Peter "Sci" Turpin

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After 6 months of waiting I noticed Chester had the Eagle 25 mill on special offer. I called them and found out that this indeed meant the new lot of mills had arrived!
I borrowed some money to pay off the outstanding bill on it and got delivery arranged as soon as possible, since I didn’t want mine to be the last of the lot for a couple of reasons;

• If there was something wrong with it, I wanted there still to be one to replace it with.
• If I waited until there weren’t many left, I’d risk getting the obviously less than immaculate ones.

So yesterday around 3pm, it arrived!

I’d had some trouble with Chester when trying to find out how large the actual crate would be, since it was coming to a domestic property and we have a nice domestic garden-gate it’d have to get through. I’d been told it was 90cm wide, so to expect packaging a few cm larger than that. So as a result I was fully expecting to have to dismantle it on the pavement outside to move it in.

Fortunately the crate, once off the pallet was just small enough to fit into the front garden. :)

The reason for this was it’s packed diagonally to save space, so the crate wasn’t as wide or deep.

And there she is. :3

Checked the manual and with help from Andy, broke it down into; the base, motor, headstock, and column. Then we lugged it through to the workshop.

Whew! That’s a hell of a weight off my mind now.

I generally like the layout, though there’s a couple of niggles; the belt housing lacks an extra hatch that’s in the manual so it can be opened when the head is in a lowered position. It also has mains cabling running through it within milimeters of the spindle pulley. The quality of the table casting is also a bit rough. But of all the Chinese tools I’ve bought it’s probably the best, and I bought it understanding it would need tweaking.

It’s the R8 taper version with metric leadscrews (2mm pitch). I’ll need to make some adaptors and stand-offs for the the table portion.

The top-box should come off fairly easily, though the spindle pully is a lot larger than I expected. This might make it trickier to position the big DC motor. But overall nothing has been thrown up that can’t be overcome.

I’m going to knock a couple of other small projects out of the way before I really get started on it, but should be able to work on it pretty easily come the new year. :)

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Recorded a little bit of video from the workshop last night. Dumped it up to YT. Going to try and do this more often.

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Very tired and about to go to bed, but traced and ID’d most of the parts on the old treadmill motor controller board.

It drives a motor rated for 180v DC, but my measurements say it’s putting out 330v DC which would make sense for rectified UK mains. I suspect on looking at the board that for UK use they dial the speed control trim-pot down to half so the PWM signal never goes above 50%.

Still means the motor’s running at twice the voltage it should though, which’d explain the overheating issues.

I don’t understand the circuit fully though. For one thing there’s a half-bridge rectifier essentially bridging the motor terminals. Surely that’d mean it’s perpetually shorted out? I don’t understand it, but suspect it might be something for dealing with back-EMF from the motor.

I also don’t understand how the MOSFET’s driving it. It all seems to be coming through a 5Watt resistor and some very thin traces, especially since the motor’s 2-2.5HP (1400Watt+). Maybe it’s because it’s late, maybe I’m just not seeing it and it’s just the trigger. Just can’t see it right now. But the circuit does work (even if the fuses and current breaker don’t. If something shorts it ALLWAYS knocks out the 30Amp breaker for the workshop).

It’s a single-sided PCB. Here’s my notes on it. A few figures are missing, but all components are marked.

I’m planning on making a much simpler control circuit, but it does involve a very large 220-110v transformer to get the proper 180v DC.

It’s been a good day. Castings done, experiments done, oscilloscope usable again, found artial pressure cooker for new vacuum degass chamber, some clearing up done.

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I’ve been holding off buying more casting supplies, because I was in dire need of a better way of storing them. The old fridge-freezer I’d been using was simply too small, and particularly in this damp weather I want somewhere dry and warm to be able to store the supplies where they’ll last longer.

Two weeks ago I managed to grab a large commercial display fridge off ebay, and after a lot of problems with the local garage and our van we managed to collect it.

Well actually we got within 0.7miles of collecting it before the van fuel-pump failed (which we’d repeatedly asked the garage to check, but they knew best & instead changed the distributor cap & leads. Not going back there now.). Thankfully the seller brought it down to our van in their car, so we got to get towed home with it in the back.

Today I finally managed to get it moved into the workshop.

It’s a big square insulated box. The glass door is a small concern, but I suppose it’ll get me to keep the place tidier.

I got the wiring tidied up and moved around. The refrigeration still works, and I’ll be seeing if it’s possible to use it as a dehumidifier. As you can see in the quick cameraphone pic, the oil-filled radiaitor currently takes up a lot of space, so I’ll be seeing it I can improve that, possibly by changing it for a filament heater (though I’m concerned about fire risk). Will be adding a couple of fixed temperature sensors at some point to trigger the fan and try and keep the temp evenly distributed.

There’s a hole at the top that also needs plugging, where the neon lamp used to be. Silly bit of design, but easier enough to work around.

Tomorrow I start work on moving everything I shifted to the other side of the workshop back again, so I can actually use the place and get on with the current orders.

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While it’s probably nothing special to many, I’m very glad when I can aquire replacement computer hardware. Especially when it’s free and in a better state than my existing stuff.

For a little while now, the workshop PC had been running on it’s secondary IDE channels only. It was a 1.8Ghz  P4, but with USB 1.0 and PC133 RAM. It crawled at most things and took a few minutes to start with little to load. It also didn’t cooperate well with the PS3 Eye camera I picked up a few months ago. The memory bus was slow enough it choked even once I got a dedicated USB 2.0 card for it.

Some kind soul donated a bunch of used machines to the London Hackspace a fortnight ago. Mostly older Dell machines and a few oddities. Nothing that could be expanded much (except the 5000 which got re-purposed by the space itself). After examining a few I selected to re-home a Dell Dimension 4550 with an 80Gb HDD.

Dell Dimension 4550

The case was marked as having a 31Gb drive, but I don’t know where that number came from.

I got it home and pulled it apart. Got it cleaned of dust and fluff and found some leaky caps on the mainboard, hidden under a cowling. They got replaced with some caps I pulled from some obsolete server gear some time back.

Bad bad caps, no motherboard for you!

After running it for a few hours on the original RAM, I started upgrading. I’d already replaced the epoxy(???) thermal pad with some good thermal grease. I had some 400Mhz DDR sticks around, which fortunately worked (though underclocked) even though the machine is spec’d for 266Mhz. That got the RAM up to 756Mb.

The official spec says the machine can take 1Gb of RAM, but it can actually take 2Gb. There’s just only two RAM slots.

All clear after the transplant

I swapped in the best AGP x4 card I had (which came from the former workshop machine; a GeForce MX4000 128Mb),  put in a better optical drive (which was capable of opening when the case was on it’s side, unlike the original), the USB 2.0 PCI card (because the PS3 Eye apparently needs an entire USB controller to itself) and added an extra hard-disk.

I spent a few hours transferring files around to get all the data from the previous two workshop machines onto this one, then juggled some more while I formatted one drive to do a clean install, then transfer data across and format the other. The 80Gb disk that was already in it was reporting some bad sectors in SMART, so it’s been relegated to the D-drive/storage-disk where I’ll stuff music and video capture files. Non-critical stuff.

(Yes, I’ll be annoyed if I loose a long capture, but I’ll probably just get some corruption rather than losing a file outright.)

The machine’s primary 80Gb was partitioned in two again for dual-booting. I got XP Home installed on one since I couldn’t find the old machine’s XP Pro key certificate and the Dell case already had a Home key sticker. I’ll get round to installing Ubuntu on the other partition once I decide which version to go with. 10.10 I didn’t like much.

It’s now in the workshop, running fine on the extra workbench I built last week. The PS3 Eye works fine with it and I’ve managed to successful do a test Livestream with it and record video to disk (though still need to find some on-the-fly compression that’ll work with the camera format).

Installed in place

It’s also whisper-quiet! :D

Only annoyance is the front-panel lights are barely visible. They’re so dim you have to kneel in front of it and concentrate to tell they’re on. If I get a free moment I *may* try to replace them with better LEDs, but for such a minor thing it’s really not worth it. If I really need to know if the HDD is running, I’ll be willing to bend over to see.

An additional bonus has been realising the old PC’s case is perfect for another project! My hope to build a desk from all that mahogany I have was also one to have a PC installed directly within the desk’s structure. The old case was riveted together with a motherboard tray held in with screws! A few minutes with the drill and I have the rear of the case with all the needed mounts and the tray to mount a motherboard on! I can plan more about the future desk around these parts. :)

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I should be clearing up.

I should be doing exercises.

I should be learning more database theory, writing adverts, making moulds, doing accounts, doing innumerable small odd-jobs to get in a smidge of extra cash.

But I’m not.

I’ve indulged myself this last couple of days and it’s felt good. I’ve been tinkering in the workshop.

Long story short, I’ve been trying to motorise the angle-poise lamp I have the webcam attached to, with a view to getting it hooked up to some machine-vision software for motion-tracking and having it run as cameraman. At least it started there, and now I’m looking at adding microphones, a speaker and tri-colour LEDs to turn it into a sort of intuitive feedback device.

It’s essentially a robot arm though, with 6 degrees of freedom. I’ve never made a robot arm before. I also have no spare money to throw at it, so I’ve been running through my various parts bins.

Collecting “useful” things, and/or taking them apart to see how they’re assembled is something of a compulsion. However actually recombining them feels like something I’ve let atrophy. It’s been frustrating at points, but it’s an enjoyable indulgence. And it feels like it’s starting to get back into gear a bit.

It’s also helpfully letting me see what parts are actually still any use to me.

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Old 1.7Ghz machine is out of storage. Running diagnostics to see if I can isolate where the hardware problem is (I suspect the 80Gb boot disk), before installing Win2000 and a capture card on it. And nothing else.
Will also put the old 5.25″ floppy drive in it and see if any old disks still work.

Yesterdays castings are de-moulded. Unfortunately two sets show small areas of unmixed pigment. Will have to double-stage mix it from here on. Still, getting closer to high-resolution shots of all sets, as well as having display sets.

Called TOMPS, still no word yet. Sounds like the boss is out of the office a lot these past few days. Still, have someone wanting a footpad order, and won’t be able to honour it until I have the shore-80. It’s been a week since I emailed them about this.

Up to 9 Mendel brackets cast. Should have the rest needed in an hour or so. I’ll lock up again for a bit after that, get some artwork done, before casting some more pads in the evening.

Had a reply back from the connector company, wanting to know the pitch of the connector image I sent them. I thought I’d included that in my description. Yep. Ugh..

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DorkBot London was very entertaining last night. My main point of confusion had always been that I’d never found where they talked online. Simple answer; they don’t. You go along, meet people and then communicate one-to-one. This seems surprisingly traditional for such a techno-arty field.
I suppose things like the 2600 meets are the same though. It just feels a little upside-down to me though, having mostly gone to groups or forums which then sparked real-world meetings.

EDIT: 5.25″ drive seems to be working intermittently. Will have to strip it down and clean it.

[20/06/2010: Amalgamating old posts from "Dreamwidth Creative Blog" into sci-fi-fox.com to re-purpose DW blog account.]

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