cells and a compliant closed-cell foam layer on the bottom of the case to maintain pressure against the contacts. No sharp points, so they need more pressure.
The cell polarity is exactly reversed from what you’d expect: the button end is negative. So, even though this looks like a cheap source of AAAA cells, that’s a cruel deception…
Ever notice how, when you take your car in for inspection, it always comes back with the wheel lug nuts tightened beyond the ability of mere mortals? I think it’s because they have their pneumatic impact wrenches turned up to 11, just to make sure the nuts never, ever come loose and expose them to liability.
Broken wheel lug with attached SocketLug
Found this yesterday while walking back from the store with two gallons of milk. The shiny bit in the background is labeled SocketLug, which is evidently a trademark associated with Gorilla (but with no Web presence), and sports patent number 5797659. The stud in the front evidently snapped out of somebody’s wheel, probably flush with the surface. Gonna be trouble getting that out!
The lug is a threaded 9/16-inch steel stud, with a root area of maybe 0.18 square inches. Let’s suppose the yield strength is 100 kpsi, so breaking that thing required 18 k pounds. The thread looks to be 18 TPI for a 1.8 degree helix angle; call it 3%. If they lubed the threads and lug (ha!), letting us assume 20% friction, then the wrench was applying 700 pounds at a 9/32″ moment arm: call it 2.5 k lb-in or 30 k lb-ft of torque. Pretty impressive, given that typical pneumatic wrenches weigh in at around 500 lb-ft of torque.
Which says it really wasn’t the wrench doing the breaking, which should also be obvious because it was lying at the side of the road rather than on the shop floor. Even a 1000 lb-ft wrench would create only 5% of that yield load in the stud, so something else was wrong.
That orange patch in the upper left looks like rust in a crack, with the gray area in the lower right revealing the final fault. Maybe the shop monkey (or owner?) managed to whack it while installing the tire, create a small crack that let in the usual NYS road salt, and after a season or two the stud failed after being cranked tight once again.
There’s likely another four on that wheel: safety in numbers! Unlike those old Citroens with but a single nut securing each wheel…
The question came up as to whether an external hard drive with a network interface was a Good Thing for backups and suchlike.
For humongous drives, a 100 Mbit/s network tap is painfully slow. In round numbers, on a good day you’ll get 80 Mbit/s throughput; call it 10 MBytes/s.
Transferring 1 TB at 10 MB/s requires a bit over a day: 28-ish hours. Streaming media will work fine, but filling up the drive in the first place will be tedious.
I was reminded of this the hard way when I had to do a full-drive backup to the file server in the basement. Seemed to take forever, but when I ran the numbers it was ticking along just about as fast as it could possibly go…
A USB local drive is better: 40 MB/s, more or less, if the software stack can keep up with it. I eventually pulled the drive, popped it on a USB-IDE adapter, jacked it into the server, and got it done that way.
Now, if you have gigabit Ethernet everywhere, things might be faster, but the limiting factor then becomes the drive’s sustained rate, which is probably a tad over 100 MB/s if you’re transferring large files.
Fancy eSATA drives have a higher burst rate, but the bits just don’t come off the platters all that much faster.
I’d be astounded if a consumer-grade network drive came anywhere close to those numbers. I have an IOmega 500 GB drive that’s an absolute piece of crap…
Feed the obvious keywords into Wikipedia and get all the numbers.
The Smell of Molten Projects in the Morning 