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Homemade calipers are helpful when turning bowls

homemade calipers

Getting the wall of a bowl the right thickness is very important. The wall doesn’t have to be the same thickness all the way down, but it must look and feel right. An experienced turner would likely rely entirely on their sense of touch and not use calipers at all. But simple, non-adjustable homemade calipers can help. They are quick to make and use. Calipers are normally adjustable, and made of steel. But adjustability is only necessary if you actually need to measure the thickness. I find that when using ordinary steel calipers to check the wall of a bowl, I set them to more than the thickness anyway. By watching the gap between the point and the wall, I can see that the thickness is right. I made a batch of fixed ones to help with the teaching I do.

Material for homemade calipers

I used scraps of 6 mm MDF. This is unlikely to scratch the finished surface of a bowl, which plywood might. But with care in use, other materials would be fine. Dimensions are not at all critical, as long as the central cut-out is big enough for the caliper arms to reach down to the bottom of the bowl. They could be made in any size.

Making the calipers

I cut the blank to a circle with a band saw and drilled a small hole in the middle for the revolving centre. I then pinned the disc to the jaws of a chuck with the tailstock. This is a very quick method of mounting discs in the lathe. Friction from the chuck jaws drives them. I trued up the edge of the disc. Turning MDF is dusty, but very easy with a scraper. Then I marked an off-centre circle and cut the middle out with the band saw. The entry cut is at the narrowest point. I sanded the inner curve with a drum sander, but this, like the turning, is purely for appearance. Hand sanding, or no sanding, would work just as well.

Then I enlarged the entry cut and sanded the ends of the arms. Although these calipers have no adjustment, it would be easy enough to cut them in half and drill for a bolt and wing nut. The gap should be a little more than the likely wall thickness, say 15 mm for walls of 12 mm. When one arm slides down the inside wall, the gap between the other arm and the outside of the bowl clearly shows changes in thickness. I drilled a small hole for hanging the caliper on a nail.

 

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Homemade faceplate rings

Faceplate rings are useful in bowl making, and also as a quick method of mounting things such as sanding discs in the lathe. They allow you to work on a batch of items over a period without having to remove the fixing. I needed a number of them, and now have a batch of homemade faceplate rings. They are a good alternative to a screwchuck

Making the rings

Instead of the usual steel or light alloy, I made my homemade faceplate rings from good quality birch plywood, free of voids. They are about 100 mm across and 12 mm thick, but other sizes would work. After bandsawing the blanks, I marked the centres and pinned each one against the open jaws of a chuck with the tail centre. This is a quick and easy method of driving small items by friction. I turned the rims true, then gripped the discs by their rims in the chuck. For this I used an engineering chuck, but could have made a jam chuck from scrap wood. I used a small skew chisel to bore a tapered hole right through each one.

Just as when making a chucking recess in a bowl, the holes need to fit the jaws of the chuck that will hold the rings. The diameter should fit the jaws when they are almost closed. The taper should match that of the jaws reasonably closely.

I then mounted each ring in the chuck it was intended for and marked a circle on it. My lathe has an indexing ring, so I used that to divide the circle into thirds for the screw holes. Without that, I could have used a strut under the chuck jaws to locate the holes for the screws. I drilled the holes to suit the fixing screws. They have a countersink on one side for the screw head, and on the other to accommodate swelling in the timber made by the screws when in use.

Durability of homemade faceplate rings

I was slightly concerned that the expanding chuck jaws could cause the ply to de-laminate in use. However, the screws prevent the layers from separating. I put the screw holes fairly close to the recess, where the stress would be greatest. Wooden rings cannot be as strong as steel, but these are holding up well. They should be at least as strong as the chuck recess made in a wooden bowl.

With an offcut of plywood and a little time, I have a number of very useful homemade faceplate rings, saving the significant cost of factory-made ones.

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Homemade tools for woodturning

Woodturners need cutting tools.  In past times, they made their own tools, or went to the local blacksmith. Most people now buy their kit ready-made. But homemade tools are still useful. Some turners still make their own tools. They do it to save money, or because they need a special purpose tool that cannot be bought. Some do it because they enjoy the tool making as much as they do the turning.
I enjoy toolmaking, though I have to admit I don’t pay enough attention to the look of the finished results. I hesitated before posting photos on this page. None of my homemade tools will win a prize in a beauty contest. But they all work, and among the tools I use quite often, about half are either homemade or modified in some way.
Homemade tools for woodturning fall into three main groups:
  1. gouges
  2. scrapers and chisels (flat tools)
  3. tipped tools

Homemade Tools – equipment and materials

Making tools needs some basic metal working equipment, such as a file, a hacksaw, a few threading taps, a grinder and a bench drill. Simple forging needs a makeshift anvil, vice, pliers and a hammer, and a source of heat such as a charcoal fire or a blowtorch. See my post on hardening and tempering steel for details.
Gouges and flat tools can be made from high carbon steel. This is now rarely used for commercial turning tools, apart from cheap starter sets. High speed steel has almost completely replaced carbon steel.
High carbon steel was known as tool steel, and once was the only choice for making tools. Carbon steel tools can take a very good cutting edge. They can do just about anything that modern high speed steel tools can do. But they are less resistant to abrasive wood, so need frequent sharpening. And they lose their temper easily with heat. So they need more care when grinding, and lathe speeds must be lower.
Tipped tools are usually scrapers, the tips being HSS or tungsten carbide.
Carbon steel, though rarely used for woodturning tools, is still widely used for other purposes. You can buy it, for example as silver steel, or find it as scrap. You can make cutting tools from old files, springs, motor parts and all sorts of other scrap. I have used the tines of a garden fork, the rings of ball races and screwdrivers and chisels.
Files are carbon steel. It was once common practice to make them into very effective scrapers and chisels, but there is a potential problem. The grooves between the teeth of the file can start cracks in the steel. Though I have not known it to happen myself, this could lead to the blade breaking under stress, which would be dangerous. If you choose to make scrapers from files, you should use only thick, heavy, fine-toothed ones. Grind away all the teeth and grooves and check carefully for any visible cracks. Then thoroughly anneal the tool, re-hardening and tempering just the tip.
A scraper made like this is unlikely to break in normal use. But you should not put it under severe stress, for example from heavy, intermittent cutting on an uneven blank. A bad dig-in could also break a weak tool. This problem can also affect corroded steel. So it is safer to buy commercial scrapers for woodturning, or use only sound, bright and thick steel if you want to make tools for heavy work (or think they might get used in this way at some future date).
You can use HSS tool bits to make gouges and all sorts of scraping tools. You just secure them in a holder that is usually made of mild steel or unhardened carbon steel. Some tool bits are long enough to fit into a wooden handle directly.
Tungsten carbide tips are becoming more widely used in woodturning. Not all grades of carbide are suitable however. Most tips available are for metal turning and cannot be made sharp enough for woodturning. But you can use tips of the proper grade of carbide to make scrapers that perform very well.
Homemade gouge converted to beading tool
A homemade gouge ground as a beading tool

Gouges

These at first sight may seem difficult to make. But there are several ways to make the flute of a gouge:
  • Forge the flute. It needs some skill to get an even flute, and more equipment, such as swages to form the shape. Good fun to do if you have the facilities.
  • Grind the flute. Make a small gouge by grinding or filing a flat on a carbon steel rod (such as a heavy screwdriver), then using the edge of a small grinding disc to form a groove. The flute does not have to be full length – 15-20 mm long will function perfectly well. You can use this method with high speed steel or hardened carbon steel.
  • Drill the flute. Use a twist bit to drill into the end of a carbon steel rod, making a hole at least 20 mm deep. Then just file or grind away half the hole, leaving a groove. This is the easiest method and gives a uniform semi-circular flute. The internal surface will benefit from light grinding or polishing to reduce the minor scratches left by the drill. Even better is to drill very slightly under size then use a reamer to clean up the hole. You must anneal the rod before drilling, grind the bevel, then harden and temper it later. I’ve made several of these drilled gouges in various sizes, and use them often. They are all small, but the method would work for larger gouges too. Ready-made small spindle gouges are often too thin and flexible for safe use.
small homemade spindle gouge
Small homemade spindle gouge with drilled flute of about 2.5 mm

 

small homemade detail gouge
Small homemade spindle detail gouge

 Scrapers

These are very simple to make. All sorts of scrap are suitable. You just have to grind a carbon steel bar to shape, harden and temper it correctly, and fit it with a handle. A long and thick HSS tool bit will fit directly into a wooden handle and make an excellent scraper. You can make chisels in the same way.
homemade square chisel
Homemade 45 mm square chisel made from a vehicle leaf spring
hollowing tool made from garden fork tine
Homemade hollowing tool made from fork tine
This tool was hot forged, in the same way that I made this hook wrench. I hardened and tempered its tip.

Homemade tools with HSS or carbide tips

These tools are also very easy to make. You just have to adapt a steel bar of suitable size to take the cutting bit, either of high speed steel or tungsten carbide. It’s easy to hot forge the bar into a curve to make hollowing tools.
You can buy square or round HSS  tool bits from Ebay. All that is necessary is to drill a hole in the end of the steel bar with one or more tapped cross holes for grub screws that will hold the HSS securely in place. More simply, you can just glue the bit into the hole. Heat will release it later if necessary.
You can silver-solder or braze flat section HSS tool bits to the top of the bar, with or without making a step for them. I used this method to make a ‘fluteless gouge’.
Tungsten carbide cutting bits usually go on top of the steel bar, with a single locking screw through the bit into a tapped hole in the bar.
I made the lower of the two scrapers shown below from a solid carbide burr and shaped it with a diamond burr in a Dremel tool.
Homemade carbide tipped scrapers
Carbide tipped scrapers

Graver

This is a tool like a woodturners’ point tool, with three flats ground on a round bar, in this case of high speed steel. You use a graver for turning mild steel freehand. See my post on turning metal in a wood lathe for details. Gravers work on wood too. You can make a graver from square bar by grinding a single diamond-shaped flat from one corner to the one diagonally opposite, at an angle. This gives two cutting edges.
homemade graver for metal turning
Homemade graver made from round HSS

Safety

Please pay attention to safety when using homemade tools. There can be risks if you exceed their safe limits. Don’t use homemade tools if you are an inexperienced turner because you may not recognise these limits. If you can’t rely on your own judgement, don’t try it!
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Homemade compasses, any size you like

Here is a useful tool for turners – a giant pair of homemade compasses. When preparing large bowl blanks the usual commercial compasses may be too small. I made a large pair from scrap wood. Opened to 90 degrees, they can make a circle of 800 mm radius. You could make them any size you like.
My pair has arms about 550 mm long, made of planed scrap softwood. They are joined at the top by a small coach bolt, washer and wingnut. One arm has a pointed nail inserted, the other has a simple clamp to hold a pencil. Drill the hole for the coach bolt the same diameter as the bolt. The square part of the shank will pull into the hole when you tighten the wingnut, and stop the bolt turning.

The point

To insert the nail, drill a small hole in the end of the arm. The hole should be just a little less in diameter than the nail, to make it secure without splitting the wood. Cut off the head of the nail and grip it point down in a vise, then tap the arm down onto the blunt end. Cut the arm to a blunt point so the corners don’t get in the way.

The pencil clamp

To make the pencil clamp, drill a hole for the pencil first, making it a sliding fit. I shaped the end of the pencil arm a bit, but that isn’t essential. I just thought it would look better that way. But a blind hole for the pencil might make it less convenient to adjust. Then drill a cross hole, close to the pencil hole but not intersecting it. Now make a saw cut to split the pencil hole down its middle. Go a bit past the cross hole so there is some spring in the wood. Fit a small coach bolt, washer and wingnut in the cross hole. When tightened, it will close the saw cut and pinch the pencil to stop it moving.
Smooth off any rough edges, drill a hole through both arms near the pivot so you can hang it up, sharpen the pencil, and your homemade compasses are finished.
pair of large homemade compasses
Large pair of homemade compasses

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Tapping a thread in steel is a useful workshop skill

This post is for people with little experience of working in metal. Tapping a thread is a useful workshop skill. It’s easy to cut threads in steel with a tap. You can use a drill and tap to fit a cutting bit to a tool shaft, assemble steel parts, or to make up frames for tool stands etc.

Drill the hole

Drill the hole for the thread using a tapping drill. This is just a normal twist bit the correct size for the particular thread. When drilling holes in steel, you need a bench drill with the speed set slow. This makes a hole that is square to the surface of the metal. When drilling metal like this it is essential to use a vice or clamp. The drill can catch when it cuts through, spinning the metal round and doing your hand no good at all.

The size tolerance is small, and accuracy is important. If the hole is bigger than recommended, the thread will be weaker, though the tapping will be easier. If it is too small, you will find the tap makes the hole bigger without getting a grip in the metal and cutting a thread.

The correct size of hole depends on factors including thread form and thread size. There are a lot of thread forms, such as Whitworth, BSF and BA, for which drill size tables are available online. I include here tables for the smaller metric threads and Whitworth threads that are commonly used in older machinery.

Taps

Taps come in all sizes and threads. You can identify the right tap to match an existing male thread such as a bolt by placing them side by side with the thread peaks lined up. Hold them up to the light, and you can see any mismatch further along the tap. If the diameter matches too, you probably have the right one.

Each thread type and size has three corresponding taps, though you don’t need all three for through holes. They differ only at the point. The first cut tap has a long taper to help start the thread, the second cut has less taper and the bottoming tap has none, because it works when the other taps have already made the start.

As well as the taps, you need a tap wrench.

Cut the thread

When tapping a thread, it’s necessary to align the tap accurately with the hole so that they are coaxial. A crooked tap will not produce a good thread. In shallow holes it is less critical, but the deeper you go the more severe any misalignment becomes, and the tap will break. The first couple of threads set the alignment. Don’t try to pull the tap straight once the thread has gripped the tap, it’s too late then. You can sometimes correct it by drilling the hole bigger at its opening and re-starting the thread further in.

A good way to start the tap squarely is to grip it in the chuck of the bench drill used to make the hole. That keeps it on track, but you have to turn it by hand, using the drill lever to keep gentle pressure on the tap so it enters the hole and starts self-feeding. Once the first cut tap is securely held by the thread it has cut, you can switch to the tap wrench. Just wind the tap in as far as it will go, taking care not to bend it. Small taps break easily. Then, if it is a blind hole, change to the second cut, which will go further in, then to the bottoming tap, which will complete the thread to the bottom of the hole. Before bottoming, clear out the swarf.

Another method for aligning the tap is to drill a clearance hole in a bit of scrap metal or wood and clamp it above the hole for the tap. The tap will slide through the clearance hole, which will hold it square. The clearance hole must of course be drilled square.

Lubricate the tap

Lubricate the tap to give a better finish to the thread. There are special compounds, but oil will do. The swarf cut by the tap has to be broken up as you go. To do this, advance a little then turn backwards a bit, going two steps forward and one back. If you don’t, the tap can get locked.

Blunt taps are hard to turn and may seize. You can sharpen them with a narrow, round-edge grinding wheel, but it is easier to replace them. Watch for this if buying second-hand taps, they were probably disposed of because they are blunt.

Metric tapping drill sizes

Tap                        Metric drill               Imperial drill

3 mm × 0.5           2.5 mm –

4 mm × 0.7           3.3 mm –

5 mm × 0.8           4.2 mm –

6 mm × 1.0            5.0 mm –

7 mm × 1.0            6.0 mm                      15/64

8 mm × 1.25           6.8 mm                      17/64

8 mm × 1.0             7.0 mm –

10 mm × 1.5            8.5 mm –

10 mm × 1.25          8.8 mm                      11/32

10 mm × 1.0            9.0 mm –

12 mm × 1.75          10.3 mm –

12 mm × 1.5             10.5 mm                    27/64

14 mm × 2.0             12.0 mm –

14 mm × 1.5              12.5 mm                    1/2

16 mm × 2.0              14.0 mm                   35/64

16 mm × 1.5                14.5 mm –

Whitworth tapping drill sizes

Size (in)                  Tapping drill size

1/16                          Number Drill 56 (1.2 mm)

3/32                          Number Drill 49 (1.85 mm)

1/8                            Number Drill 39 (2.55 mm)

5/32                          Number Drill 30 (3.2 mm)

3/16                           Number Drill 26 (3.7 mm)

7/32                           Number Drill 16 (4.5 mm)

1/4                             Number Drill 9 (5.1 mm)

5/16                           Letter Drill F (6.5 mm)

3/8                             5/16 in (7.94 mm)

7/16                           Letter Drill U (9.3 mm)

1/2                             Letter Drill Z (10.5 mm)

9/16                           12.1 mm (0.4764 in)

5/8                             13.5 mm (0.5315 in)

 

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Turning metal on a wood lathe. Small items are possible

Aluminium finial turned on a wood lathe

Turning metal on a wood lathe is possible, even though the wood lathe is not designed for it. Lathes are designed specifically for either woodturning or engineering purposes, rarely both. Heavily-built engineering lathes work better than wood lathes. Their tool holder rigidly clamps the cutting tool and moves mechanically. But if you don’t have an engineering lathe and aren’t too ambitious, you can turn many small items in brass, aluminium or even steel freehand quite successfully on a wood lathe. The finial shown above was turned on my Graduate Shortbed lathe, mainly using a small gouge. It was threaded onto a bit of 12 mm studding held in a chuck, with tailstock support, and sanded to an acceptable finish. It is about 5 inches tall.

There are problems to overcome. Holding the tool so that it cuts steel is difficult. The hardness of the metal resists the cut, and the cut is very liable to ‘chatter’. This is vibration that leaves a rough or ridged surface on the work. Working freehand, accuracy is harder to achieve. Without a tool slide, accuracy comes from the turner’s skill. Making true cylinders or flat surfaces accurate to a thousandth of an inch freehand is not easy. But many items don’t need such precision.

Interrupted cuts, such as turning the corners off something, are particularly difficult freehand because it is hard to control the cutting tool. It is risky, too. Some wood lathes have a proper slide rest as an accessory.

Preventing chatter

Woodturners are familiar with the problem of chatter. When turning metal on a wood lathe it is hard to avoid. To prevent chatter, you need a strongly built lathe, with good bearings. It must hold the workpiece firmly, with minimum projection from the headstock. For example, modifying a drive centre while it is in the spindle taper is easy. A similar job held in a chuck is harder, because the metal can move away from the cutting tool.

Use tailstock support whenever possible. A Jacobs chuck will hold small items. Light cuts using a robust and sharp tool, with minimum projection over the toolrest, should then produce an acceptable result.

The tools

You can use a high speed steel woodturning scraper or a graver. A graver, which you can easily make yourself, was traditionally made from square section tool steel with a diagonal flat, leaving a long point at one corner. You could convert a triangular or square file, but a high speed steel tool bit would be better. A round high speed steel bar ground with a pyramid point would work. It would be similar to a woodturning point tool, but with a more obtuse point. Use a graver a bit like a skew chisel. Its edges (not the point) can plane off long, thin curly shavings from steel.

Brass likes tools with zero top rake, so responds well to scrapers. Tools leave a polished surface on brass. Aluminium turns with a graver or even a small short-beveled bowl gouge. Cutting speeds are lower than for wood, but because only small items are possible, the normal low-speed setting on the lathe is probably OK. Some metal alloys are more free-cutting and ‘turnable’ than others. A file will shape the item and remove chatter marks if necessary. Even on a lightweight lathe you can make simple shapes in steel using a file or a rotating grinding wheel held in a drill chuck.

Turning metal on a wood lathe is tiring, particularly with steel, because the tool must be held firmly up to the work. It helps to use a pivot pin in the toolrest to lever the tool into the work. This gives more control. If the workpiece is held rigidly, the pivot pin can help prevent chatter too. A heavy cut can increase it.

Safety when turning metal on a wood lathe

Turning metal freehand is hazardous, therefore precautions are necessary. It is essential that the workpiece is secure in the lathe. Chunks of metal flying out of the machine are even more likely to do you harm than are lumps of wood. Eye protection is a must. The swarf is sharp and hot – wood chips hitting your hand are annoying, but metal swarf can cut. Long strands could even catch your fingers and drag them in. Never clear away swarf while the lathe is running.

Turning with a scraper can make chips like little needles. They can get in your skin like splinters. But gloves are risky around moving machinery because they can catch and drag your hand in. Thin ‘rubber’ gloves that tear are safer. A bad dig-in could wrench the cutting tool badly enough to break it and perhaps cause injury. A file thrown back by the chuck jaws can injure you. They must always be used with a proper handle to stop the tang impaling your hand.

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A homemade centre finder is easy to make and quick to use

One kind of centre finder on the market has a slot for a pencil to mark intersecting diagonals. These work well on squared timber, but are a bit slow to use on a batch of items. Another kind has a blade. You position the blank, tap it so the blade makes a diagonal line, then repeat. I’ve found that this type can easily start splits in the wood, and needs the end of the blank cut square.
The centre finder I used for a long time is simply a small wooden block. The block has a hole drilled that is a push fit for a short pencil. The hole is off centre. By turning the block on different sides there is some height adjustment. To use it, I put the spindle blank and the pencil block on a flat surface and mark a line across the end of the blank. Then I flip the blank 90 degrees and repeat to do all four sides. The result is a small square marked on the end of the blank, from which I can easily find the centre by eye. This is not super-accurate, but good enough for most purposes, and it is quick. I have several blocks in different sizes so I can pick the one most suited to the size of the spindle blank. The blank need not be square and the pencil block can mark cylinders equally well. The point of a nail works too, and stays sharp.
pencil block centre finder
Pencil block centre finder
adjustable centre finder
Adjustable centre finder

I’ve now made an adjustable version of the pencil block, with a pivoting arm to hold the pencil. The hole for the pencil has a slot through it and a pinch bolt to lock it.

To find the centre of a bowl blank, I usually use a hardboard disc of appropriate size. I have a lot of these in different sizes for marking out bowl blanks, and each has a small hole in the middle. I just lay one on the blank, and place it quite accurately by eye or touch. Then I mark the centre with a pencil through the hole.
chuck insert centre finder
Chuck insert centre finder
When I need more accuracy, I use a chuck insert centre finder. This is a short dowel with a steel point in one end. I turned the insert to fit inside the body of my engineering chuck. I put the chuck on the bench and adjust the jaws to be a sliding fit on the spindle blanks. The blanks must be square or cylindrical. A tap on the end of the blank pushes it onto the point to mark the centre. This is a good method to use when part of the finished item needs to be left square.
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A ball cutting jig can be made from a machine slide.

Turning a sphere freehand will test your skill, particularly if you need two the same size. If you want more than one or two and don’t want to do them freehand, you can use a simple homemade or commercial ball cutting jig. I make lots of balls in a range of sizes, and for me a jig that lets me produce them quickly and accurately is essential.
The most basic ball cutting jig is simply a clamp to hold a cutting tool, with a pivot to allow the tool to swing through a quarter circle or more, all fixed to the lathe bed.  The cutting tool is sometimes adjusted in the clamp, or there could be a sliding adjustment so the clamp itself moves. But every commercial ball cutting jig I have seen is a bit flimsy or lacks easy adjustments. The cutter is usually advanced just by pushing it forward by hand. Sometimes there is no adjustable stop to control the finished ball size.
I made a heavy-duty ball cutting jig. It does a very good job cutting balls and can also make hemispherical hollows. It was easy to make, but would not have been so easy if it was not based on scrap parts. The key component is a machine slide such as top slide from a metal turning lathe. These can be obtained from dealers in old tools, or from Ebay. Mine has a rack and pinion lever feed. This is ideal because it is fast to use, but screw feed would be fine. I made the rest of the ball cutting jig from bits of scrap steel. The construction details depend on what lathe and machine slide you have so I can’t give more than guidance. Assembly would probably only involve drilling, tapping and bolting together.
homemade ball cutting jig
Jig set up on Graduate shortbed lathe
If you would like to make a ball cutting jig like this but have never done any work with mild steel before, don’t worry. Think of the steel as like very hard wood. You can cut it with a hacksaw, or if it is thick, drill a line of holes close together and saw through them. Drill the holes with a twist bit in a drill press because it is difficult to drill freehand, even with a power drill. You can cut screw threads in steel with a tap by screwing it into the correct size hole.
The ball cutting jig (see cross-section plan below) consists of the following components, starting at the bottom and working up:
  • A clamping plate that will hold the jig to the lathe bed, allowing it to slide and lock
  • A locating block (not shown on plan) that fits the lathe bed so the jig can slide along parallel to the bed without sideways movement. This makes locating the pivot point with reference to the ball centre much easier as you can just slide the jig along to the right place. You have to make sure the centre of rotation of the jig passes directly and accurately under the turning axis of the lathe. The short bed on my Graduate lathe has a slot that is offset a little, so I offset the jig to match. The locating block is not load bearing, it just positions the jig before locking down, so wood would do.
  • Next is a pivot plate sitting on the lathe bed. Make it thin, but rigid. The thinner it is, the more clearance space you have and the larger the ball you can make. A steel disc about 10 mm thick and 100 mm across would be ideal. Mine is much thicker, because that is the scrap that I had at the time.
  • A rigid slide support platform sits on the pivot block. The mating surfaces of the pivot block and the slide support platform are the pivoting plane. The ideal for the support platform would be a strip of steel of width to suit the slide, and 12 mm thick. If the strip is too short it limits the ball size unnecessarily. I rounded the end of the support platform to clear the headstock.
  • The clamping plate, guide block, pivot plate and slide platform are all locked together with the pivot pin. This could be a 12 mm or larger steel rod, threaded where necessary. Firmly anchor it in the pivot block. You could screw it into a tapped hole in the pivot block and secure it with thread lock compound. This provides two separate clamping actions – one from below to lock the jig to the lathe bed and another from above to adjust the swivel tension.
  • The pin passes down through clearance holes in the guide block and clamping block. This allows a nut and washer to pull the pivot plate down on the lathe bed, positioned by the guide block and held by the clamping block. Above the pivot block, the pin passes through a snug-fitting clearance hole in the slide platform.
  • Above that are a washer and two nuts that lock against each other to set the pivot tension. The pin should preferably be unthreaded where it passes through the slide platform. This is a bearing surface for the pivoting movement. But even a screw thread should give adequate guidance, assuming the hole is a snug fit. The top of the pin needs to have its centre marked to set it exactly beneath the centre of the ball when in use. I turned a point on mine. If the ball turning jig is not lined up properly, the ball it makes will not be perfectly round.
  • Bolt the machine slide to the slide support.
  • The moving slide carries the tool holder. The tool holder on mine came from another old machine, but you could make a similar one by bolting three bits of steel together. It stands on a raising block to bring the tool to the lathe centre height. Having it a little low allows you to use different cutters, with shims. If the cutter is not on centre height, the ball will not be spherical.
  • You need an adjustable stop for the slide movement. How you do this will depend entirely on what slide and other parts you have. I used a bit of threaded rod with two adjustable lock nuts, passing through a clearance hole in a bit of metal attached to the slide. The cut stops when the metal contacts the adjusting nuts. By counting movement of the nut flats, I can adjust the cutting depth and size of the ball very accurately.
limiter for homemade ball cutting jig
Lock nuts limit the slide travel
The largest size of ball you can make depends on the clearance above the top of the swivel point and the travel of the slide. If you make a ball from a cylindrical blank, the clearance needed is more than the radius of the ball. Even more so if you use a square blank, And you have to allow for projection of the cutter.
tool holder for homemade ball cutting jig
Tool holder
 To use the ball turning jig, position the swivel axis directly beneath what will be the centre of the ball. I normally make hemispheres with the blank held on a screw chuck, so position the swivel pin beneath the face of the chuck. I glue the hemispheres together to make perfect spheres. Advance the cutting bit, an ordinary round-nosed scraper. Pull the slide round to make a cut, then advance the tool for the next cut. When set up, I can very quickly make lots of identical half balls.
hemisphere cut with homemade ball cutting jig
MDF hemisphere cut with homemade ball cutting jig
A ball cutting jig of this kind cannot make a whole ball in one pass. You must hold the blank in the lathe, so the cutter cannot reach all the surface. It could make most of the ball for finishing off by hand. Or you could move the ball in a chuck so the cutter reaches the uncut parts. If you hold the blank in a chuck the cutter could do 75% or more of the circumference in one pass. It would leave just a single chucking spigot. If you hold the blank between centres, it leaves two smaller spigots.
A traditional way of hand turning spheres is to put the roughed out ball between two female cone centres. The spigots project sideways for turning off. Using this same method, you could finish the ball with the jig. It should leave a perfect ball if set up correctly.
 Cross-section of ball cutting jig
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Homemade long tool rest

A homemade long tool rest can be a useful accessory. It’s a great help if the tool rest is longer than the spindle you are turning by at least 25 mm at each end. This extra length gives tool access to the ends of the spindle, and it’s much easier to turn sweeping curves accurately if you don’t have to keep moving a short tool rest. Lathes don’t usually come with a very long tool rest as standard. One can often be bought as an accessory, at substantial cost. Over a certain length, a long rest needs two stems to keep it rigid and stop chatter.

It’s quite easy to put together a homemade long tool rest and a second holder to support it using hardwood. A wooden tool rest is pleasant to use, and was standard in past times. You will need to remove the sharp side edges on skew chisels to protect the wood. But that’s necessary for steel rests too. If the rest gets a lot of use, you may have to plane or sand the top smooth from time to time.

The stems

Make the two stems of round steel bar. One needs to fit your existing tool rest holder. The other can be any size because you will drill the holder to fit. The length should bring the top of the rest to the proper height when it is fitted into the wooden holder.

I made mine by drilling a hole in one end of each bar, using a tapping drill that matched a bit of threaded rod. I tapped the thread and screwed in a short bit of the rod. It was tight in the hole so it would stay secure. Inserting the rod about 25 mm deep and projecting about the same distance seemed about right. If you don’t have a tap, you could drill a larger hole and use adhesive to keep the threaded rod in place.

More simply, the steel rod could just be glued into a hole in the wooden rest.

The rest

My homemade long tool rest began life as an oak table leg, about 600 mm long, 40 mm thick and 50 mm deep. I find it quite strong enough. I planed the front to make a slope. Drill two tapping size blind holes in the wood for the threaded rod, about a quarter of the way along from each end. Screw in the stems.

You could tap the holes, but most hardwoods will not make a good thread using an engineer’s tap. If you cut the end of the threaded rod cleanly, the rod should make its own thread in the wood. This is the method I used. You could drill the holes larger and use epoxy instead, or glue the stems into the wood without using threaded rod at all. The main thing is to make sure the stems are parallel to each other and securely held in the wood.

The holder (banjo)

Use hardwood, say 60 mm thick, and drill a blind hole, say 45 mm deep, at one end for the second stem. Wood will probably not be strong enough to take a locking screw that will hold the stem firmly, so that limits height adjustment. You can raise the rest a little by putting a spacer in the hole under the stem.

Saw a slot in the holder that will fit over a clamping screw to hold it on the lathe bed.

A steel version of this holder could have a locking screw to allow easier height adjustment.

The clamp

Now make a clamping block that will fit your lathe bed. Its design will vary because all lathes are different. Mine is made of thick MDF and fits between the ways. It has a projecting lip underneath. A bolt passes through the block and is long enough to reach up through the wooden holder. A washer and nut clamps the holder in place on the bed.

homemade long tool rest
Homemade long tool rest

Plan of homemade long tool rest

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Harden steel using these simple methods

It’s sometimes useful to know how to harden steel. Although it’s possible to do woodturning with very few tools, I can never resist trying something new. Sometimes I buy tools, but often I make them myself. Back in the days before commercial tools were available, turners knew how to harden steel and temper it. They made their own tools out of high carbon steel, or got them from the local blacksmith. The best way to harden steel and temper it is to do it properly by modern methods. This requires the right steel for the job, with careful control of temperatures and timing and the rates of heating and cooling. But acceptable results can usually be obtained using the cruder methods described here.

Tool steel

Turning tools are now rarely manufactured from carbon steel, but it is still used for many other purposes. Even for turning tools, it still works as well as it did when the old-time turners made their living with it. You can buy high carbon steel in various grades from steel stockholders, some suitable for hardening in water and others in oil.

Scrap carbon steel is easy to find. If you want to harden steel for tool making, springs, files, saw blades, masonry nails, crow bars, cold chisels, woodworking chisels, old screwdrivers, plane irons and many other things are steel that is suitable for reworking. I have used the tines of an old garden fork and the rings from old ball races. Keep in mind that if you put the tool under significant stress, steel that has or may develop cracks is unsuitable. For example, the valleys between the teeth of a file are weak points where cracks can start.

If you are using scrap, old steel is often the best choice because some modern steel alloys may not respond well to these basic heat treatment procedures. One way to tell what you’ve got is to touch the steel on a grinder. Lots of bright bursting sparks like a child’s ‘sparkler’ firework mean it is probably high carbon steel. Try a bit of mild steel such as an ordinary nail for comparison. It will also make a lot of sparks, but there will be fewer bursters. The use of the metal before it became scrap is a clue – if it was subject to a lot of stress, the metal is probably high carbon steel. But there is a continuum of carbon content – to be sure, test-harden a piece before making the tool.

Low carbon mild steel

Ordinary low-carbon mild steel is not suitable for most cutting tools. You cannot harden steel of that kind, and it will not keep a sharp edge. To harden steel, the metal must have a high enough carbon content. The metal is harder than wood, and a cutting edge on mild steel may last long enough for a one-off job. But if the edge is thin it will just give way under pressure. You can case-harden mild steel. This gives it a very thin layer of higher carbon content on its surface. Then you can use it for some light-duty cutting tools provided you don’t grind away the hardened skin when sharpening. To case-harden, coat the metal with a special compound before heating. You can use mild steel as a holder for inserted or brazed-on cutters.

Equipment needed

To harden steel, you must first make it hot. You can use a magnet to check that it is hot enough for hardening – when the magnet stops attracting it, the steel is ready. More simply, just get it red hot, which is also the temperature needed for hot forging. The bigger the piece, the more heat you will need. If the item is small, you can harden steel using a burner on a gas cooker. You can use a charcoal fire with a blower to supply air.  You can do a lot with a reasonably powerful blowtorch. Larger pieces of steel may dissipate the heat as fast as it is applied, never getting hot enough. If using a blowtorch, you can stack a few dry bricks to make an enclosure to retain the heat.

A simple forge burning solid fuel or propane is not hard to improviseThere is video on YouTube about making a simple but very effective propane forgeI made a forge that burned anthracite and worked 7/8 inch bar without too much trouble. More recently I made a propane forge using just two insulating fire bricks and a blowtorch, and was able to bend steel strip of about 2 inches width and 3/8 inches thick.

Hot forging

If you make two pieces of steel white hot, you can weld them together by hammering. Hotter still, the metal will burn and spoil. But these temperatures are harder to reach with the sort of equipment described.

If you want to do any hot forging, you will need something to use as an anvil, a hammer, vise and heavy pliers. You may also need a hacksaw, angle grinder, file, bench grinder and a drill press. To work thick steel, you will need heavier tools and a forge.  If it’s hot enough, it’s surprisingly easy to bend steel using a vise or wrenches, or to hammer it into shape on an anvil. You can forge ordinary mild steel in the same way.

Annealing

Some scrap carbon steel is too hard for sawing or filing into shape. You will have to anneal it to make it softer and workable. To do this, the first step is to make the metal red hot. While it is hot, you can forge it. Don’t try to work the metal when it has lost its red heat or it may crack. You have to strike while the iron is hot. After any forging, get the steel red hot again and then anneal it by cooling it slowly. The slower it cools, the better – traditionally the metal was left to cool buried in hot ashes. If using a propane forge, you can just leave the metal to cool in the forge so the residual heat will slow the cooling. You want the whole piece uniformly softened, so try to heat and cool it evenly.

When cooled, the annealed steel should be soft enough to file. Check that all parts are soft, then carry out whatever further operations you need. Shape the tool, including rough grinding the edge.

Harden the steel

To harden steel, heat the part to be hardened bright red hot again, if possible ‘soak’ it in the heat for a bit, then quench it. It’s the rapid change from red hot to cold that will harden steel. You can use various quenching liquids, but a bucket of water will usually do the trick. Plunge the red hot metal straight in, and swirl it about to cool it as rapidly as possible. If the steel warps or cracks when quenched, try using oil instead of water, or use different steel. If using oil, fire precautions are necessary. Use a metal container, not a plastic bucket. The hot steel will heat and ignite the oil, so have a metal cover handy to extinguish the flames.

You don’t always have to harden all parts of a tool to the same degree. If it must withstand stress in use, you can leave the bulk of it soft, for toughness and strength, with just the cutting tip hardened.

After quenching, the steel should be glass-hard and a file will just slide off it without cutting. Don’t try too hard with the file, the hard metal will soon make it blunt.

Tempering

The freshly hardened tool will be brittle. If you were to use it in this state, the edge could chip or it could shatter. For most purposes, you must heat it one more time to temper it before use. Tempering takes away the brittleness. It makes the metal tougher, but softer. The higher the temperature reached during tempering, the softer and less brittle the steel will become. Each tool has its own optimum compromise between hardness and toughness.

Before tempering, clean up the metal using abrasives. You want the steel bright and shiny for this stage. Warm the tool very carefully above, not in, a clean flame. Watch the bright metal surface carefully as it heats up. Let the heat start away from the edge and creep towards it, aiming for a uniform temperature over the surface. The edge and any other thin parts will heat up too fast if exposed to the heat directly.

Watch the colour change

As it gets hotter, you will see the bright steel change colour. It will go from silvery to a pale yellow, through brown to blue and then to grey. You have to catch the moment when the colour you want reaches the edge. Normally a pale yellow-brown colour at the edge of a cutting tool is about right for cutting wood, but different tools may need other colours. A blue colour will leave the steel tough and strong, but not hard enough to keep a cutting edge. (Springs are tempered to blue, and some steel components such as screws are blued for decorative purposes.)

Don’t let it get too hot

If you let the metal get too hot you will have to repeat the hardening stage. You can repeat the annealing, hardening and tempering without harm to the metal. But too long at high temperature can tend to burn out the carbon from the surface layers. When the colour is right, quench the tool again. It is then ready for final clean up and sharpening before being put to use.

Sometimes you need more accurate tempering, for example if you need a larger piece evenly tempered. You can do this by heating the item in an oven at a set temperature, or in oil. You will need a thermometer for these methods. They allow for soaking at the proper temperature, which may give better results.

 

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Bowl reversing jaws are easy to make using carrier plates

bowl reversing chuck

Bowl reversing jaws are useful to hold some kinds of bowls by their rims while you finish turning their foot. You can buy sets ready for use, but I recently made my own. I screwed plywood quadrants to steel carrier plates like these that match my chuck. I fixed movable pegs to the quadrants. The pegs form a circle that grips the rim of the bowl. I did the final turning of some of the bowls I sell here using this homemade kit.

First attempt at bowl reversing jaws

The first pegs I tried were pre-drilled rubber bungs from a home-brewing supplier. They have a taper, which gives them a dovetail grip. I drilled holes in concentric circles on the quadrants and fitted 8 mm tee nuts (the kind with prongs to hammer or press into the wood). 8 mm bolts held the bungs firmly in place. There was a neat ring of 8 bungs on the bowl reversing jaws ready to grip almost any size of bowl.

I expected the soft rubber to give a non-marking grip and accommodate small positioning errors. But the rubber bungs were a bad idea because they had too much give. So any but the lightest cuts would move the bowl in the jaws. Therefore I turned a set of wooden pegs to replace the bungs. Another option would be to make wooden jaws, fixed to the plates and turned to give a more even grip on the bowl.

Making wooden pegs

This was an easy job. I cut a number of short sections of a moderately soft timber and drilled an 8 mm hole right through the middle of each one. I mounted them in the lathe between a conical ‘dead’ centre in the headstock and a live centre in the tailstock. The dead centre had enough friction to drive the piece. Doing it this way ensured that the holes were central in the finished pegs.

I turned the pegs all to the same size as the rubber bungs. They are 30 mm long, 30 mm wide at the top and 26 mm wide at the bottom. I could have used shorter pegs, but I had the bolts the right length for that size. I used a parting tool and calipers to set the greatest and least diameters. A sharp spindle roughing gouge cut the slight taper. I used a skew chisel to square the ends so they would sit firmly on the quadrants.

Testing the new pegs

I used them to remove a temporary chucking tenon from the base of a Robinia bowl. They held better than the rubber bungs. But bowl reversing jaws of this type never give the most reliable grip and heavy cuts cannot be taken. Tailstock support will give more security. I can foresee that wooden pegs could mark or damage a fragile rim, so care will still be needed for that reason too. I have heard of people using a rubber sleeve over a wooden core. Rubber tubing or even plastic hose pipe might work for this.

Bowl reversing jaws
Wooden pegs to grip bowl
bowl reversing chuck
Tee nuts in back of chuck
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Homemade hook wrench

homemade hook wrench

A hook wrench is very useful when a chuck or faceplate gets stuck on the lathe spindle nose. They have to be secure, particularly if you run the lathe in reverse, so can get too tight to remove easily.

Lathe manufacturers don’t always cater for this very well. They may provide a tommy bar, but these are often unsatisfactory. Unless the bar is stout it will bend, and if the hole for it is shallow the metal around it will distort. Soon, the bar becomes too loose.

A hook wrench causes much less distortion. They may not be easy to find in the right size, but adjustable ones are available.

It’s easy to make a hook wrench from steel rod. The first step is to make a short peg at one end that will hook into the tommy bar hole. I hot forged mine by making the end of the rod red hot with a blow torch, then hammering it into an L shape. I used the square edge of the vise jaws to make the bend a tight right angle. Using a file, I shaped the short arm to fit the tommy bar hole and trimmed it to about 1/4″ long. The arm needs to be at a right angle to prevent it slipping. Another method would be to drill a cross hole in the rod and rivet in a short bit of smaller rod. Or you could weld a bit onto the end of the rod.

homemade hook wrench
Hook wrench to fit screw chuck

Then the rod has to be bent to wrap round the chuck. It should go round at least a quarter of the circumference. The rest of the rod forms the handle. This is best done with the metal red hot. You need a large burner or a small homemade forge. But the rod could be bent cold if you have a heavy vice and it isn’t too thick. Make the bend to match the curve of the item if possible. It is better to have it too tight than too loose. High carbon steel can be hardened and tempered. I used a bit of scrap mild steel rod about 3/8″ thick, unhardened. It seems to be quite strong enough for light duty.

This hook wrench easily loosens my screw chuck – just a tap on the handle does the job.