A fettling knife is a narrow, pointed clay knife with a long blade that bends a little. Potters use it to cut slabs to size, trim the waste from a pour hole on slip-cast ware, shave off mold seams, and carve or sculpt leather-hard clay. For most home potters a classic Kemper F96 soft fettling knife covers all of that for under $10. Below we compare seven knives from maker spec pages and US dealer listings. This is a research-based comparison: we did not cut clay with these knives ourselves.
Not sure where a knife fits among the rest of your kit? Our pottery tools guide explains each basic tool by name, and our best pottery tools roundup covers full starter kits.
Quick picks
- Best overall: Kemper F96 Soft Fettling Knife (flexible blade, classic studio knife, low price)
- Best rigid fettling knife: Kemper F97 Hard Fettling Knife (stiffer blade for firm clay and clean straight cuts)
- Best stainless, double edge: Xiem XST-40 Potter's Fettling Knife (cuts in both directions, no rust)
- Best for porcelain and white clay: Xiem single edge fettling knife (2.5 in flexible blade)
- Best carbon steel: Dolan DPT210 Knife (hand-sharpened high carbon steel)
- Best retractable blade: DiamondCore Pottery Knife (blade slides into the handle, replaceable)
- Best two-in-one for wheel throwers: Mudtools MudShark (folding needle plus fettling blade)
Fettling knives compared
| Knife | Blade | Steel | Flex | Typical price band | Buy |
|---|---|---|---|---|---|
| Kemper F96 Soft | 4 in (maker); 5 in (some dealers) | Tempered steel | Flexible | $8 to $10 | Check price |
| Kemper F97 Hard | Not published by the maker | Hard tempered steel | Rigid, springy | $8 to $10 | Check price |
| Xiem XST-40 | 2 in, double edge | Cutlery stainless | Flexible | $9 to $12 | Check price |
| Xiem single edge | 2.5 in, single edge | Cutlery stainless | Flexible | Not captured | Check price |
| Dolan DPT210 | Not published | High carbon knife steel | Rigid | $12 to $16 | Check price |
| DiamondCore Pottery Knife | 45 mm (1.7 in), retractable | Coated stainless, replaceable | Stiff | $24 to $30 | Check price |
| Mudtools MudShark | Fettling blade plus folding needle | Not published | Not published | $11 to $15 | Check price |
Price bands are what we saw at maker stores and US dealers in October 2026. Check the live price before you buy.
1. Kemper F96 Soft Fettling Knife: best overall
The F96 is the fettling knife most class kits and studio tool walls are built around, and the reasons are simple: it is cheap, it does every knife job a beginner needs, and it is easy to replace if it goes missing. Kemper describes it as a softer steel blade that is meant to bend, used to trim pour hole waste, remove mold marks, and carve and sculpt ceramics and greenware.
That flex is the point. A flexible blade can follow a curved surface when you shave a seam off cast ware, and it gives a little when you cut a slab against a ruler. Kemper lists a 4 in blade and an 8 in overall length with a hardwood handle.
Source conflict: Kemper's own F96 page lists a 4 in blade, while The Ceramic Shop and Potter's Shop describe a flexible 5 in tempered steel blade. Both agree on the 8 in overall length class. Measure before you buy if blade length matters to you.
- Blade: 4 in (Kemper); 5 in (dealer listings), flexible tempered steel
- Overall length: 8 in
- Handle: hardwood
- Maker SKU: F96 (sold loose or packaged)
- Uses (maker): trim pour hole waste, remove mold marks, carve and sculpt greenware
Pros
- Very low price band
- Flexible blade follows curves
- Easy to find at US dealers
Cons
- Plain steel can rust if left wet
- Blade length listed differently by maker and dealers
Who should skip it: potters who mostly cut thick, firm slabs and want a dead straight cut. The rigid F97 or a Dolan knife bends less.
2. Kemper F97 Hard Fettling Knife: best rigid fettling knife
The F97 is the stiff twin of the F96. Kemper lists the same jobs (trim pour hole waste, remove mold marks, carve and sculpt) but with a hard tempered steel blade that has a springy feel, closer to a traditional fettling knife. A harder blade holds its line when you push through firm leather-hard clay or cut a thick slab, where a soft blade can wander.
Potter's Shop, which lists the packaged F97, says the knife is meant to spend less time being sharpened when you work highly abrasive, groggy clay. Kemper's own F97 page does not publish a blade length or handle material, so we list those as not published by the maker.
- Blade: hard tempered steel, length not published by the maker
- Feel: rigid with spring (maker)
- Maker SKU: F97 (sold loose or packaged)
- Uses (maker): trim pour hole waste, remove mold marks, carve and sculpt
Pros
- Stiffer blade cuts straighter in firm clay
- Same low price band as the F96
- Holds up on groggy clay per the dealer
Cons
- Less forgiving on curved cast seams
- Kemper does not publish blade size
Who should skip it: slip casters who spend most of their time shaving seams on curved molds. The soft F96 follows those curves better.
3. Xiem XST-40 Potter's Fettling Knife: best stainless, double edge
Xiem makes its potter's knife from high-grade cutlery stainless steel, so it shrugs off the wet bucket better than a plain steel blade. The XST-40 has a short 2 in blade with two flexible edges, which Clay-King describes as useful for cutting and smoothing stoneware in both directions, cutting slabs, removing mold marks from cast greenware and leveling uneven surfaces.
A double edge means you can pull the knife toward you or push it away without flipping it in your hand, which helps when you trim a seam on a pot that is sitting on a banding wheel. The oval handle gives more grip than a thin round dowel when your hands are slippery.
- Blade: 2 in, double edge, flexible
- Steel: high-grade cutlery stainless
- Handle: oval
- Overall length: not published
- Best on (dealer): stoneware clay bodies
Pros
- Stainless resists rust
- Cuts in both directions
- Oval grip
Cons
- Short 2 in blade is slow for long slab cuts
- Double edge needs care when you pick it up
Who should skip it: hand-builders who cut big slabs often. A longer Kemper blade reaches further in one stroke.
4. Xiem single edge fettling knife: best for porcelain and white clay
Xiem's single edge knife (dealer code TXKSE at Pottery Supply House) shares the same cutlery stainless steel and oval handle as the XST-40, but with a longer 2.5 in blade and one flexible edge. Xiem and its dealers pitch the single edge version for delicate white clay bodies such as porcelain, where you want a controlled cut and a blunt back to rest a finger on.
The Ceramic Shop also lists a "Potter's Fettling Knife" with a 2.5 in single edge stainless blade and an oval handle, which appears to be the same design sold under a generic name. We could not capture a US price for this exact model when we checked, so look at the live listing.
- Blade: 2.5 in, single edge, flexible
- Steel: high-grade cutlery stainless
- Handle: oval
- Uses (dealer): remove mold marks, level uneven surfaces, cut slabs
Pros
- Safer single edge with a spine for your finger
- Stainless
- Suits fine-grained clay
Cons
- US price not captured in our check
- Shorter than a classic Kemper blade
Who should skip it: anyone who works only coarse, groggy stoneware. The rigid Kemper F97 or Dolan handles that better.
5. Dolan DPT210 Knife: best carbon steel
Dolan Tools hand-makes its knives from high carbon knife steel with a hand-sharpened edge and a lathe-turned hardwood handle. The DPT210 is the rigid version; Dolan also makes the DPT220 in flexible straight and curved blades. Carbon steel takes a keener edge than stamped stainless and can be resharpened many times, which matters if you carve detail or cut clean bevels.
The tradeoff is care. Dolan tells owners to store the knife dry, the way you would store a good kitchen knife. When we checked in October 2026, Krueger Pottery Supply showed both DPT220 versions sold out, so supply can be patchy. If you want to know more about the brand, see our Dolan pottery tools page.
- Steel: high carbon knife steel, hand-sharpened
- Blade: rigid; length not published
- Handle: lathe-turned hardwood
- Related model: DPT220 flexible (straight or curved), about $39 at Krueger, sold out when checked
- Care: store dry
Pros
- Sharpest edge of the group when kept up
- Resharpenable for years
- Handmade in the US
Cons
- Rusts if left wet
- Blade size not published
- Stock is uneven
Who should skip it: anyone who leaves tools in the slop bucket overnight. Pick a Xiem stainless knife instead.
6. DiamondCore Pottery Knife: best retractable blade
The DiamondCore Pottery Knife is not a classic fettling knife shape, but it does the same jobs on leather-hard clay. Its coated stainless blade slides out of a hardwood handle and locks with a thumb screw, then slides back in for storage. DiamondCore tells owners to store it with the blade fully retracted and away from children, which is a real plus in a shared home space.
The blade is 45 mm (1.7 in) and replaceable, the handle is 13.5 cm (5.3 in), and the knife is about 18 cm (7 in) long when fully extended. DiamondCore lists it for cutting leather-hard clay, wax and other soft materials. It matches the DiamondCore needle tool, so the two can share a tool roll.
- Blade: 45 mm (1.7 in), coated stainless, replaceable, extendable
- Handle: hardwood, 13.5 cm (5.3 in)
- Overall: about 18 cm (7 in) extended
- Lock: adjustable thumb screw
- Clay state (maker): leather hard
Pros
- Blade hides away for safe storage
- Replaceable blade
- Matching needle tool
Cons
- About three times the price of a Kemper
- Stiff blade does not flex around curves
Who should skip it: slip casters who need a flexible blade for curved seams. A Kemper F96 is better at that and costs less. See our DiamondCore pottery tools page for the rest of the range.
7. Mudtools MudShark: best two-in-one for wheel throwers
The MudShark puts two wheel tools in one body: a needle for trimming uneven rims and a fettling knife edge for cutting away the waste clay at the base of a pot. Mudtools says the needle is sharp and will bite, so it folds away when you are not using it. For a thrower who keeps losing a separate needle tool and knife in the splash pan, that is a neat answer.
Mudtools sells it in six handle colors (dark blue, light blue, green, yellow, orange and red) and warns that colors may be substituted. The maker does not publish blade length, needle gauge or materials, so we cannot compare it on those numbers.
- Tools: folding needle plus fettling knife edge
- Maker SKU: MT-12-06 (color suffix)
- Dimensions and materials: not published by the maker
- Colors: six options
Pros
- Two tools you use at the wheel in one
- Needle folds away
- Bright colors are easy to spot in slip
Cons
- No published blade size or steel type
- Not a long slab-cutting knife
Who should skip it: hand-builders and slip casters who need a longer blade for slabs and seams. A Kemper F96 is the better fit.
How to choose a fettling knife
All fettling knives cut clay. The differences that matter are blade flex, steel, length and how you will store it. Think about the job you do most, then pick the knife that suits it.
Soft or hard blade
A soft (flexible) blade bends to follow a curve, which is what you want when you shave a seam line off a slip-cast form or smooth the edge of a slab. A hard (rigid) blade holds a straight line through firm clay and is the better choice for cutting thick slabs or carving bevels. Kemper sells both versions at the same price, so some potters keep one of each.
Blade length and edge
Longer blades (around 4 to 5 in on the Kemper knives) cut a slab in fewer strokes. Short blades (2 to 2.5 in on the Xiem knives) give more control for small trims and detail. A double edge cuts in both directions; a single edge leaves a blunt spine you can press with a finger, which many beginners find safer.
Stainless or carbon steel
Stainless knives such as the Xiem models resist rust when you forget them in a wet tub. Carbon steel knives such as the Dolan DPT210 take a sharper edge and can be resharpened again and again, but they need to be dried and stored dry. Plain tempered steel knives like the Kempers sit in between: cheap enough to replace if they rust.
What clay state you cut
Fettling work happens on soft to leather-hard clay and on damp cast greenware. DiamondCore, for example, lists its knife for leather-hard clay only. Cutting bone-dry ware chips edges and raises dust, so time your trimming before the piece dries out.
Slip casting needs
If you cast pots in plaster molds, the fettling knife is the main finishing tool: you trim the spare clay from the pour hole, then shave the seam line where the mold halves met. A flexible blade and a damp sponge are the usual pair. Our slip casting guide walks through the full process.
Safe storage
Fettling knives are pointed and can cut skin, so store them point down in a tool roll or a pocket of a pottery tool bag, not loose in a bucket. A retractable knife or a folding tool like the MudShark is a good idea in a home with kids.
Clay dust safety: dry clay and dry trimmings contain silica. Fettle while the clay is still damp where you can, clean up with a wet sponge or mop, and never dry sweep. If you scrape dry greenware, work over a damp towel and wear a NIOSH-approved respirator. See our clay dust safety guide.
How to use a fettling knife
- Work on clay that is soft to leather hard. For cast pieces, wait until the piece releases from the mold and holds its shape.
- To cut a slab, lay a straight edge on the clay and hold the knife upright so the cut wall stays square. Use several light passes instead of one hard push.
- To trim a pour hole, hold the blade flat against the rim of the mold and slice away the spare clay in one smooth stroke.
- To remove a seam, hold the blade at a low angle and shave the ridge in thin strokes, then smooth the area with a damp sponge.
- Rinse and dry the knife after each session. Oil carbon steel lightly before storage.
Do not use a fettling knife as a pry bar to lift pots or open lids on glaze jars. The thin tip snaps or bends, and a bent tip tears clay instead of cutting it.
Fettling knife vs craft knife and needle tool
A hobby craft knife cuts clay, but its short blade is not made to flex along a curve, and it dulls quickly on gritty stoneware. A needle tool is better for trimming a wobbly rim on the wheel, scoring, and checking how thick a base is. Most potters own both a knife and a needle; see our needle tool guide for those picks. If you trim feet, a loop tool does that job better than a knife, as covered in our pottery trimming tools guide.
Sources: Kemper Tools product pages for the F96 Soft Fettling Knife, F97 Hard Fettling Knife and PRO Needle Tool; Mudtools MudShark product page; DiamondCore Tools Pottery Knife product page; dealer listings at The Ceramic Shop (Kemper KF96, Potter's Fettling Knife single edge), Potter's Shop (Kemper F97 packaged), Armadillo Clay (Kemper F96 and F97), Clay-King (Xiem XST-40), Pottery Supply House (Xiem single edge TXKSE), Krueger Pottery Supply (Dolan DPT220) and Reach (Dolan DPT210). Specs checked October 2026.