In November 2011, someone very kindly lent me a Clarke CL300M, a small benchtop metal-working lathe, generally known as a “mini-lathe”. This blog is to document my experiences as I get to know it and, hopefully, develop some machine-shop skills. From lathe novice to… we’ll see!
Metal swarf, fumes and whirring things with sharp edges are all largely incompatible with tiny infants. As is spare money. And spare time. And sleep. However, an inveterate tinkerer needs to tinker, and I’ve been beguiled by the siren-song of miniature aviation…
Happily, it turns out that toddlers can be entertained by flying models. Now, flying models do tend to have whirring things with sharp edges, but that’s why the good Lord gave us quick reflexes and the ability to shout “nooooo!” in such a way as to cause temporary paralysis in three-year-olds. And also kill switches on our transmitters.
It further transpires that model ’planes are surprisingly hard to fly properly. Trickier than real ones, I think. The little ’un now thinks that “crash” is a synonym for “land” (also “bugger”, “argh!”, etc.) – something we’re going to need to clear up before taking him on any more commercial flights.
Back in the day, if you wanted to fly model aeroplanes, the deal was you spent every evening all winter gluing and pinning balsa wood and inhaling a range of allergens and cellulose thinners, and then the first dry day of spring, after faffing about with nitromethane, risking eardrums and fingertips to get your little engine going, you watched your masterpiece experience some serious accelerated entropy as you failed to take account of ground-effect wind-shear on finals or were imprudent with the centre of gravity or something. Then you blamed the expensive but shonky radio gear and started accumulating Plans and balsa for the next season.
This sort of thing is incompatible with toddlers unless you have a very traditional “other half” who is happy to be left holding, changing, feeding, clothing and generally dealing with the baby full-time. Or a team of nannies, if you’re posh.
Sixty five quid to you, guv. Photo (c) HobbyKing.
These days, though, we have superb radio gear that costs next to nothing and is far too effective and reliable plausibly to be blamed for destroying models (though people still try…) and we have Foamies (model planes made of the kind of stuff that was originally intended to protect other stuff from severe impacts,) and we have RTF (“Ready To Fly”) and we have ARTF (“Almost Ready To Fly”) and we have fuss-free and very effective electric power options. Basically, you can now substitute a bit of cash for an entire winter spent inhaling dangerous substances and getting divorced. And, with Foamies, you can get the hang of flying models a lot quicker, because Foamies are often good for multiple attempts at landing.
So, one of my recent-ish acquisitions is a surprisingly cheap one metre wingspan model Pitts Special biplane, made of some kind of foam. Among the many economies embraced in the design of this “VNRTF” model is a propeller attachment that is, frankly, rubbish. The thing’s powered by a 12v-ish lithium-ion battery driving an electric motor, which has ample power and very surprising duration (over ten minutes from a mere 1300mAh). The motor has a long 4mm diameter shaft with an M4 thread along all but about 2mm of its length. The manufacturer has optimistically furnished it with a pair of ordinary-sized M4 nuts and a small washer by way of a seating for the propeller. The prop is 10 inches in diameter, and it clears the ground by approximately 3/5 of bugger-all, especially when the ’plane’s taxiing up on its main wheels with the tail in the air. So when the prop blades strike a small tussock of grass or moss or a conveniently placed half-brick, the prop is wrenched around and the nuts dig in to the prop hub and it then runs massively out of true with a tremendous vibration and much loss of power. No amount of messing about with spanners and rulers will get it to run true thereafter, there’s simply not enough seat area on the side of an M4 nut, or even a normal M4 washer, to keep a propeller hub decently aligned.
So I lifted the dust cover on the lathe, and peered beneath. It’s still there. Watch this space…
So, I’ve been a bit quiet on here for “a while”. This one tends to absorb around 150% of all available time… Still, every child needs, I dunno, something steam powered or somesuch, I feel.
P.S. yes that’s a bit of a dialogue box bottom left, it’s just a screen grab, sometime I might have the time to do a proper export, right now he’s eating the curtains and climbing up the power cable…
Powerful lobbying groups want to censor and destroy the Internet via astonishingly ill-conceived and broad legislation in the U.S.
Large chunks of the Internet are voluntarily blacking out all or some of their content in protest, for 24 hours, today (Weds 18th Jan, 2012). I support this action. I would urge anyone to phone political representatives, boycott MPAA members’ products and services, and whatever else it takes to get this ridiculous legislation cast aside. From the printing press onwards, there have been people striving to stifle progress and creativity – these people don’t just oppose the illegal copying of commercial “content”, they really, really don’t want you or I generating and consuming content that they get no revenue from. It’s pretty much as simple as that.
I decided that I couldn’t get by without a dial gauge, and wasn’t up to making one (I did contemplate it…). However, RDG tools have ’em for very little money, so I ordered a metric DTI and a magnetic base via their ebay shop, for an all-in price of significantly less than thirty quid, with free postage. Delivery was by DPD, and pretty much next day, the DTI and base seem solid and entirely respectable quality, so RDG tools get a big thumbs up, definitely be shopping there again.
I hesitate to call it “milling”. I made a cutter to deepen the magnet hole on my spindle extension, trying it out on a spare bit of brass first. Could have been better, but given that I wanted roughness for the epoxy to key into, it did the job.
In which I make a tool, curse brass, do a bit of boring, create an internal metric thread and eventually retire the faithful cork in the end of the spindle. My second thing! (Well, third if you count the tooling).
Here it is! My First Thing! I dunno what it is, but it’s lovely! After fiddling around working out gear ratios for thread cutting, I was desperate to give it a go, and it worked out reasonably well. Conclusion: cutting threads on a lathe might take some practice… who’d have thought?
Microphone holders, especially American ones, tend to have a 5/8″ 27tpi (turns per inch) thread. I have no idea where to buy a tap or die to cut that. Threadcutting on the lathe, though, looked like a good exercise. I reckoned I could do the M12 threads I wanted, too. In fact, I may never have to buy another tap or die! I read up on how to do it, went to the lathe to practice, and hit a slight snag…
An oft-cited design flaw in these mini-lathes is the way that the hollow spindle ends inside the gear cover. Any swarf which trundles along inside the spindle will drop down into the (nylon) change gears, whereupon bad things ensue. Various folk have addressed this with nicely made spindle extensions, like this one, and I fully intend to do likewise. Meanwhile, however, there’s a very quick and easy interim fix. I can recommend something like Lagunilla’s 2002 temperanillo, on half-price offer from Somerfield – entirely acceptable wine, easy on the palate and easier again on the wallet, and the cork fits just perfectly in the end of the spindle.
After the tedium of de-rusting lathe ancilliaries, I was keen to play with my new toy as soon as possible. To this end I plonked it on the only available surface which seemed kind-of suitable, a cheap copy of the “leading brand” folding trestle-type workbench-cum-woodworking-vice, of the sort favoured by D.I.Y.-ers on a budget. However, it wasn’t long before I was mentally designing, then building, something more purpose-made.
 | lathenovice on It’s been a while… |
 | Geoffrey Fairhurst on It’s been a while… |
| lathenovice on Gears |
 | gadjet on Gears |
| lathenovice on Gears |
