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From scrap metal to cooking spit

It’s not my original idea. I used to live in Tutukaka and we’d go on 4WD rallies and claybird shoots in the backblocks where there was no power. It was a lot of fun. One time a guy turned up with a battery-driven spit and the idea stayed in my mind. You could take it where there was no power – I always said I would design something one day that worked with no power.

Using scrap pipe and wheels, sheddie John Stick turned out a respectable spit for those backyard feasts
By Terry Snow
Photographs Gerald Shacklock and Jude Woodside

Over 10 years ago, The Shed magazine brought you Robin Overall’s outdoor pizza oven which lit up those balmy evening get-togethers. Now, we thought you might like to try building a backyard spit.
While your guests marvel at what a couple of pipes, bicycle wheels, chains and a windscreen wiper motor can do, your spit can be cooking lamb, a sheep, pig or chickens to a turn. You will be the toast of the summer gathering.
Electrician and sheddie John Stick came up with the project which he emphasises is a real scrapyard challenge. He tells the story of his project.
“It’s not my original idea. I used to live in Tutukaka and we’d go on 4WD rallies and claybird shoots in the backblocks where there was no power. It was a lot of fun. One time a guy turned up with a battery-driven spit and the idea stayed in my mind. You could take it where there was no power – I always said I would design something one day that worked with no power.
Nothing in this project cost money. All of the spit is from salvaged material, not that I go round the streets on inorganic rubbish collection day. To turn the spit I have a little motor from a car windscreen wiper. I’ve also used water pipes and bits of bikes, the chain, crank wheel and so on. Even the screws I used to attach things were just what was available.
When we take the portable spit onto the site of our ten-acre block, I sometimes attach it to the tractor battery to power it up. I’ve used a wiper motor because you don’t need a lot of power. For cooking a whole sheep or pig on the spit, you need the battery to go for half a day. You could run this off a 12-volt battery or a gel battery.
Cooking time depends on the size of the meat. For those longer jobs, I always recommend that as well as the battery you’re using, you have a stand-by battery.
I couldn’t tell you how many hours I took to make the spit because I did it as and when I had time. I just made the whole thing up as I went along. I do something and then ask what do I need to do next, especially when using salvaged materials. No two things are the same. The first version of anything is usually a prototype – you can always improve the model.

Wiper motor
Different windscreen wiper motors have different methods of propulsion. The critical piece is the rotating arm on the motor. To run the spit at a gentle pace, this rotation is slowed by bicycle gear reduction, from the chain that runs from a small wheel to a big wheel which everyone understands.
I have timed this spit at seven turns a minute. That’s slightly fast. I would prefer three turns a minute and would get a better reduction by using a bigger chain sprocket at the top. The plate I designed and mounted on the driving arm of the windscreen wiper motor has nothing standard about its dimensions. It will depend on the size of the bicycle driving cog which is attached. I have used a driving cog from a standard bike, a ten-speed I think. It’s what got tossed away. I simply cut the plate to fit, and this one is 50mm x 40mm.

Mounted plate
Then I put the motor on a larger plate. This motor mounting-plate is scrap steel 220mm long x 65mm wide. Everything is scrap. To this, I fixed another, smaller piece of steel for screwing on a bigger front chainwheel from a bicycle. This wheel came from a BMX cycle which I pulled apart and found a way to mount on the shaft, keeping the bike’s bearings. I just had to accommodate three moving parts.
I put the lower chain on. It doesn’t have to be under great tension when the screws go in because they hold it. I put one screw in from the front and the other two from the back of the small holding plate because of easier access.
The biggest gear wheel at the bottom has a smaller chain sprocket fixed to it. A chain leads from this small sprocket to the driving wheel on the top pipe.
The next step is to attach the motor to the up-stand. The motor mounting-plate is bolted to the stand at one end but floats free at the other end of the mount. The chain to the wheel on the turning rod is tensioned simply by the weight of the motor assembly.
The top wheel is arranged so it lines up. The way the driving assembly is screwed together is to do with the height of the wheel and to do with the chain tension.
That is the driving assembly essentially. I made the hole in the pipe for the motor mounting-plate with a thread on entry and the exit.

Pipe assembly
There are only two diameters of pipe involved in the spit, 27mm outside diameter (OD) for the driving pipes, and 34mm OD pipe, skimmed out to depth required, for the centre pole of the feet.
The driven-end of the turning pipe I had to make simple. I welded a front chainwheel I had off a kids’ BMX bike onto a small section of pipe. This sits inside another piece of pipe that was skimmed out. I made a small hole in this for oil lubrication.
As part of the small amount of lathe work in this spit, I spun the pipe where it runs inside the shaft. It took 10 minutes on the lathe to make this pipe fit. It is welded onto the sprocket. A local turner or engineering place could do it for you. I then welded the hollowed-out pipe to another piece of pipe in an upright T-shape, fitting that inside a sleeve that I slipped over the up-stand and screwed in place.
A hole at the end of the small driving wheel pipe is used to wire on the main pipe length that holds the meat. The other end of the pipe that holds the meat rests simply in a half-pipe that is hollowed out and welded onto a section of pipe that slips over the far up-stand. The spit is made so you can rip it apart and stick it on the back of a truck, that’s why there’s just a piece of copper wire holding the main pipe to the driving pipe.
The up-stands are galvanized water pipe, 27mm OD and 540mm long, with holes in the columns for height adjustment.

I didn’t know what the feet would be – I had the up-stands in a block of wood to test the principle first before making the metal feet. I made transportable tripods so they have folding legs, rounded off so they don’t catch in the car, clothes etc. I used standard 30mm angle iron for stand. The legs are 25mm angle iron at an angle of 120°. On a piece of card and with a protractor with I drew the legs at 120° and from this made vertical marks on the metal with engineer’s chalk for angle. It’s hard to hold onto the leg while getting the tack on. The legs are the same for each end. The up-stand pipes have holes in them for height adjustment.

Main pipe
The pipe that holds the meat should be long enough to accommodate a side of sheep or pig that you’ll want to cook. Again, I made it from galvanized water pipe, but you could use stainless steel or anything you had to hand. I cut small sections of pipe to slip over as little sleeves. Spikes are welded on to these sleeves. I threaded a couple of bolt holes into each sleeve so I can bolt them onto the pipe where they holds the meat.
The meat can be whatever you want – ham, half sheep, pig, chickens,- but it shouldn’t be huge. Use your common sense. The spikes are adjustable. When the animal is wired to spikes, it’s important to be sure it is balanced, so it doesn’t tip around with the pipe with a big swing because there’s more weight on one side than the other.

It’s a good idea to use a tin shield to protect the motor from the heat under the animal. For coals, I put the fire to one side rather than underneath as some people have it. You have a sheet of iron under the spit, and simply spoon hot coals onto it from the fire next to the spit. I have also had a cut-off drum under the meat. In that I burned very thin chips of hardwood from a railway sleeper. Ti tree would be perfect. You need to keep it in chips to keep the heat low. Low and slow is the answer. When we cooked the sheep at the bach, as shown in the photos, it took about seven hours.
In this case, I connected a switch to the battery so I could control the turning meat, leaving it stopped to cook the thicker parts for a minute or so from time to time.”


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