Take your time
Take your time when doing production throwing. Set aside at least three hours. If you're short on time or feeling rushed, it's better not to start at all. Choose a quieter moment when you can work without interruptions.
Accurately weighing every ball of clay is an essential foundation. Record the weight for each form in a notebook. While you're at it, note down all the dimensions as well and add a sketch or a photograph. You'll be glad to have that information later.
Quantity matters
If you need four matching mugs, don’t wedge four balls of clay, prepare at least eight. You’re bound to lose a few along the way during throwing, trimming, or glaze firing. If you're relatively new to pottery, it's wise to prepare even more. Having to stop in the middle of a production throwing session to wedge extra clay will break your concentration.
By making enough extra pieces, you can select the forms that match best. Fire a few extras as spares and recycle the rest back into your clay.
Measurement is knowledge
Measure frequently while throwing and write down your measurements. Use a throwing gauge, preferably one with an adjustable pointer, such as those made by Julius Handmade. For taller forms, you can make a simple caliper from two sticks or wooden slats to estimate both height and diameter. A straight ruler works well for shallow plates.
Measure not only the finished form but also intermediate stages, such as the centred mound of clay. This makes it easier to reproduce each step of the production throwing process.
Commit!
Commit to a single form and throw it repeatedly. This is the only way to develop real muscle memory for that shape. Keep making the same form for a while, preferably across multiple throwing sessions. Avoid switching to a different form during the same throwing session.
Keep the rim even
Pay a little attention to the rim of the pot. Keeping it consistent throughout the series will make your pieces look more alike. Pay attention to both the thickness and the shape of the rim, whether it is rounded, flat, or something else.
Gain speed
If you really want to become good at production throwing, avoid unnecessary movements and work efficiently. Production throwing works best when you focus only on the essential actions. Repeat those actions consistently without adding extra, unnecessary steps. Keep everything as simple as possible. That way, you'll throw faster and more efficiently.
From small to large
Before you start trimming, take a close look at the shape and height of all your pots. Arrange them in a row from smallest to largest. Measure the height of the smallest and the tallest pot and compare the difference in height between them.
Start with the smallest piece and use it as your reference. Quickly compare the height of the next pot by placing it next to the finished one. This allows you to estimate how much clay needs to be trimmed from the base to achieve the same height.
Correct small height differences during trimming
There is little you can do to adjust the diameter of a pot at the trimming stage. The height, however, can still be altered. Remove slightly more or less clay from the base to compensate for small differences in height. For larger adjustments, you can trim some clay from the rim. Make sure the pot is firmly secured before doing so, and preferably shorten the rim before finishing the foot.
Equal feet, edges and curves
Your series will look much more consistent if the feet and foot rings are all the same width. Careful measuring before you start, combined with marking a small groove in the clay, can help tremendously. Try to keep the thickness of the foot or foot ring as consistent as possible as well.
Pay attention to the glaze line as well. You’ll need it to glaze your work easily and it also creates a subtle shadow beneath the pot. Make sure it is consistent in width, depth, angle, and shape throughout the series.
You can also make small adjustments to curves during trimming to create a more consistent set of forms. There’s only so much you can do, as the inside shape largely determines the outside shape, but a little fine-tuning is always possible.
Practice makes perfect.
Pottery is all about practice, and the more you practise, the better you become. By repeating the same form over and over again, you build muscle memory. Your hands begin to make the movements automatically, without you having to think about them. The key is to keep going.
Together with De Cursist, I created a fantastic video workshop on production throwing.