The Shed - Engineering

Getting up to speed

11 October 2024

As sheddies, we are known to cobble together machines from whatever we have at hand. More often than not these items are less than ideal and a motor of some sort may run at a different speed to what we need. If we are looking to make a spindle moulder, belt sander, garden chipper, wind generator, compressor or similar item then it is likely that some sort of gearing will be necessary to give the right RPM at the business end.
Calculating the sizes of gears, sprockets or pulleys is a relatively simple exercise. Below is an easy reference to save having to work it out from basic principles each time.

Along for the ride

16 August 2024

Every Wednesday and Saturday morning about 20 retired tradesmen leave their lunch boxes in the Oamaru Steam and Rail smoko room, shrug themselves into their overalls, and head for the old railway workshop to get on with the day’s tasks.
They might be restoring turn-of-the-20th century railway carriages, stripping down a locomotive or installing wiring systems. Each man brings a lifetime’s worth of skills and the willingness to learn something new.
They work out of the old New Zealand Rail wagon workshop, or lifting shop as it was called, at the back of Oamaru’s historic precinct. The Oamaru Steam and Rail Society Inc took over the building in 1989. Most of the tools and equipment needed to complete the volunteers’ first major project were on hand so they rebuilt the 60mx12m workshop which had been partially demolished by NZ Rail when they decamped.

Ponoko—a cut above the rest

25 June 2024

While laser cutters are now practical for home-build projects, they are not something that everyone will want to run. They take up bench space, need care and feeding, get expensive in large calibres, and if you don’t use one that often you might well be better off letting a company like Wellington-based Ponoko cut things for you.
Ponoko stock a wide range of materials and are experienced with using their laser cutters on them. Handy, but scarcely unique given the number of engineering outfits that are out there that’ll do pretty much the same thing.

Making a kayak anchor

13 June 2024

This simple and effective rebar anchor is perfect for small boats and kayaks and is the result of welding $30-40 worth of materials. If you are a small boat and kayak enthusiast, fabricator or just want to learn some new metalwork skills, this two-hour project will be great for you; it needs few welding skills. Remember that the construction is modular and can be made to fit your needs.
With a net weight of only 7 kg, the anchor will not weigh down a boat or kayak. Anyone can pull it up, but it will still catch the seabed.

Frozen in time

7 June 2024

I just love nosing around other people’s workshops to see what they are making and what gear they have, and I’ve just had the special opportunity to look at a manufacturing workshop that was about to be sold up and, as a bonus, learn about its history.
Macdonald Refrigeration surely has a place in Auckland’s heritage as a pioneer in its field. The factory has been closed for some time now and it has been hard for the family to let go of all the gear, but it is filling a lot of valuable space.

The right stuff – part 2

2 May 2024

If you have followed our Metalworking Lathe 101 series in The Shed magazine, you will have a grasp of the basics, so here are some helpful tips to improve your lathe experience and make those projects a bit easier to do.
Quite often the material or item we need to hold in the chuck is delicate, either due to a fine finish that we do not want to put chuck jaw marks on or due to it being thin walled. For jobs with a surface finish that you need to protect it is handy to have some strips of aluminium to put between the chuck jaws and the job material. These are mostly used when holding in a 4 jaw chuck as the job will need to be “clocked up” using a dial indicator to get it running true.
The thickness of the aluminium strips cannot be relied on to be consistent as they squish up a bit with the tightening of the chuck jaws, so when using a 3 jaw chuck the auto centring effect is not so good.

The right stuff – part one

18 April 2024

These tips are a random collection of thoughts that I have grouped under the classification of things that relate to working at a bench using hand tools, rather than using a lathe, mill or other machine tool. So if you have only a workbench with some hand tools in your shed, this is meant to be useful for you too.

Metal spinning lives

12 April 2024

The exact origins of metal spinning are unknown but the craft can be dated back to ancient Egypt where examples of spun vessels have been found. Metal spinning today differs little from the past with the only real advance being that an electric motor is used to drive the chuck instead of manpower or water power.
Before the advent of power presses, metal spinning was used to make almost all round sheet metal objects such as pots, pans, lampshades and wheel rims.
The principle of metal spinning is simple: a disc of metal is clamped between the tailstock and a former or mandrel. The disc is spun and the operator then uses a lever to manually work the metal down onto the mandrel. The process helps maintain the structure of the material and does not stress it, resulting in a stronger and more stable product than if it was pressed.
While metal spinning by hand does not generally alter the thickness of the material, hydraulic-powered tools can be used to flow-form products making sections thinner where required.

Rolling stool build

4 April 2024

My wife, Rosaleen, loves to cook, and will happily spend an afternoon in the kitchen cooking meals to be frozen and given to our daughters and their friends whenever the need arises or opportunity presents.
However, arthritis makes standing in one position for long periods difficult for her. She wanted a stool for the kitchen, but ours is a galley-style layout and quite narrow. It’s wide enough for one person to walk past another working in the space, but the presence of a stool would present a major obstacle. “Why don’t you invent something?” she said.
I love a challenge like that.

Engines on the move

27 March 2024

Something that many shed owners must face at some time is how to maintain their hobby if they have to downsize their property. Owen White is one person who has successfully achieved this by not only downsizing the house but downsizing the hobby. Instead of restoring old internal combustion engines he now makes scale models of them.
In the 1960s, Owen got hold of a 1930s 9 hp Briggs and Stratton stationary engine to restore and was bitten by the vintage engine bug. It sparked a 50-year passion for old combustion engines, and for repairing, restoring and running them at vintage engine shows. Owen joined the Vintage Engine Restorers Club in 1985 after attending their third meeting and remains an active member.

Make your own backyard forge

7 March 2024

This is one of the very basic forges for heating metal bars. There are many other types of forge out there and Youtube can show you how to build and use them. My forge was made of scrap steel from my workshop and the local recycling centre.
The forge essentially consists of a fireplace or “bowl” in firebricks which are held firmly together in a brace or strap. They sit on top of a steel plate. Another steel plate sits on top of the bricks, with a large square in it to allow access to the firebowl.
A small, round, high-grade steel grate with several holes in it sits at the bottom of the brick bowl. Below this fireplace, a vertical pipe-fitting is welded into the supporting steel plate. The bottom of the pipe is an ash trap, and the ash can be dropped out by opening a small trapdoor.

Going glamping

23 November 2023

What do you do if you want a caravan but drive a Mini? You make one to fit. That’s just what Michael Wolfe of New Plymouth did – turning out a real dinky little teardrop-shaped caravan that matches his 2004 Cooper S and has all the mod cons for a decent holiday.
Michael saw pictures of little campers on the net and decided that was what he wanted – a cross between a caravan and a tent.
“I got some ideas from little caravans online and decided to go a bit more high-tech,” he says.
He built it to have the same lines, wheels and colour as his car and it looks just the part.
“I never really planned it in detail. I sketched it out originally and a lot of the construction I worked out as I went along.”

Video of Austins Foundry’s final pour

3 October 2023

This is video of a family firm that has provided a good living for at least two generations, building up an impressive skills base while manufacturing essential farm machinery for more than 90 years. The Austin family has run a foundry in Timaru for 93 years. Ken Austin, grandson of the founder, says the business has faced increasing headwinds since the Covid-19 pandemic, so he has tested the winds of change and decided to close down. The Shed visits to celebrate their technical foundry skills, the likes of which we may never see again in New Zealand.

Life in the fast lane

26 September 2023

He might describe himself as a larrikin biker, but former world motorcycle racing champion Graeme “Croz” Crosby is really more of a modern Renaissance man.
Put simply, a Renaissance man is defined as a very clever person who is good at many different things. So check the Croz record thus far: Champion motorcycle racer, commercial pilot, successful author, businessman, house builder, skilled motorcycle mechanic, enthusiastic cook, raconteur – the list goes on. He can speak a little Japanese, bake a soufflé or lace up a wire-spoked bike wheel. And even though he turns 62 this year there’s still quite a bit of the larrikin left.
It almost goes without saying that Graeme has a shed. Well, it started out as a hobby shed, somewhere to tinker with old bikes and other motorised toys. In typical Crosby fashion, though, it has become the headquarters for a thriving business restoring and exporting classic Japanese motorcycles. Graeme and his wife Helen bought a 12 acre (4.8 ha) block in the picturesque Matakana countryside an hour north of Auckland more than eight years ago, built a spectacular house, the shed and, across the road, Helen’s The Vivian art gallery.

Build a hydro power plant

15 June 2023

Ever thought of creating your own electricity? It’s a challenge a number of New Zealanders aspire to these days, as rising power prices and possible insecurity of supply bring out the Kiwi leanings towards independence and DIY.
And how to do it? A small stream, a broken washing machine, a shed and you’re away. Well almost.

Engineering