Updated October 2026 · By the Peach State Pottery team
The short answer
Knife ovens come in four layouts, and the layout matters more than the brand:
- Horizontal front-loader — the default. A box you slide blades, billets and tooling into. Most models, widest price range, most flexible. Start here: Evenheat LB 18, $2,696.39.
- Vertical air bath — a tall chamber the blade hangs in, touching nothing. Dramatically cheaper per inch of blade length, and the cheapest sane way to handle anything over 30". Start here: Jen-Ken Vertical Air Bath 21, $1,829.00.
- Salt bath — molten salt instead of hot air. Faster to temperature, no oxygen, less scale. A second oven, not a first one: Evenheat 709, $3,028.19.
- Tempering-only — 600°F–1,200°F. Cannot harden steel. Buy one only when you already own a hardening oven and are tired of waiting for it to cool.
Cheapest oven in our catalog that will actually harden steel: the Jen-Ken Vertical Air Bath EDC at $1,505.00 — 2,200°F, blades to 12", and it plugs into a normal 120V outlet.
First, the thing almost everyone gets wrong
Paragon sells two families of knife oven: the KM Base line and the Double Barrel line. The name suggests two chambers — one at hardening temperature, one at tempering temperature, so you never wait for a cool-down.
It isn't. A Double Barrel is one chamber that is wider and taller than the Base model of the same depth. Our own Double Barrel KM18 page puts it plainly:
The Double Barrel keeps the 18-inch depth of the standard KM18 but has one wider, taller chamber, so you can heat treat more blades per cycle or fit wider pieces. It is still a single chamber with one single-zone controller, so all blades in a load run the same program. If you want to harden and temper at the same time, you would need a second oven.
So the Double Barrel premium buys you batch size and clearance, not a second thermal zone. On an 18" chamber that premium is $567.00 ($3,165.75 → $3,732.75). On a 24" chamber it is $1,039.50 ($3,591.00 → $4,630.50). Worth it if you are running multiple blades per cycle or wide camp-knife and cleaver stock. Not worth it if you harden one blade at a time.
If what you actually want is hardening and tempering at once, the honest answer is two ovens — and the cheap half of that pair is a tempering oven, covered below.
Layout 1: horizontal front-loaders
A rectangular chamber with a door on the front or the side. You lay the work on the floor of the chamber or on a rack. This is what most people picture, and for most shops it is the right call: you can heat treat blades, normalize billets, run tooling, and lay flat stock down without rigging anything.
The spec that decides the purchase is chamber depth. Our KF 36 Extreme page gives the rule of thumb: plan for blade or billet length a few inches shorter than the chamber depth. A 14" Paragon KM14 is listed as taking a 13" blade.
Horizontal ovens we stock, by chamber depth
Our prices as of October 2026. Freight is additional — see shipping.
| Model | Chamber | Max temp | Power | Our price |
|---|---|---|---|---|
| Evenheat Cube 7 | 7" × 7" × 7" | 2,350°F | 120V, 12A | $2,532.60 |
| HotShot HS-1200K | 12"D × 10"W × 10"H | 2,200°F | 240V | $2,588.25 |
| Evenheat HT-1 | 13.5"D × 13"W × 13.5"H | 2,000°F | 240V, 18A | $3,624.59 |
| Evenheat KH 414 | 13.5"D × 6.5"W × 4.25"H | 2,200°F | 120V, 13A | $2,763.59 |
| Paragon KM14 | 14" deep (13" blade) | 2,350°F | 120V or 240V | $3,118.50 |
| Evenheat LB 18 | 18"D × 10"W × 6.25"H | 2,200°F | 240V, 13A | $2,696.39 |
| Evenheat KO 18 | 18"D × 9"W × 5.5"H | 2,350°F | 240V, 13A | $2,729.99 |
| Evenheat KH 418 | 18"D × 6.5"W × 4.25"H | 2,200°F | 120V, 13A | $2,822.39 |
| HotShot HS-18K | 18"D × 6.5"W × 4.5"H | 2,200°F | 120V or 240V | $2,333.10 |
| Paragon KM18 | 18" deep (18" blade) | 2,350°F | 120V or 240V | $3,165.75 |
| HotShot HS-24K | 24"D × 8"W × 7"H | 2,200°F | 240V, 20A | $3,092.25 |
| Paragon KM24 | 24" deep | 2,350°F | 240V | $3,591.00 |
| Evenheat KO 27 | 27"D × 9"W × 5.5"H | 2,350°F | 240V, 15A | $3,070.19 |
| Evenheat LB 27 | 27"D × 10"W × 6.25"H | 2,200°F | 240V, 15A | $3,057.59 |
| Evenheat KF 36 Extreme | 36"D × 10"W × 6.25"H, dual end doors | 2,200°F | 240V, 30A | $5,098.80 |
| Paragon KM36 | 36" deep | 2,350°F | 240V | $4,252.50 |
| Paragon KM45 | 45"D × 5.5"W × 4.3"H | 2,350°F | 240V | $5,008.50 |
Two things to notice. First, the 120V models stop at around 18" of depth — past that you need a 240V circuit, and that is an electrician's job before the oven arrives. Our electrical requirements guide covers what each plug type needs.
Second, depth gets expensive fast in a horizontal oven. The KM45 gives you 45" of chamber for $5,008.50, which is about $111 per inch of usable length. Hold that number.
Layout 2: vertical air baths
The blade hangs from the top of a tall chamber — by a pin, a spring clasp or a ceramic rod — and touches nothing while it soaks. The Jen-Ken Vertical Air Bath 30 page makes the case in one sentence:
A blade lying flat on a shelf touches something, and everywhere it touches cools differently from everywhere it does not. That is where warp and decarb patterns come from. In an air bath the blade hangs from the top of a tall chamber — by a pin, a spring clasp or a ceramic rod — and nothing is in contact with the steel while it soaks. Heat reaches it from every side at once, tip to tang.
Whether that matters to you depends on what you make. For a 4" EDC blade it is a refinement. For anything long and thin it stops being a refinement, because long thin steel lying on a shelf is exactly what warps.
Vertical ovens we stock
The six Jen-Ken models are all 2,200°F, top-loading, Orton AutoFire AF4X controller, blades suspended. Our prices as of October 2026. Note that Paragon does not publish a maximum temperature for the KM25 anywhere we can find, so we have not printed one — ask us and we will confirm it with the factory.
| Model | Chamber | Takes a blade up to | Power | Our price | Per inch |
|---|---|---|---|---|---|
| Jen-Ken EDC | 8" × 8"W × 13"D | 12" | 120V, 15A (NEMA 5-15) | $1,505.00 | $125 |
| Jen-Ken 16 | 11"W × 16"D | 15" | 240V, 15A (NEMA 6-20) | $1,736.00 | $116 |
| Jen-Ken 21 | 11"W × 21"D | 20" | 240V, 22A (NEMA 6-30) | $1,829.00 | $91 |
| Jen-Ken 30 | 11"W × 30"D | 29" | 240V, 26A (NEMA 6-30) | $2,408.00 | $83 |
| Jen-Ken 30+9 | 11"W × 39"D | 38" | 240V, 33A (NEMA 6-50) | $2,861.00 | $75 |
| Jen-Ken Excalibur | 11"W × 50"D | 50" | 240V, 39A (NEMA 6-50) | $3,571.00 | $71 |
| Paragon KM25 Vertical Base | 11" dia. × 25" deep | — | 240V (NEMA 6-20R) | $3,307.50 | — |
That last column is the point. A vertical air bath buys roughly $71–$91 per inch of blade capacity once you are past 20"; a horizontal oven of comparable length runs around $111–$118. The Excalibur will hang a 50" blade straight for $3,571.00. The nearest horizontal answer, the 45" KM45, is $5,008.50 and the blade lies flat.
What you give up. A vertical oven is a tall, narrow tube. You cannot lay a billet flat in it, you cannot stack shelves, and you cannot put a wide piece in sideways. It is a single-purpose blade machine. It also needs vertical headroom above the lid and a way to reach in from the top, which matters if your bench sits under a low shelf. If you normalize your own billets or do any work that isn't a blade, a horizontal oven is the more useful box.
Jen-Ken also declines to publish breaker sizes, wire gauges or temperature-uniformity figures, and says so on the page. We would rather tell you that than make a number up. If you need a uniformity spec for a certification or a customer requirement, call us and we will ask the factory.
Layout 3: salt bath
Instead of heating the blade in air, you lower it into a pot of molten salt that is already at temperature. Our Evenheat 709 page describes what changes:
Because the salt is already at temperature, the steel comes up to heat almost instantly and soaks in a consistent, oxygen-free environment — which means less scale, less decarburization, and more even hardness than many air ovens can deliver.
| Model | Chamber | Salt pot capacity | Power | Our price |
|---|---|---|---|---|
| Evenheat 709 | 7"W × 7"L × 9"D | to 5.5" OD, 16" deep | 120V, 18A | $3,028.19 |
| Evenheat 718 | 7"W × 7"L × 18"D | to 5.5" OD, 25" deep | 240V, 18A | $3,259.19 |
| Evenheat 818 | 8"W × 8"L × 18"D | to 6.5" OD, 25" deep | 240V, 30A | $3,509.10 |
All three max out at 2,000°F, which is below the 2,200°F–2,350°F the air ovens reach. For most carbon and tool steels that is plenty; for high-alloy stainless austenitizing in the 2,050°F–2,150°F range it is not. Check your steel against our heat treating temperature guide before you choose a salt bath.
Two practical warnings, both from Evenheat's own pages. The salt pot is sold separately — the oven price above is the furnace, not a working salt setup. And molten salt is genuinely hazardous: splash and steam-explosion risk from wet steel or wet tools is real, and PPE, dry tongs and dry workpieces are not optional. This is a deliberate, informed second oven for someone who already knows how they heat treat. It is not a first purchase.
Layout 4: tempering-only ovens, and the trap at the bottom of the price list
The cheapest item in our knife oven collection is the HotShot HS-360T at $1,352.40. It is also the one most likely to be bought by mistake, because it tops out at 600°F. It will temper. It will not harden anything, ever. Neither will the Evenheat LT series, which stops at 1,200°F.
| Model | Chamber | Max temp | Power | Our price |
|---|---|---|---|---|
| HotShot HS-360T | 6"W × 10"D × 6"H | 600°F | 120V | $1,352.40 |
| Evenheat LT 18 | 18"D × 10"W × 4.25"H | 1,200°F | 120V, 13A | $2,809.79 |
| Evenheat LT 27 | 27"D × 10"W × 4.25"H | 1,200°F | 120V, 13A | $3,175.20 |
Here is the number that surprises people: the LT 18 costs $113.40 more than the LB 18, and the LB 18 reaches 2,200°F and will do both jobs. A dedicated tempering oven is not the budget option. It is a convenience purchase, and the convenience is real — you temper at 400°F in the small oven while the big one is still soaking the next batch at 1,500°F, instead of waiting hours for one chamber to come down. That is worth money in a production shop and worth nothing in a hobby shop.
If you own one oven, it should be a hardening oven. Temper in it.
Which should you buy
You make folders and EDC blades under 12", on a 120V shop circuit. Jen-Ken EDC, $1,505.00. It is the cheapest real hardening oven we sell, it hangs the blade, and it plugs into a wall outlet.
You make hunters and kitchen knives and want one oven that does everything. Evenheat LB 18, $2,696.39, or KO 18 at $2,729.99 if you want the extra 150°F for high-alloy steels. Both take an 18" chamber on a 240V, 13A circuit, and both will temper.
You make long blades — swords, machetes, long camp knives. Vertical, without much argument. Jen-Ken 30 at $2,408.00 for blades to 29", 30+9 at $2,861.00 to 38", Excalibur at $3,571.00 to 50".
You run batches and your bottleneck is blades per cycle. This is the one case where the Double Barrel premium earns its money. Double Barrel KM24, $4,630.50 — same 24" depth as the Base KM24, wider and taller chamber, more blades per program.
You forge your own billets as well as grinding blades. Horizontal, and pick height over length: Evenheat HT-1, $3,624.59, 13.5" × 13" × 13.5" and 1.37 cu ft. It is the only oven here with real vertical clearance for stacked or awkward stock.
You already have a hardening oven and tempering is the hold-up. Evenheat LT 18, $2,809.79. Buy it second, not first.
You want the cleanest hardening surface you can get and you know the risks. Evenheat Salt Bath 718, $3,259.19, plus a salt pot. Confirm your steel's austenitizing temperature sits under 2,000°F first.
FAQ
Does a Double Barrel oven have two chambers?
No. It is one chamber that is wider and taller than the equivalent KM Base model, with a drop door, and it runs on a single-zone controller — so every blade in a load gets the same program. If you want hardening and tempering happening simultaneously, you need two ovens.
What size knife oven do I need?
Take your longest blade and add a few inches, then match that to chamber depth. Our KF 36 Extreme page states the rule directly: plan for blade or billet length a few inches shorter than the chamber depth. A 14" chamber is a 13" blade. If you are between sizes, go up — the cost of the next size is always less than the cost of the oven you outgrow.
Is a vertical kiln better than a front-loader for knives?
For blades specifically, it has a real argument: nothing touches the steel while it soaks, so heat reaches it from every side and the contact points that cause warp and uneven decarb aren't there. It is also much cheaper per inch of length. But it only does blades — no flat billets, no shelves, no wide pieces — so a front-loader is the more versatile single oven.
Can I temper in my hardening oven?
Yes, and if you own one oven you should. Every hardening oven on this page covers tempering temperatures. The reason to buy a dedicated tempering oven is throughput, not capability: you avoid waiting for one chamber to swing between 1,500°F and 400°F.
What circuit does a knife oven need?
The 120V models here draw 12–15A and run on a normal household outlet, but they stop at roughly 18" of chamber. Past that you are on 240V, drawing 13–39A depending on size, with NEMA 6-20, 6-30 or 6-50 receptacles. Get the circuit installed before the oven ships — see our electrical requirements guide.
Why don't you publish a breaker size for every model?
Because most manufacturers in this category don't publish one, and we would rather say so than invent it. Jen-Ken explicitly declines to state breaker size, wire gauge or uniformity figures. We publish volts, amps, watts and plug type, which is what an electrician actually needs, and we will ask the factory directly if your inspector needs more.
Talk to someone before you buy
This is a category where the wrong answer is expensive and the right answer takes two minutes on the phone. Tell us your longest blade, your available circuit, and whether you forge your own stock, and we will tell you which of these four layouts you want — including when the answer is the cheaper oven.
Every oven on this page ships flat-rate freight with liftgate service included, and we will match any authorized dealer's advertised price — see our price match guarantee. There is no sales tax on orders shipped outside Georgia. Veterans and first responders, check our military and first responder discount before you order.
Browse the full range in knife making ovens and heat treating ovens, try the kiln finder, or just get in touch and ask.
Related reading: Evenheat vs Paragon vs HotShot: best heat treat oven for knife making · heat treating steel temperature guide by steel type · Jen-Ken kilns explained · top-loading vs front-loading kilns · what to expect on kiln delivery day.