Peter "Sci" Turpin

Finally moving forward again

Wed, 30 Jun 2010 00:05:04 GMT

It’s been a couple of months since I last did any real work on the Bonsai RepStrap. My money’s allways close to the line, and most of it’s been tied up in T-shirt stock. However tonight I bit the bullet and ordered the next batch of parts. So I now have on their way to me:

30x Miniature bearings, 3x10x4mm
10x M3 flanged nyloc nuts
40x M3 10mm stainless pan-head machine screws
50x M3 15mm eye-bolts
50x 0.7mm double-barrel crimp sleeves

Now, a lot of them may sound like pretty generic parts, but I’ve done my research to get just the right ones. The crimp sleeves for example aren’t the plain crimp tubes used in jewellery, but the sort used in sea-fishing. They’re double-barrelled so wires don’t get crossed inside them when crimped and get damaged and weakened. Small (and light) bearings at a good price were also a trick to find. But not as hard to find as the machine-thread eye bolts. While some place do them down to maybe M6, I could only find a single shop providing them with an M3 thread, and only in bags of 50.

To be honest, I’d prefer to have used M3 hook bolts, but couldn’t find anywhere that did them at all. Maybe later something will turn up.

They’ll be used in the wire tensioning system along with the flanged nuts and wire crimps. The crimps will hold secure loops of 0.7mm nylon-coated steel cable. Those loops will be fed through the eye bolts. The eye bolts will be retained in a recess by the flanged nuts. The recess will stop the bolt from turning as the nut is adjusted, pulling the bolt further into the recess and putting more tension on the drive wire that runs around the geared capstan.

That’s the theory anyway.

Until they turn up, back to casting and designing T-shirts.

Off to Focus in the morning, looking for some specific storage boxes and some 12mm mouldings. In turn to build the new cargo hauler around, and tidy up the rough Bonsai frame.

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Small update

Sun, 20 Jun 2010 21:15:58 GMT

Took a momment out to update the RepRap wiki entry on my printer project.

http://reprap.org/wiki/Bonsai_RepStrap

I think some of the connections I made at the convention at the weekend may be a great deal of help in building them too.

I’m wondering that when the first few machines are working, that I might loan them out to a few artists to see what they can do with them. See what less hardcore engineering purposes they can find for them.

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Sorting out

Sun, 20 Jun 2010 20:25:59 GMT

Reprap
Thanks to friend dingotush, the stepper driver circuit is now working!
Think I’ve currently got a pair of phases crossed though, as it jerks quite badly every so often. The motor also gets hot very fast, so I think I’ll have to get some current limiting on the go as well.

Casting
The moulds are cleaned up from the last bad casting and sitting overnight to let any acetone residue evaporate. Fresh casting in the morning.

Will also tidy up the feline nose with some sandpaper and get it ready for a proper production. Same with trying adding a vent to the Razor claws. Going to aim to have some completed demonstration paws at Confuzzled, as well as new display stands for a number of items.

Also aiming to have the commissions book totally clear before the con.

Heard back from Cosmo very quickly, so now I’m just gonna be ticking boxes.

Also, I’m amazed that some of my YouTube videos have now been viewed hundreds of times. One even over a thousand. There’s nothing even very good on there yet!

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Power, lathes, wings

Sun, 20 Jun 2010 19:18:46 GMT

Reprap prototype PSU is done and ready for the stepper controllers to arrive now. All boxed up nicely. If memory serves, it didn’t have a fan when it was in the fax machine, so should be fine in the enclosure. At worse I might have to drill it some extra air holes.
Mains lamp, some (vintage) terminal posts, switch and IEC C14 socket.

Even took the engraver to the front panel to mark out the various terminals and added a couple of ferrite beads to the lines to be on the safe side, and used some cable wrap to keep the wires tidy.

Today I also finally removed the piston and cam off the old compressor pump, and filed down a pully to fit. I’ve hooked this up to the 3rd party headstock from the Black and Decker extruded aluminium wood lathe I found last year. It’s meant to be run by a type of drill they no longer make, so the compressor motor should be easily powerful enough. Currently getting a head speed of about 3200rpm, so it’s currently about twice as fast as it needs to be. Will see about swapping the headstock pully for something larger (I have one, but getting the old one off will be a pain).
It’s not urgent, but it’s sitting around and there’s a friend who should be able to use it once it’s basically working.
Also made a control box for it, currently a simple latching safety power switch (see background of first image) from a broken garden shredder and an old RS project box. If I find a spare suitably rated rheostat I may add a limited speed controller.

Also the sewing for the set of “Navi” wings was mostly done today, but one of the blue plastic rods snapped while trying to flex it into it’s “pocket”.
After some considerable swearing and therapeutic angle-grinder time (see above compressor pump), I will tomorrow attempt to construct a coupler out of clear perspex rod and use it to join the two broken ends, as the stress on them will likely be more than any other repair would take. this may mean purposefully breaking and repairing the opposite wing to match.

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PSU Wiring

Sun, 20 Jun 2010 19:11:42 GMT

Some progress with inventory today, but got a bit sidelined into working on the old fax machine PSU, which puts out 5v and 24v, and should be powerful enough to run the stepper control circuits.

Boxing it up is fairly important, especially if there’s the chance of metal filings wandering around.

Using an old comms relay box of some sort and making a new front panel out of some aluminium plate from some Dell drive tray blanks.

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Sun, 20 Jun 2010 19:06:14 GMT

Spent most of today creating inventory templates for workshop stock. After unexpectedly running out of materials yesterday, I’ve realised I need to manage it all much more actively.

I also have an order of electronic sundries on their way to me, including some Darlington transistor arrays and stepper-driver ICs. This should be enough to get prototyping of the Bonsai Repstrap to the next stage.
Comparing the price of dedicated driver ICs, I’m wondering if I couldn’t make quite a saving (on cost and part-count) by using a Sanguino rather than direct Paralell-port control.
The Reprap still uses stepper driver ICs as well, but could a Sanguino drive the Darlington array directly? It sounds like it would have enough processing power spare to manage the sequencing.

Anyway, time to see how the castings are doing in the heated cabinet, and get some inventory done.

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Sun, 20 Jun 2010 18:59:17 GMT

Run out of Shore 40. Need to order some more in and write up a proper supplies tally sheet so I don’t get caught short again in future. Only one current order should be affected.

I’m also down to the dregs of the water-clear resin. Will probably only restock on demand for the moment.

Also have created a page for the Bonsai Repstrap on the RepRapWiki; http://objects.reprap.org/wiki/Bonsai_Repstrap

Need to place orders for more shirts for Confuzzled in a months time. Hoping to have one of my own designs included in that order.

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Some progress

Sun, 20 Jun 2010 18:53:39 GMT

I have not been coping well today.

Footpads haven’t bonded correctly. Gluing method hasn’t worked very well. I guess the rubber chemistry changes while setting. Unset won’t bond to set.
Going to have to try slashing the velcro to get rubber to bond into it better.

Still, one set come out acceptable.

More casting tomorrow. May catch up yet.

Also roughed out the folding mechanism for the Bonsai Repstrap..

A portable 3D printer is certainly feasible.

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Three things

Sun, 20 Jun 2010 18:40:57 GMT

Once again, things have been busy here! I’m currently processing orders, albeit with a small delay (manifold broke off the degassing chamber and I’m waiting for the glue to set).

There have been two major developments however.

UKFur
I’ve now purchased the UKFur merchandise shop from previous owner Tigerfire, who’s no longer as involved in the Furry scene as he once was.
In the next couple of days I should receive the first batch of new stock, to get a small number of the most in-demand shirts and sizes.

The three designs of shirt

It’s out of stock of the lanyards, but I’m looking around for a supplier that will provide them in minimum orders of less than £200.

However still have large numbers of vinyl stickers and silicone wristbands.

Confuzzled is just a month away now, so have no fear, you will be able to get your UKFur merch!

In the meantime though, wristbands are £1.50, stickers are 50p each.
B&W shirts are £10 in Small to XL sizes, and £11 in XXL and XXXL.
Blue shirts are £12 in Small to XL sizes, and £13 in XXL and XXXL.
£2 for postage, and I still take paypal.

If I’m out of stock, let me know the size you’re after so I can get more in and I’ll let you know when I do.

Chest sizes: S – 35/37″ M – 38/40″ L – 41/43″ XL – 44/46″ XXL – 47/49″ 3XL – 50/52″

Reprap
Shortly after buying the UKFur shop I also acquired a lot of 2000 surplus stepper motors.

All boxes full of motors (ignore the SEM bits)

I strongly believe the future is in 3D printers, but there’s a big supply issue. Even the home-made machines tend to require you to already have a 3D printer to make parts for it.
The way around this is to make a bootstrapping machine to make the initial parts. A rep-strap.

The motors I have are smaller than those advised in the Reprap project, but I have my own take on it. I’m developing a small, semi-portable 3D printer, that should be fairly cheap and easy to modify. I’m looking at a sale price in the £200 range, and a quantity of around 500 machines.
Because of the small size of these printers, I’m dubbing it the Bonsai Repstrap.

It’s an ambitious project I know! But if you want to follow how things are going with it, take a look at..

The Creative Blog
I’ve set up a journal over at Dreamwidth as a stand-alone creative blog. While this won’t be strictly business related, it will include and business creations and day-to-day activities as well as my personal works.
Dreamwidth incorporates RSS feeds into the blogs, so you don’t have to sign up to follow it. It also accepts OpenID logins, so you can comment if you like.

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Sun, 20 Jun 2010 18:24:22 GMT

Contacted shirt supplier. Should be able make an initial small-order with a penalty fee, but it’ll get in the stuff there’s demand for.
Also enquired over getting patches made. Ballpark prices fairly reasonable. But don’t think I could get much of a markup on them. Still..

Received in the post today; 24 DIL sockets. Should allow quick replacement of the 4N35 photo-isolators on the parallel port breakout board I’ll be making for the Bonsai reprap. I really don’t want to kill the workshop PC, after-all. Nor do I want to have to re-solder the board when something inevitably goes sparkly-wrong.

Currently doing inventory on mobile shop stock. Almost there.

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Sun, 20 Jun 2010 18:20:56 GMT

Paw-pads:
Well, the Shore 75 rubber is now here, the 60 has been returned. I’ve not yet caught up with the orders though. There’s a rare collective motivation going on in the house right now that’s saying “Yes, let’s actually clear stuff out!”

Workshop:
Over the past few days I’ve filled one of the wheelie-bins all by myself just with stuff from the workshop. And there’s more yet to come!
It’s been a really harsh thing to do though. I’m a packrat, and I do tend to use the things I pick up sooner or later. But it’s best not to dwell on it all. The space is far more important atm.

Reprap:
Ordered some more Bonsai prototyping bits, but the aluminium tube was out of stock in the end, so I’m going to have to go with stainless instead.
You see, the first simplification I’m making to the Mendel layout is to use the frame as the runners by wrapping the studding with push-fit tube. It should also have the benefit of making assembly and adjustment easier, if I cut the pipes to the correct lengths. Just assemble and tighten.

Art-bike:
Also stripped down the big bicycle frame someone dumped in the alleyway. The front fork stem is the same diameter as the stem on the unicycle I picked up last year. Will have to do some careful grinding and welding, but fitting the unicycle up as the front wheel should be fine. And the frames pedal cranks look like they’ll swap with the unicycle ones, so I can hopefully get the mechanism I was after working alright.
It should make it all into a nice half-horse and buggy. Eventually.

Blacksmithing:
I’ve got a rough forge assembled, but I still need to line it with refractory. Have fire cement and perlite, but think I need to pick up some dry sand too. Well, and some charcoal.

Video:
Got some footage from the digital camera that needs editing. Also haven’t yet tested the capture machine I assembled last week. It’s on my to-do list.

T-shirts:
Seeing who’s interested in what types and sizes. Think I can afford to get one atm. No reply from supplier atm. Will call them in the morning and make an order for the large blue UKFur shirts.
Also converted the carrying case that came with the shirts into something more like a portable shop by chopping down an Ikea hanging rail and mounting fixings inside the case. Now I can store the rail inside the case and use the case as the base of it.

Art:
Yeah, I’m behind on this. But I am catching up.

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