About Me

I've been taking things to bits, and making things ever since I can remember, starting with dismantling knackered alarm clocks and watches and helping my dad fix the car. Now I have a well-equipped workshop and have aquired lots of new skills, so I can make better stuff. When they first appeared, I became involved with personal computers, and these and developments in electronics have increased the scope of the things that I can do. Just recently retired, so O yes, now I can make all sorts of stuff.....

Tuesday, 11 February 2014

First post of 2014 woohoo!

Well here we are again, another new year and another round of posts, hopefully monthly as usual.  A bit late in starting as Mr Google decided to change the blogger interface so you now need to get a spade out to dig for the information that lets you post a new entry - why? National security?

Anyhoo, some good stuff going on already this year, so lets get started.  First up, a couple of WTF?? things.  

The 2013 Harley Davidson Super Glide Custom A 1,585cc Harley-Davidson Dyna Super Glide, donated to Pope Francis last year and signed by him on its tank, is displayed ahead of Bonham's sale of vintage and classic cars, at the Grand Palais in Paris, Wednesday, Feb. 5, 2014.First is the announcement a couple of weeks ago that the Pope was going to auction off a Harley Davidson motor bike for charity.  He was given the bike to celebrate the H-D centenary and he graciously signed the fuel tank before letting it go for sale.  Raised a load of dosh for good causes and therefore a Good Thing.  My question is: what in the name of Mother Teresa were H-D thinking when they gave him the bike - its not an obvious marketing thing (not many Hell's Angels look up to the Pope after all), and the image of his Popeness tearing along the autostrada clutching his skull cap and with his white silk robes blowing up over his head is one that I'd prefer to forget.

The second news item is a Well Done!!! to the bloke who arrested Tony Blair in a posh restaurant a couple of weeks ago.  Apparently the bloke in question was a barman at the eatery and when he spied Our Tony shovelling expensive nosh into his face he trundled over and attempted a citizen's arrest (which he is quite entitled to do) for the crime of getting the UK into what some perceive as illegal war in Iraq.  To be fair, Tony did a good job of dodging and weaving and managed to avoid being dragged off to the local nick, but I imagine that his bodyguards were a bit flummoxed - they are supposed to protect him, but if the perp is a righteous citizen carrying out a legal arrest they're a bit banjaxed.  Anyway, 10 out of 10 to the barman whose name is Twiggy Garcia and who quit his job immediately after.  Not all bad for ol' Twiggy though, as there is a running bounty payable to any potential arrestors and Twiggy picked up two grand from them for his efforts.  A good result all round, except that Tony is still walking the streets instead of sharing a damp cell with a man named Bubba.  Check out the story here

On to other things, and the first of these is the engine.  I've managed to get quite a bit done on this over the past month or so.  I was originally going to make a twin cylinder engine, but part way through making the first parts I realised that because I had no idea if the thing would start and run, making a double lot of parts for what might end up as an inert lump of metal was a bit of a waste of time.  Instead, the design has changed to be a single cylinder jobbie, but keeping the pre-charge cylinder arrangement.

So far, I've made the following:

- Cylinders, liners and heads for both the pre-charge and firing cylinders
- The crankshaft and con-rods, with bronze bushes for the big and little ends
- A pair of pistons, complete with two cast iron rings each and pressed-in wrist pins
- The gear set to drive the oil pump off the blunt end of the crankshaft, pump gears are under construction now

Firing cylinder, head and piston
The cylinders are cast iron, with an aluminium jacket machined from bar and pressed on to the cylinders, and the inlet and exhaust ports machined through both metals.  Making the jacket from alloy was pretty tedious, as it takes ages to bore out and wastes a ton of material.  Not only that, but machining flats on the outside to attach the manifolds is not the strongest way to do this, so for the next version I will cast the jacket with manifold ports cast in.  The heads are just machined from bar.

The crank is made in several parts - two steel end pieces machined from bar and each pressed hard into a circular web plate, and the big end journal pressed in good and hard to both webs once the conrods have been fitted.  Not finished this bit yet, as I need to make a jig for the pressing together part to ensure that the two halves of the shaft are dead in line or the engine will run like a 1956 BSA.

Crank halves; conrod blanks, piston and cylinders
The pistons were a challenge, because they need a slot machined inside for the conrod to flop about, plus a very central hole for the gudgeon pin.  As if that isn't enough, the piston rings are minute - cross section is 1 mm x 1mm - and very fragile, so we have a small pile of broken ones.  Lucky I made a few spares :-).  I made the rings by machining a cast iron cylinder, lapping the outside and then parting the rings off .  Careful polishing of the faces so that the ring fits the groove properly, then split each one with a cutting disc in the Dremel and trim the ends of the split carefully to give the required 0.004" gap when the ring is placed loose in the bore.  To cap it all, the rings need to be stopped from rotating, as if the ends coincide with one of the ports the ring will snap and cause some serious grief.  The only way to stop them turning is to drill the piston with a 1mm diameter hole, press in a pin and grind it down to leave around 0.3 of a mm sticking out into the groove.  Then file a recess in the back edge of the ring around 0.5mm deep and hope it doesn't bind when it finally gets assembled.  Fat fingers are NOT an asset here.

Oil pump drive train plus one of the brass pump gears and its bearings
Although this will be a 2 stroke, I'm keen for it not to run in the traditional cloud of blue smoke - this is part of the rationale behind the pre-charge cylinder, because this will not need oil mixed with the fuel for lubrication.  However, there needs to be some way of oiling the crank, pistons and other whirly bits, so she's going to have a proper gear oil pump with a wet sump.  The drive for this will come off the blunt end of the crankshaft, through a train of gears that reduce the speed of the pump (since apparently slower pumps of this type work better than faster ones).  I made a whole bunch of gears for the Magic Clock a few months back, so making these was pretty straightforward although a 60 tooth gear takes around an hour to machine, one tooth at a time.

Trial assembled whirly bits
Once the gears are finished the only easy bits left to make are the flywheel and the manifolds.  I'm not sure how big and/or heavy to make the flywheel yet, and it will need some means of starting to be built in as well - I'm planning to use a cordless drill to spin it over, not sure how yet.

The last adventure will be the casting of the crankcase.  This will need to be split in two halves to allow the oily bits to be assembled, and it will have a pair of end plates which will carry the ball bearings for the crank as well as the oil pump and gear drive.  I  plan to melt the alloy in a tin can, heated to red heat in a ceramic flower pot full of charcoal and retained in a metal paint can with a hair drier blasting air up through the charcoal to give it mucho hotness.  I have all the parts except the metal paint can, so I'm checking all the builder's skips that I come across in the hopes of recycling one.  I've already made the patterns for each part out of styrofoam, and I plan to coat each one in a plaster mix before packing them in sand and pouring cellulose thinners in to melt the foam and leave the cavity in the sand behind.  It may not work, but at least I can keep re-cycling the mistakes until I get it right.

Almost last, the airbrush has seen some more active service with some decoration on the side pods of the kart.  Plain black is not a good racing look, so I played around with a variety of different ideas but soon realised that the water-based acrylic pains that I have are just not intense enough in colour.  I need to play with the proper solvent-based ones, but as these run at around a tenner per pot I'm reluctant to shell out for these.  Instead, I opted to paint something which doesn't need a strong colour, and the answer is FLAMES!.  I doubt that they will survive the first race, but I had a lot of fun painting them

And finally:  the Tourette's Parrot.  We were at the pub a couple of weeks ago and the landlord Graham had a fine green parrot climbing all over him.  I admired the bird, as you do, and asked how he came by it and he said that he rescued it.  It turns out that the bird can talk really well, but hates children - so much so that it launches into the foulest language imaginable every time it sees one, and since the previous owners were expecting their second child they were understandably keen to offload the foul-mouthed critter.  Most Excellent, havn't laughed so much in ages.

Next month we should have a full report on the alloy casting adventure, plus I need to fit a new towbar on the Boss's new car before the first race in mid March. Oh, and the Magic Clock has lost one of its LEDs, so I need to fix that