Oct
20

Week 42, 2013 – PCB Process Revisited

So, as some of you know, I’ve had no end to trouble producing printed circuit boards (PCBs); there’s always some damn thing that isn’t quite right…  Toner transfer is always a crapshoot, quality-wise.  And photo-resist is iffy because my laser printer can print good high-density positives, but not negatives, and my CraftRobo can’t cut rubylith fine enough for the kind of PCBs I’m making…

I’m left with two options;  Screen-printing resist to the board. (Since burning screens is a positive image process)  Or! Using lithographic film in an emulsion-to-emulsion contact exposure with my laser printer transparencies to yield perfect high-contrast negative films to expose the dry film laminated photo-resist on the PCBs with.  (I can also use lithographic ‘duplicating film’ to turn so-so positive transparencies into film positives with perfect contrast.)

Right now I’m just waiting on money for supplies.  Like a hundred bucks in chemicals, film, and darkroom stuff.

In the meantime, here’s some YouTube links!

Oct
13

Week 41, 2013 – Digital Readout

A couple years ago I bought a bunch of cheap Chinese digital calipers with the notion of using them to build my own DRO (Digital Readout) for a mill or lathe, or getting one from ShumaTech which now seems quite defunct.  A couple weeks ago I stumbled upon a newer project using an Android device as a DRO, with a simple Arduino hardware interface to some magnetic scales.  The developer has since added support for the Texas Instruments MSP430 Launchpad board, and is in the process of adding support for the cheap Chinese scales and calipers.  I’ll do a full write-up when I build the system.  (I’ll be installing it on the lathe, since the mill will be converted to CNC in the near future.)

He was supposed to release an updated version of the firmware that supports the Chinese calipers the weekend this was originally posted, but it’s been two weeks now, and nothing.  So I think I’m going to have to get back to writing my firmware now that I have my sample voltage shifter chips from TI.

Oct
06

Week 40, 2013 – Shars Tools

I fell a bit behind; I had these posts partially prepared but never posted.  I’m going to try and add at least a couple links and pictures later.

So I made an order from Shars Tools.  Shars is where I’ve gotten the majority of the tooling and instruments for my machine shop.  It’s basically the Made-in-China-dot-com of the machine tool world, and judging from the AOL and gmail mail addresses, I swear it’s run out of somebody’s house, and they don’t actually have any inventory, it just comes direct from China and they send it off to customers…it really wouldn’t surprise me in the least. But their prices are hard to beat, they’ve got one of the best selections, and their customer service is good and very responsive, especially considering it really does seem to be run by like ONE PERSON.

This time I picked up some handy bits and bobs, for instance, a set of telescoping gages, and a direct-reading ‘mechanical digital’ micrometer accurate to 0.0001″.  Very good tools for inspection.

I picked up some new inserts for the indexable tools for my lathe; since I can’t run it fast enough to reach the optimal cutting speeds for carbide inserts on aluminium I’d been meaning to get some aluminium-specific inserts…which are sort of hard to find for some reason.  I also picked up a matching indexable boring bar.  I wanted to get a pair of internal and external indexable threading tools with special thread-forming inserts, but they were like $30 each.  Need to do that though if I’m going to really do any serious fabrication on the lathe.  I also had my eye on this great grooving and profiling tool.  Profiling will be a big deal if I ever convert the lathe for CNC.

Also picked up an indexable dovetail mill for the milling machine.  I figured it didn’t cost that much more than the non-indexable version, so screw it. This way, any time it gets dull, I can just replace the cutting edges instead of buying a new cutter. Inserts are relatively cheap.

Sep
29

Week 39, 2013 – Some Projects and Some Links

Projects

I have some interesting airsoft-related projects in mind, but they’re really in the larval stage right now, a little too early to say much about them.  It’ll be cool though.

My mother brought me an interesting find; what turned out to be an antique paintball marker.  A PMI/Sheridan Magnum 68, manufactured in 1988.  Missing a tank, missing a hopper, pretty filthy, but it has what turned out to be an aftermarket— and pretty hot shit —bolt.  I have it in mind to refurbish it beyond new, to fabulous! Clean it up, strip the beat paintjob, replace it with a powdercoat finish, make a new lightweight breach block that incorporates a picatinny rail instead of the old dovetail sight rail, maybe improve the grips…

Someone asked me “Man, why the f#%k does your mom keep giving you weapons?!” because, yeah, this is not the first time.  Recently she brought me a sword cobbled-together by hillbillies that we’ve come to call the ‘Compleat Rural Defendre’ (sic)…pictures to come once I work up a Diablo-style stats screen for it… And before that, she found me this beauty; A pre-1975 Crosman Mark 1 Pellet Gun, IN THE BOX, with an original tin of pellets, and a box of CO2 cartridges.  And I know it’s pre-’75 because in ’75 they removed the pressure adjustment screw and clamped it to a lower projectile velocity, because people were leaving it wide open and then complaining about crappy gas efficiency.

Links

Claudio Grassi’s YouTube channel, primarily chronicling the construction of his 1/6 scale radio-controlled 6×6 truck, with functional hydraulic power steering and air brakes…all handmade! His videos on broaching the planetary gears for his 6-wheel drive powertrain were especially enlightening.

I stumbled upon this thread about a really awesome compressed air V8 that Chuck Fellows machined.  Hella impressive! You should also check out his YouTube channel.

Sep
22

Week 38, 2013 – A Different Kind of Patent Trolling

One of my many hobbies is collecting airsoft guns.  Given that I am exceedingly poor, I have taken great interest in making airsoft guns and accessories.  Electric guns are easy, everyone knows how they work.  Gas guns are…not so easy.  I mean, the general how is fairly easy to understand, but the mechanical details and the way valves and stuff go together…  So I did a lot of digging for information, and that’s when I stumbled upon a patent, as well as the whole ‘Google Patents’ sub-site.

Once I figured out how to search right, my brain’s knack for retaining seemingly pointless trivia whether I want it to or not came in very handy.  For instance, a lot of Taiwanese and Hong Kong airsoft company names are seldom given as anything other than acronyms… But the full names— which over the years I have occasionally come across —are what’s on the patent applications.

Examples: ICS = I Chih Shivan Enterprise Co., Ltd. and HFC =  Ho Feng Industry Co., Ltd.

And of course the Japanese companies like Western Arms have all sorts of patents.  And all these applications have mechanical drawings.  Not dimensioned or anything, but I get the idea of what’s going on.

Here’s some interesting patents:
In-Magazine Pressure Reduction Valve (For 12g CO2 cartridges)
12g CO2 Cartridge Gas Gun Magazine (HFC’s patent)
ICS’s design for 40mm BB shower grenades (Not as nice as Madbull’s!)
The Firing and Rotary Magazine Assembly for ICS’s Rotary Launcher

Sep
15

Week 37, 2013 – Harbor Freight Sale

So, I made an order at Harbor Freight to get in on the Labor Day sale, and I used the main sale coupon to get 20% off the already absurd price on their Chinese knock-off ‘Porta-Band’ (Portable Band Saw), getting it for a mere $65.  I was going to get their horizontal band saw, but that would’ve been all my money, plus I found out that it wasn’t even on sale.  Then I saw the Porta-Band.  At any rate, I needed one or the other to cut stock into manageable pieces.  Especially cutting down round rod for the lathe.

I’ve only made a few test cuts with it, I’m ordering some more suitable bi-metal anti-vibration variable pitch blades from McMaster, and then I’ll probably be able to really review it next week or the week after.

I also bought their 1500-watt dual-temp heat gun, because I was really getting tired of having to lug around my SMD reflow soldering hot-air workstation just to shrink-tube something! It was 30% off at $10.

I ordered an air compressor, something I’ve desperately needed for YEARS, and it was 20% off, bringing it down to just $104…  But for some reason, they dropped it from my order and refunded the money.  It wasn’t out of stock or anything.  So now I have a compressor accessory set, an air filter, an airbrush hose…and no goddamned compressor!  What’s more, if I were to re-order it, I wouldn’t get the $25 off… I’m going to have words with them about that, but for the time being, I said screw it and decided that the $100 could be put into materials for projects in the meantime.

I found these great ear plugs at Amazon.  I’ll review them after they get a bit of use!

Sep
08

Week 36, 2013 – Holding Pattern

Nothing to report right now.  Been planning a lot of stuff, plotting out my whole operation and my idea portfolio.  Made an order at Harbor Freight, will have a little something to post next week!

Sep
01

Week 35, 2013 – The Summer of Suck

I’ve come up with this new format where I’m going to try and post a weekly status report summarizing the week’s happenings, whether I’ve posted about them or not.  That way, if there’s things I’ve uploaded pictures of to show people on IRC, but I don’t write a whole blog post about it, it still gets mentioned, and the images linked.

I’ve been sidelined pretty much since mid-June by a spate of nasty illnesses, on top of which, a visit to the eye doctor turned up that my sudden rapid decrease in eyesight is due to a degenerative condition of the cornea and can’t be corrected optically. Best. Summer. Ever.

I’m about to do a whole bunch of stuff on here to get caught up, hopefully. So stay tuned.  (I’m kind of locked into it.  I mean, I’ve got stuff goin’ on.)

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