Inexperienced turners find copy turning quite intimidating. But making two or more pieces the same need not be difficult. After all, when you have turned the first you have proved your ability.
Copy turning attachment
A copy turning attachment for your lathe is one option. But it’s only really worthwhile if you have a great many items to do. The attachment must be paid for, set up and taken down, and may get in the way when not in use. It may not even save time. For most turners it’s probably better to save money and benefit from the practice that hand turning will give you. Soon you will be able to make duplicates so quickly that you will surprise yourself. Making lots of the same item is an excellent way of building your skills. You will find you can then make other shapes much more confidently and fluently. And why take up woodturning if you don’t want to do the turning?
When you make a set of turnings, they need to be very similar, both to each other and to the original pattern. But it’s rarely necessary for copied items to be indistinguishable. Slight variation is almost always acceptable, even desirable. It shows that the items are handmade. If you look at antique furniture you may well see minor variation in the spindles. It’s part of the charm of the piece. Of course, this is not an excuse for sloppiness. Generally, the closer together you place two items, the more closely they should resemble each other. At the other extreme, if the items are to be sold separately, a family resemblance may be enough.
The most important dimensions of a spindle being copied are usually the overall length, the maximum and minimum diameters, the diameter of any tenon or fitting, and the position of beads or other prominent features. The exact size or shape of beads, fillets and coves is not normally so critical. If one finished item does not stand out markedly from the others, the set is probably OK. But the tighter the specification, the more care has to be taken with measurements, marking out and the turning.
Tips for copy turning
It’s probably not worth attempting copy turning (unless you are doing it just for the practice) until you are able to produce beads and coves with reasonable reliability. Assuming you can do this, first make one complete item to your satisfaction. This proves that you can do the job, and is a sample that acts as a guide for the rest. Make a holder for it that positions it just behind the lathe so you can see it when working on the others.
When doing the rest of the items, it helps if you break the task down into steps and put all the items through each stage before going on to the next. The advantages of this are first that the practice gained from carrying out that step on the first item is immediately put to use on the next. Secondly, you can see as you go that each one is within tolerance. You should start with some spares to allow for any rejects along the way.
This is not the most efficient method of production, as you must spend time changing over the blanks. So with more experience you will probably complete each item before going on to the next. However, by working in small steps the turning is simpler, mistakes may be less likely, and you will soon become quick and confident at each stage.
You may have a motley collection of scrap wood to work with. If so, it makes the copying easier if you start by making the blanks identical. You will then have a stack of cylinders all the same size. Make them just slightly more than the maximum diameter of the finished piece to allow for sanding.
Make a template by marking the key points from your sample onto a piece of thin ply. You can offer this up to the spinning blanks and mark circles on them with a pencil. The number of points and circles will depend on how accurate you want the copies to be. Usually, I mark the centre line of each bead, the position of any tenon and the overall length of the item. I don’t normally mark or measure the width of beads or hollows or fillets. This is partly because if there are too many lines drawn on the blank it is confusing and leads to errors.
If this is a job you will repeat in future, label the template, sketch the item on it with the marks for the key points in the right places, write the relevant finished diameters and size of the blank and put it somewhere safe.
Prepare the tools
Sharpen and lay out the tools for the job. If possible, have enough pairs of calipers to make all measurements that you need – not usually more than three or four. Set them to slightly over the relevant finished diameters to allow for small errors and sanding. In softer wood the calipers can damage the surface, so if possible don’t use them right on the crown of a bead. Calipers without lock nuts can open slowly in use, which is a common source of error. Lay them out in order so you don’t mix them up. You might label the calipers to correspond to the positions on the marking strip. With practice, you may find that you only need to use one or two pairs. You can judge other diameters by eye, using the measured diameters or sometimes the drive centre or tail centre as points of reference.
Use a parting tool to set the bead diameters with the calipers. When you have set the diameters, if the shape permits it, part in on each side to block out the beads, centred on the marked lines. With practice you will have the confidence to set the width and depth by eye.The parting cuts both locate the beads and make clearance for the gouge or skew. Sometimes there is no room for the parting cut, for example if there are two beads side by side. Then you will have to make V cuts instead with the skew or spindle gouge.
Turn the shape
When copy turning, turn the beads first, then the coves, then clean up the fillets. Measure if you need to, or if the size is critical, but try to set the width of any fillets and the depth of coves by eye. Aim to get all fillets on an item of equal width, and all coves and beads properly shaped. If you shape them properly, the finished dimensions should come out right each time. Pay particular attention to the shape of larger coves and beads and sweeping curves. Size the tenons, if any. Like many turners, I use a spanner to get the diameter right, cutting with a parting tool.
When you have finished the batch, line them up and pick out any rejects. If you need small sets, sort them into groups that match best. Here are a few spindles I made using these methods. They are part of a batch of 200. After sawing the blanks to size and turning the first three, the only measurements necessary were to mark the positions of the beads and to size the tenons. Because these spindles are small, I used multiples and fractions of the tool width to position the beads.