I've spent a lot of time hunched over a workbench, but nothing quite beats the workflow of a covington flat lap when you're trying to get that perfect mirror polish on a slab. If you've been into lapidary work for more than a few months, you probably know the name Covington. They've been building these machines forever, and there's a reason you see so many of those old, green-painted units still kicking around in garages and professional shops. They're built like tanks, and honestly, they just work.
When I first started out, I was mostly using vertical wheels. Those are great for cabochons, sure, but the second you want to flatten out a piece of petrified wood or get a glass-smooth face on a thunder-egg, a vertical wheel starts to feel like the wrong tool for the job. That's where the flat lap comes in. It gives you that wide, horizontal surface area that makes it so much easier to keep things level.
Why the Heavy-Duty Build Matters
One of the first things you notice when you unbox a covington flat lap is the weight. This isn't one of those lightweight plastic things that's going to vibrate its way off your workbench the second you turn it on. Most of their units are made with heavy-duty cast iron or thick aluminum bases. That weight is your best friend. It absorbs the vibration from the motor, which means your hands don't feel like they're buzzing for three hours after you finish a session.
Let's be real—lapidary work can be messy and loud. But because these machines are so well-balanced, they run surprisingly quiet. You can actually listen to a podcast or have a conversation while you're working, which is a massive plus in my book. The motor is usually tucked away or shielded well enough that you don't have to worry about water getting into the guts of the machine, which is obviously a pretty big deal when you're constantly dripping coolant.
Getting the Water Flow Just Right
The water system on these machines is pretty straightforward, which I appreciate. Usually, it's an overhead drip system. It's not fancy, but it gets the job done. You want just enough water to keep the disc wet and the rock cool, but not so much that you're creating a literal fountain in your workspace.
I've found that the covington flat lap handles the "splash factor" better than some of the cheaper alternatives. They usually come with a decent splash guard or a high-rimmed pan. You're still going to get a little bit of spray—that's just the nature of spinning a wet disc at high speeds—but it stays mostly contained. A little tip if you're working in a small space: I usually wear an apron anyway, because no matter how good the guard is, you're eventually going to get a mystery streak of rock slurry down your shirt.
The Versatility of Disc Sizes
Covington offers these in a few different sizes, usually ranging from 6 inches up to 12 inches or even larger for the industrial-grade stuff. If you're just starting out, an 8-inch or 10-inch model is usually the sweet spot. The 6-inch is fine for small gems, but it feels a bit cramped if you're trying to polish anything bigger than a silver dollar.
The 12-inch covington flat lap is a beast. If you have the space and the budget for it, it's a total game-changer. Having that extra surface area means you don't have to move the stone around nearly as much to cover the whole face. Plus, it gives you more "real estate" to work with if you're trying to get a perfectly flat grind on a larger specimen.
Grits, Discs, and the Grinding Process
The magic really happens in how you swap out your discs. Most people use a master lap (a solid metal or plastic plate) and then stick different diamond discs or polishing pads on top of it. Some folks prefer the magnetic backing systems because it makes switching from a 220 grit to a 600 grit take about five seconds.
When I'm working on a piece, I usually start with a fairly aggressive diamond disc—maybe a 100 or 180 grit—to get the saw marks out. The covington flat lap provides enough torque that you can really lean into it if you need to, though you should usually let the diamonds do the work. Once those scratches are gone, you just work your way up through the grits. By the time you hit 1200 or 3000, you start to see that "wet look" even when the stone is dry.
One thing I really love about using a flat lap for the final polish is using a felt or leather pad with some cerium oxide. Because the surface is flat and stable, you can get a mirror finish that's almost impossible to achieve on a rounded wheel. It's incredibly satisfying to see a dull piece of rock turn into something you can practically see your reflection in.
Maintenance and Keeping It Running
If you take care of a covington flat lap, it'll probably outlive you. But you can't just ignore it. The main thing is keeping it clean. Rock slurry is basically liquid sandpaper, and if you let it sit and dry in the pan, it turns into something resembling concrete. I always make it a habit to rinse out the pan and wipe down the spindle after every use.
Checking the belt tension every now and then is a good idea too. If the machine starts to make a squealing sound or feels like it's losing power, the belt probably just needs a quick adjustment. It's a simple mechanical system, which is one of the things I love most about it. You don't need a degree in electrical engineering to fix most common issues; usually, a wrench and some common sense are all you need.
Is It Worth the Investment?
I won't sugarcoat it—Covington equipment isn't the cheapest on the market. You can definitely find plastic flat laps online for half the price. But here's the thing: those cheaper machines often have weak motors that bog down when you apply pressure, or the shafts aren't perfectly true, leading to "wobble." A wobbling lap is the fastest way to ruin a good piece of stone.
With a covington flat lap, you're paying for precision and longevity. It's the kind of tool that stays in the family. I know people who are still using Covington laps they bought in the 70s. When you factor in how many cheap machines you might go through in forty years, the "expensive" option actually ends up being the cheaper one in the long run.
Final Thoughts for the Shop
At the end of the day, your choice of equipment depends on what you want to make. If you're only doing small, rounded cabs, you might not need a flat lap. But if you're like me and you find yourself constantly picking up interesting slabs or wanting to create geometric shapes and flat facets, the covington flat lap is pretty much the gold standard.
It's a straightforward, dependable machine that doesn't try to be anything it isn't. It spins a disc flat and true, stays where you put it, and handles the grind day after day. Whether you're a hobbyist working out of your garage or someone looking to sell your work at gem shows, having a reliable flat lap in your arsenal just makes the whole process a lot more enjoyable. And honestly, isn't that why we do this in the first place? To spend less time fighting with our tools and more time seeing what's hidden inside the rock.