Mr Johan de Vries
Shared tolerances
±1 mm habits that keep partner kilns and our jigs honest.
In the Woodstock atelier, we live by the tape measure and square, but even more by the patience to respect the ±1 mm that makes or breaks a batch. Sharing our Ceramic Studio Jig with partner kilns has taught us as much about precision as it has about trust.
Read it alongside the Ceramic Studio Jig page.
Defining ±1 mm in the everyday workshop
When we build jigs for ceramics, our ±1 mm tolerance is not just theory, it’s a habit. Our typical guide is cut from well-seasoned hardwood, which holds its shape despite the shifting Cape humidity. Each guide is filed to spec, and we check with a gauge block before handing it over. That last millimetre can mean the difference between a plate that nests perfectly or rocks on the table. We check every edge by eye and hand, no quick passes. Even a tiny nick on the file can catch clay, so we sand and oil the wood lightly to keep the action smooth.
Working with small batches, sometimes just a dozen blanks, means you spot even the smallest drift in a set. We’ve learnt to leave our batch to rest in the same room as the ceramics team, because a cold morning in Woodstock makes the wood contract just enough that a new batch cut later can come out tighter than the first one.
Open jigs and digital files: sharing means checking twice
We share the DXF files for our Ceramic Studio Jig with studios from the Karoo to Joburg, but digital files don’t always mean the cut comes out right. Workshop bakkies drive different routes, and the plywood or hardwood you buy in Durban isn’t quite the same density as ours here in Cape Town. After a studio runs their first batch from our file, we ask them to send back a photo with a tape measure for each key dimension: length, width, guide slot and pinhole. When we spot a problem, it’s often a cheap cutting bit or an old CNC with a worn bearing that wobbles out a few extra tenths.
If the kiln shifts during a Highveld thunderstorm or a rainy Cape southeaster pushes moisture into the workshop, we know to wait and check again. It’s tempting to push through, but kilns can stretch a plate by another millimetre on a humid day. ±1 mm is a shared promise, so we keep a record of the measurements for every batch and update our partners if we tweak the file.
Mistakes we’ve seen and how we keep ourselves honest
We’ve learnt the hard way to spot the little errors that creep in when you’re making forms for someone else’s fire. Once, a batch of guides warped in the Woodstock cold and nearly jammed a hundred plates in a Lowveld kiln. Another time, a hasty oiling left fingerprints that burnt onto the vessels in the firing, which only showed up weeks later. These are honest mistakes, but they cost time and trust.
Now, before every handover, we do a dry fit with fresh blanks and pass the guide to at least two pairs of hands for a sanity check. We keep a set of known-good hardwood samples labelled by season and location, so if a batch is going to Durban, we use the closest match. Even our oiling process has a checklist. Light oil, rub with a clean cloth, hang in the air for a day to cure. Nothing rushed.
- Check guide fit at room temperature and after resting overnight.
- Photograph and measure finished blanks before shipping.
- Label samples by season and region for repeatability.
- Dry fit every new batch with clay before sending to partners.
- Keep a written log of tool maintenance and oiling dates.
South African conditions: humidity, dust, and honest habits
Cape Town’s rain, Joburg’s dust, Durban’s humidity, all of them challenge our ±1 mm targets. We oil the hardwood guides because in KZN, an unoiled guide can swell by a millimetre overnight. Up in the Highveld, we run a humidifier in winter to keep the wood from shrinking too much. When we travel with the jigs to a partner studio, we wrap them in thick brown paper so they don’t pick up bumps or moisture on the road.
We’ve learnt to talk honestly with our partners. If their kiln has a bad day, or the jig didn’t land square, a quick email to atelier@creationafrica.co.za sorts it out. In the end, it’s these shared tolerances and habits, not the perfect dimension, that keep our jigs and the partnership honest.
Where to go next
See the Ceramic Studio Jig specs, then the install notes. For a full room brief, the Maker residency or Brand collab studio pages walk through a visit week. Finish samples live under finishes, and you can book a sample hour at a showroom.