Custom Knife HT ovens

JTknives

JTknives

Joined
Jun 11, 2006
Messages
8,651
I have been toying with the thought of starting a small on the side bizz making HT ovens just for knifemakers. I want to make i usefull 110v oven that will come up to temp fast and will hit 2300 if needed. from what i have read, what matters in a treat oven is not the volume but the surface area of the walls and doors. if thats true then getting some numbers from the paragon km-24D is easy.

KM-24D
5.5" wide
4.25" high
24" deap
240 Volts @ 8 Amps
1800 Watts
514.75 total squar surface inches.
3.5 watts per inch^2

now the one im thinking of making would be a tad smaller but should heat faster.

JT-18
2" wide
4" high
18" deap
110 Volts @ 18.18 Amps
2000 Watts
232 total squar inches
8.62 watts per inch^2

As you can see the Watts per square inch is quite a lot greater. my question is why do you need an oven so wide. if your going to do just one blade i dont see why a smaller width would not work. of corse some testing would need to be done. any ideas
 
its just my thought why have more space then what you need. also we have forum members that make custom forges for us why not HTR ovens.
 
I have the 9" deep x 8 1/2” wide x 4 1/2” high paragon.
for some reason I try to keep the blades a couple in. away from the coils.
Is it safe to have them that close.
 
fludunlimited said:
I have the 9" deep x 8 1/2” wide x 4 1/2” high paragon.
for some reason I try to keep the blades a couple in. away from the coils.
Is it safe to have them that close.
Click to expand...

i was thinking about that. you dont want the knife to tuch and short out the coiles. i was thinking about getting the quortz tube that the coiles can go inside to protect them.

Also the size could be increased to 4"x4"x18" and still have a quick heat up time.

4" wide
4" high
18" deap
110 Volts @ 18.18 Amps
2000 Watts
320 total squar inches
6.25 watts per inch^2
 
Is it too early for estimates? It seems like making them on a small scale would be expensive.
 
For me, that would be too narrow. Knives aren't the only things I heat treat.
Also, I will often heat treat more than one blade at a time.
But I do like the idea of the greatly increased watts per square inch (actually I think we should be refering to watts per cubic inch). The fast ramp to temp times would be very nice! The faster the better. If you go with a bigger 'box' you may well need to go to 220 volt to keep the current down and still get the same watts per cubic inch.

Being able to hit 2300 deg. would be nice. That would open the door to CPM10V that needs to be ht'd at ~2150 or so. I don't want to run my Blue M oven that high for fear of burning out an element.


Just my $.02...........

-Mike-
 
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i now have unlimited axcess to such a nice shop at work that i think we could make this work. let me kick around some numbers and see if i could get a ball park cost. im thinking a small chamber for the the 110 model as people that are going to need one for 110 probabley arnt a fulltime maker and wont need to do real large blades. so even if i took the length down to 14" i think it would be ok and it would boost the ramp time quite a bit

4"x4"x14 = 256 squire inches and at 2000 watts thats 7.81 w/in^2
 
You didn't ask, but I think you're setting yourself up for too many irons in the fire.

Focus JT, focus. :)
 
I know where Nick's coming from Jarod, but maybe you're young enough to still have the energy to keep all these projects in the air. ;) That's a foreign concept to someone as ancient as I am. And I guess for Nick too. :D

I think your idea is a good one. I bought a much larger HT oven because I wanted to do some rather long blades, and I was right - I used all the length available to me in my first knife back out. And I've used my oven for glass etc too, which needs the width. But I agree that most of us part timers would be okay with HTing one knife at a time, and it'd be nice to ramp up quickly.

Are you thinking about including a controller, or making this a manual control oven? Everyone bitches about the Set-Pro at first, but once you get the hang of it it's not too bad. Still, I think there are controllers out there that aren't so arcane. And a single program would probably be okay if changing it wasn't a big deal. But I do enough different stuff that having multiple programs - and given what a pain in the keester programming this thing is - multiple programs is a good thing.

For what it's worth, maybe 220 isn't that big a deal. Most motors big enough to run a honkin grinder need it anyway. It didn't cost much to have 220 run to my shop.
 
ok last post then i go to bed ;)

heat chamber will be 2" wide by 4.5" tall and 18" long. it will be pumped with 2000 watts of power. to protect the blade and the ellement, the heating wire will be mounted on the top of the chamber. it will be very very easy to replace as it wont be wraped in a coil but a flat back and forth ellement that sits under the top fire brick and in a little notch on the walls. so to change it out you just take off the top steel cover by removing a few bolts and lift off the top bricks and take out the ellement and put a new one in. the elament wire will go through the brick and steel and connect to a ceramic connection block that is bolted to the steel frame. the thermal couple will be about 1.5-2" off the floor and recessed into the wall by about a .5" so it will get the temp of the blade not the top of the chamber like the other heat treat ovens. it will have a PID temperature Controller w/ Ramp/soak that has 30 programmable steps for ramp, soak and other logic actions. it will also have an Alarm that you can program to go off for what ever you want. say you want it to let you know when it hits 1900F or when the blade has soaked for 30min. it will be made from 2600F bricks and will hit 2300F as the wire is rated to Temperatures of 2350°F. now i did some math and i wanted to see what kind of watts per cubic inch of volume i would have compared to say the km-24d paragon

JT-18
4.5" x 2" x 18" = 162 cubic inches. 2000 watts / 162 cubic inches = 12.34 W/in^3

km-24d
5.5" x 4.25" x 24" = 561 cubic inches. 1800 watts / 561 cubic inches = 3.208 W/in^3

km-14d
5.5" x 4.25" x 14.5" = 338.93 cubic inches. 1200 watts / 338.93 cubic inches = 3.54 W/in^3


now that was for cubic inches. but what about square inches

JT-18
4.5" + 4.5" + 2" + 2" x 18" + (4.5" x 2") + (4.5" x 2") = 252 square inches. 2000 watts / 252 square inches = 7.93 W/in^2

km-24d
5.5" + 5.5" + 4.25" + 4.25" x 24" + (5.5" x 4.25") + (5.5" x 4.25") = 514.75 square inches. 1800 watts / 514.75 square inches = 3.49 W/in^2

km-14d
5.5" + 5.5" + 4.25" + 4.25" x 14.5" + (5.5" x 4.25") + (5.5" x 4.25") = 329.5 square inches. 1200 watts / 329.5 square inches = 3.64 W/in^2

now that should give you an idea of how fast this should be able to heat up. of corse this is just on paper and we wont know for shure till i make one but numbers dont lie. now with this size you wont beable to do very many knives at once but it should heat up fast enought that it should not matter. now the best part is that it will cheaper then the evenheat 13". now time to go to bed :yawn:
 
JT,
I am with Nick. You need to get one thing completely done and mastered before you jump to the next.
Work on the girlfriend, the new shop, the JT wrap, the girlfriend, the tang stamps,the new job, the girlfriend,the first amendment knives, the knife production, ....and spend some time with the new girlfriend. If you have too much going on to do all that....send me the girlfriend.

Some questions to ask yourself ( and others):
How long have you been using a HT oven?
How many types have you tried?
How many people have you sat down with (not E-chatted or read posts) and discussed the ins and outs of HT ovens?
How much electrical ( practical and engineering) background do you have, or understand fully?
How much thermal engineering do you understand?
How much time do you have to spend on developing this enterprise?
Why is the market not flooded with cheap Chinese HT ovens?
Why does everybody use 220V for bigger equipment?
How much space is needed? How much is too little? How much is too much space?


Building a good HT oven is more than just making an insulated box and sticking a nichrome or Kanthal coil in it.

Before you enter the oven business also consider:
The need to get business licenses, insurance with HIGH liability coverage,making at least ten or twenty test units, and several other things .....before you take the first order.

Some areas to consider in the design:
What is the largest item that the oven will HT? What shapes might it be in?
How much clearance from the sides is optimal for heat transfer and even heating?
Is 110V at 20 amps a good idea, vs 220 at 10 amps?
Safety features!!!!
Where will I build and market these ovens? ( your current boss may not want such a business opperated in his location (liability) and jobs don't always last forever.)
Is this a passing thought ,or a business idea????
How much will the development of this idea cost????
How much time will the development of this idea take from my current schedule????
Is there a profit in this idea, or just fun doing it????

Some food for thought.
Stacy
 
The dimensions aren't accommodating to most knife makers, imo. When I run a cycle, I want to be able to run multiple blades. I'd rather be limited in depth to increase width and height. Also, getting to 2300* quickly isn't really a concern, steels that heat treat that high have ramp times for the most part.

I thought about doing ovens before, until I looked at UL and other safety listings. The cheapest outfit I found to to testing said it would be $12,000 and that was for a different sticker, not even the UL one. If something happens and there's a fire in the shop, an insurance agent could deny the person's claim if the equipment is not rated (even if it's made from safety tested parts). This isn't a big deal if you make your own equipment and accept responsibility for yourself, but when you start selling these things to people you have to worry a lot more.
 
Stacy i think your the little voice of reasion thats in my head that comes pre installed in other people that some how i missed out on getting :D. What if it was a kit kind of thing that the buyer put togeather at his owne risk. And it had a chamber size of 4x4.5x9. And you could add sections on to it to make it as long as you wanted. Just an idea. Also i would give up everything on that list befor the girlfriend, sory stacy.
 
You may want to look at mass to heat rather than volume of the chamber. Most the time and power goes to bringing everything (bricks coils) up to temp while losing heat out the backside. If you optimize the mass for the given volume you can save power and heat faster.
 
maybe use the 1" thick high temp fiber refractory board used for forges. i don't need to cut out slots for the element as its going to sit on the top.
 
I looked into this seriously not that long ago. I believe there is a reason knifemaker's kilns are a side business for paragon, evenheat, sugar creek and the like.

If it's DIY then folks can simply order the parts, where is the value-add? Unless you're saving money for them, why should folks buy from you instead of building their own? Much of the savings in a DIY oven is sourcing your own parts, at a certain point it's just cheaper to buy a kiln or cheap oven and add what you need. If you're selling the kits with instructions (which are available free already) then you may also have some liability, if you're not selling with instructions then you're one point less on the value-add.

The tool supplier success story around here is Rob Frink, he's a machinist and he'd built multiple grinders and published plans and instructions on building grinders before the KMG took off. One of the reasons it was successful is because he knows what he's doing, in and out. Have you even built an oven yet?

Every couple of weeks you have some new way to make money off of people on these forums. I hope folks realize this and steer clear of you on this one.
 
AcridSaint said:
Every couple of weeks you have some new way to make money off of people on these forums. I hope folks realize this and steer clear of you on this one.
Click to expand...

Whats up with that. i mean ya i post new ideas all the time but i'm not stealing peoples money. most of the ideas i post don't work out but is that any reason not to get some other peoples input. I love making things and so my mind is going a 100 miles an hr all the time and when something comes to me i post it here. you make it sound like i'm trying to rip people off. which is not true at all i just like to get others input.
 
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