HT oven & oil recommendations needed

S

steelerfan88

Well-Known Member
I am going to start working with O1 exclusively and need suggestions on two thing :
1. Best HT oven under $1000 ?
2. What quenching oil is optimal for O1 ?
 
The first question would benefit from a bit more information. For starters... How large are the knives you make, or intend to make in the future? Do you forge, or strictly stock removal?

As for the second question, there are several good quenchants suitable for O1. I have had good luck with the McMaster 11 second oil.

Others, please chime in.

-Kurt
 
Kurt Krueger said:
The first question would benefit from a bit more information. For starters... How large are the knives you make, or intend to make in the future? Do you forge, or strictly stock removal?

As for the second question, there are several good quenchants suitable for O1. I have had good luck with the McMaster 11 second oil.

Others, please chime in.

-Kurt
Click to expand...

Thanks for the reply Kurt. I am doing stock removal only. I have no plans to forge. I am doing knives under 13" so I do not need a deep oven.)
I plan on working primarily with O1 and maybe D2 and A2 in the future.
 
steelerfan88 said:
Thanks for the reply Kurt. I am doing stock removal only. I have no plans to forge. I am doing knives under 13" so I do not need a deep oven.)
I plan on working primarily with O1 and maybe D2 and A2 in the future.
Click to expand...

If you are serious enough to buy an oven, determine the largest size you might need, then get the next larger. If you're willing to spend near a grand, then some over should not be a real problem. I use Parks AAA oil for 01, but as said, any oil in that cooling range will be fine. 01 is not too picky as long as the oil is not too fast. But even at that, I know of some using fast oils with "apparent" good results.
 
For O1, an HT oven does not really seem necessary. There's no particular ramp requirement so all you really need is to be able to soak at the Austenitizing temperature you choose.

With a good burner that incorporates progressive air:fuel ratio adjustment, a gas forge is able to provide the temperature control needed. Fire it up, adjust to temperature and put the blade(s) in.

The need to make the initial adjustments manually probably rules a gas forge type HT setup out for the pros: too much fiddling about time that could be better spent doing something that makes money. For the guys treating small batches though, not needing to open the door for each blade, and then wait for the temperature to rebound before taking out the next, could be useful. The workpiece access is through the exhaust hole, so taking out one blade does not affect the temperature of those remaining.

I have built HT ovens and HT forges. I'd use one of the forges over one of the ovens for O1 every time (though not for stainless). The gas setup can run with a reducing flame and this helps to reduce both scale and decarb. It's certainly not a complete solution (PBC or similar still helps), but it's better than an electric oven with air in it.

A 4-minute video (not mine) of a gas forge I built specifically for O1, soaking at temperature. It's not exactly enthralling, but the point is that the temperature doesn't vary very much.

816 degC is 1500.8 degF. 818 degC is 1504.4 degF.

https://www.youtube.com/watch?v=1xvWkXBXY6U&feature=youtu.be

The burner in the video uses a commercially made Venturi mixer, but a blown burner can give similarly stable and progressive control.

Cost of the entire setup came in under 150 GBP: the equivalent of $225, excluding the 10" stainless pipe used for the forge shell, but including the thermocouple and pyrometer. If the 10" pipe had not been in my scrap pile, I would have used a 25-litre drum instead, or even that old standby, an old Propane cylinder.

O1 Ground Flat Stock is readily available here and little else is, so it tends to be used as a beginner steel despite not being as easy to HT as some other steels.

I was trying to build something that "anyone" can build and get decent results with, using only parts available here in the UK.
 
I think an oven will be a better fit for me. Once I buy an oven, I can HT anything I need to and have total, accurate temp control. I would rather just spend the money once and get it right from the start.
 
Timgunn, your setup is pretty nice, why do you think it wouldn't be suitable for stainless?
Actually mine is quite similar except i have 2 ports for the venturi burners, and i use 2 for forging and ht stainless, and one for ht carbon, simply removing one of the burners and plugging a tuft of ceramic fibre in its port. Also i have a gauge at the bottle and each burner has a needle valve.
I can confirm that if we allow the whole forge to get to temperature, this setup is able to stay within a few degrees very steady. An improvement is to get a bigger bottle since if the gas starts to freeze the pressure drops and temp goes down.
My chamber is a bit smaller than yours, i get 815°C at 0,8 Bar
 
steelerfan88 said:
I think an oven will be a better fit for me. Once I buy an oven, I can HT anything I need to and have total, accurate temp control. I would rather just spend the money once and get it right from the start.
Click to expand...

i would buy this or something similar, http://www.bigceramicstore.com/olympic-139fle-electronic-controller.html. with a top temperature of 2250F you should be able to HT almost anything. would work well for any knife up to 14", has a basic automatic temperature control, uses 120Vac so it will plug in any wall, and $835 delivered is right in your price range.
 
Most 120V ovens are notoriously slow to come up to the high temps. Hours compared to minutes from the complaints I've read. I have an Evenheat 220V, and even it takes a while to come up to 1475° and even out. I think less than an hour, but don't remember exactly.
 
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The EvenHeat KH18 120V is almost as fast as the 220V model to get to the 1500F range. It's true that stainless takes considerably longer, but it still works just fine. If all you have is 120V, these kilns will do the job for you. If you need faster speeds, the new 220V KO models are way more than just higher temperature. They cut process times by 1/3. REALLY efficient!
 
stezann said:
Timgunn, your setup is pretty nice, why do you think it wouldn't be suitable for stainless?
Actually mine is quite similar except i have 2 ports for the venturi burners, and i use 2 for forging and ht stainless, and one for ht carbon, simply removing one of the burners and plugging a tuft of ceramic fibre in its port. Also i have a gauge at the bottle and each burner has a needle valve.
I can confirm that if we allow the whole forge to get to temperature, this setup is able to stay within a few degrees very steady. An improvement is to get a bigger bottle since if the gas starts to freeze the pressure drops and temp goes down.
My chamber is a bit smaller than yours, i get 815°C at 0,8 Bar
Click to expand...

I think it will handle stainless, having seen what Mark is getting out of it.

I'm pretty sure Mark is running at a fixed 20 PSI and doing all the temperature adjustment on the air gap; varying the fuel:air mixture, not the gas flow. It's what I did when I was doing my initial testing.

With the adjustable air gap, I prefer a single burner to avoid the problem of balancing multiple burners.

The gas jet is 0.5mm (0.020") as close as I can measure, so uses about half the gas a .023" MIG tip would at the same pressure (I have measured the holes in MIG tips at, typically, .006" over the nominal wire diameter).
 
the main advantage to an electric furnace is that you can use it rain or shine, 24/7/365. you do not want to use a gas forge in an enclosed space.
 
Good point Scott,
i do, and i'm not too confortable even if i provide an open window and an open door. With this in mind during the waiting time i'm out of the door, and when i finish i leave the shop opened to refresh the air.
Definitely a thing not to be understimated.
 
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