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.....

Monday, 30 December 2013

Xmas and new year update

Well, here we are at the end of one of those 'good in parts' years.  This is the usual round up of recent activities and a peep at what is coming next in 2014.

Let's start with OB's chess set.  He has shown an interest in playing chess recently, and you can't play unless you have a board and pieces to play with, so between us we knocked up a set for his birthday.  (We have a weekend in December every year when the grandkids come to stay and while Charlotte goes off shopping with the Boss, OB and I make stuff in the garage.)

I couldn't face the thought of trying to turn up 32 assorted chess men - I don't have a wood lathe, and although I can turn small stuff in the metal lathe its not something i would describe as a 'core skill'.  So instead we made a more contemporary set with all of the pieces made from square timber with various shapes hacked into the top ends - so a rook has grooves reminiscent of battlements; the bishop has a pyramid-shaped point, and the knights look like..errrr.... horses.  Pawns are plain blocks, and the kings and queens have machined alloy 'crowns' and a bit of groovage on the flanks.  Once set up it didn't take long to finish them, and although they could probably have done with another coat of danish oil, they look fine.
I made a board for myself a while back, and realised that with a bit of care I could cut precise squares on the radial arm saw (the Saw of Oblivion) by setting up an end stop and trimming the squares across both length and width.  The fine saw blade gives a clean cut, and the bits don't need any further work before sticking them to the baseboard.

The base is made from two sheets of 6mm plywood, glued back to back and at 90 degrees to each other to try to stop them from warping. A bit of careful marking out and I glued the squares on to the first quarter of the board, making sure that each piece was snug against the ones around it.  Once this part was dry, repeat for the other three quarters, then trim the edges of the whole board very carefully on the saw so that the plywood and the squares were flush.  A quick edging of beech, a bit of heavy sanding with the sanding machines and all done.

So that the pieces and the board stay together, we made a box to fit under the board.  I had some nice pieces of oak that we cut to form the sides, with the corners cut with finger joints made with a straight cutter on the dovetail jig.  Some 3mm ply for the base, a set of rubber feet, a pair of brass hinges and a ball catch to hold the lid on and we're done. Last job was final sanding and a hefty slap of danish oil applied with considerable style by OB to bring up the colour of the walnut and maple squares on the top.

Looks really good, OB is pleased with it, and it saw a very close run draw between OB and Jon on Chrismas day.  Mission accomplished.

Next up, we've been looking for a long time for a replacement for the table lamp in the hall - it has been around for ages and  doesn't really go in this house.  After exploring other options I decided to have a go at making a shoji-style wall lamp.


I've left off some of the obviously Japanese-looking details, and focussed instead on a simple structure with very slim frames - although the wooden parts are very slim, the cross-halving joints give the whole thing a surprising amount of strength and it works pretty well.
 The framework is made from cherry, and the bulb is hidden behind a sheet of hand-made paper with a very coarse texture which softens the light quite nicely.  Unfortunately it uses one of they new-fangled low energy light bulbs which give a light that is a bit too white for my liking, but it does the job OK.  I'm not too happy about the cable dangling underneath it, so I think I'll get me little hammer out and hide the wire inside the wall.

Last month I mentioned the music player I had built using a Raspberry Pi and a some software called 'music player demon' or MPD.  The Pi reads my music library off the server and pours it out of its audio port into an external amplifier, with the control of what it plays being driven by an app on any android or tablet, or iPhone. If you've ever looked at Sonos kit, that's pretty much what it does.

MPD Pi in its case
Its been running for the past couple of months, and I've tried a number of different apps to control it, and having run it for a while upstairs in the study it recently was moved to the kitchen.  Its a good measure of how easy it is to use, and how well it works, in that the Boss is happily playing some bangin' choons on it right now downstairs in the kitchen.  

The MPD software runs on the linux Pi, and can be downloaded from here.  There are several apps available, I've only tried the free ones and in my opinion the best for the iPhone is called MPoD.  For android there is a much bigger choice, my personal favourites are MPRemote and MPDroid. It works so well that I will probably cough up the cash for a couple more Pis (Pies?) and put one in the lounge and one in the study.

Last in the list of things for this month is the model engine.  Well, not built yet, but I've been doing loads of research and designing and we're about ready to start ordering materials.

I'm expecting it to take a few months to build, with a fair bit of trial and error along the way.  I've wanted to build an engine for years, and having done my share of rebuilding 'real' engines I know that there's nothing like that moment when an inanimate and slightly sulky pile of oily metal parts splutters into life for the first time and becomes a living breathing thing.

Prototype carburettor
The design will be a bit different.  Its a 2 stroke for a start, with two horizontally opposed cylinders, and because 2 strokes usually use the crankcase pressure to 'pump' the fuel/air mixture into the cylinder, this arrangement will not work as the opposed pistons cancel out the pressure.  Instead it will have a secondary pair of cylinders that will suck in the charge, compress it and then deliver it into the 'firing' cylinders for the 'bang, whoosh!' part.  I came up with this idea by accident, and only later discovered that the bloke who originally invented 2 strokes used this on his first engines.  If I think about it a bit, there's no reason why I can't use the pre-charge cylinders to act as a supercharger.

... and seen from the other end
It will also be quite big, because making something as complex at really small scale is very difficult with my chubby fingers, so the capacity will be about 12cc, and the overall dimensions around 140 x 80 x 60mm.  I could machine all the parts from solid chunks of metal, but that is an expensive way to produce a floor full of swarf so I plan to try my hand at casting some aluminium.  I reckon I can build a simple furnace with a couple of clay flower pots, a hair drier and some charcoal bricks, and I can make the patterns for the castings from sand-packed styrofoam which vanishes in a puff of smoke and flame when confronted with boiling aluminium.  

So how far have I got?  Designs are finished enough to make a start on hacking up some metal, and I have made a simple carburettor (probably the most complex part of the lot) out of alloy bar and brass just to prove that the design works - tested it by putting the fuel feed pipe in a jar of water and blasting compressed air through it, producing a very satisfying mist spray out of the other end when at full throttle, though it took a while to mop up the puddles afterwards.  I've made some patterns for the 'real' carburettor and am about to start on the ones for the crankcase and the various manifolds before getting to grips with building the furnace.  Woohoo, can't wait.

I also am pleased to report that the tradition of making things from bits of junk appears to be hereditary with Sean's recent completion of a gyro-controlled camera mount.  Works a treat, as seen here in use on a bike, and an earlier version with a few glitches here on the back of the motor bike - we should call this one 'buttock-cam'.  Great job, and all based on a couple of bits of scrap aluminium hammered into shape in my workshop a few weeks ago.

A quick medical update as well.  I finished the radiotherapy mid-November, and as expected the major lethargy from that has taken a while to wear off.  I'm feeling almost back to full working order now and planning a new fitness regime starting this week with a view to getting back into shape and removing the flab round my middle (caused mostly by the hormone treatment, but not helped by my not training since April)  and getting back into TKD training by the end of January all being well.  Next steps are a follow up with the prostate team next week, and another with the haematologist at the end of January, fingers crossed but I'm not expecting any significant things from either of those two events.

An what of 2014, I hear you cry?  Well, the main tasks are going to be building the engine, and getting the kart ready for a full season's racing with a determination to come somewhere other than last.  I also have a coffee table to make for Sean and Mad, and OB has an arduino now, so probably a good deal of telephone and on-site support will be needed for that.  Having started the model engine work, I've also been looking at the design of the very old Commer TS3 engine, made by Commer trucks in the UK in the 60's and discontinued by them when Chrysler bought the company.  This engine was a supercharged three cylinder, opposed piston two stroke diesel with a distinctive exhaust sound, and I rather fancy making a working model version of one after the first engine is up and running.  The old timers among you may remember these engines, they had a nasty habit of kicking back and running in reverse with rapidly increasing revs and an inevitable very messy and noisy end - I once saw a driver  leap from the cab of his truck and leg it away from the vehicle at amazing speed just before the engine burst, filling both the cab and the roadway with oil, smoke, and bits of very hot metal.  I'll try to avoid that fate if I build one :-)

Onward and upward.  Time to order some metal and locate a couple of flower pots for the furnace, I promise lots of pictures for next month.