My Very First Knife

[lepepwerna]

You could use the arduino to send control voltage to a contactor, and have thethermocouple power run through the contactor. The arduino would just activate/deactivate your major circuit. Where I work we have 24 volt dc control power operating 700 hp electric motors using 4160 volt 3 phase power. Think of it as an electric computer controlled light switch.

That's an interesting way to put it. But then it would be just an On/Off type of circuit correct? There would be no way to modulate the power provided to the thermocouple. Unless that's not how they work anyway. I'll have to do a bit more research. It was mostly day dreaming anyway, I probably won't get around to building one for a long time, even if I do figure out the circuit.

 

[scubasteve4sq]

Correct it would be on off control. I assumed you were trying to control it like an oven where the burners come on and off periodically to maintain a temperature. Let me ask my electrician i work with and see if he has any ideas for modulating the power.
Can you give me some more info on the unit?
What kind of voltage/amperage does it use.
What does it use at different temperature settings?
How does the expensive controller operate it?

The only thing i can think of off the top of my head would be some sort of rheostat or potentiometer in the circuit.

 

[scubasteve4sq]

Let me say im just diving into knife making so i think i understand what the kiln process is. For example you may want 490 degrees for 2 hours and then off. On the next knife you may want 600 degrees gor 3 hours or whatever. My idea would be a rheostat which is basically a variable resistor, its just a knob you can turn to vary the resistance in a circuit. So you set your rheastat to whatever temp you want and you use the arduino as a fancy timer. Hook it up to a contactor and tell it you want it to run a 2 hour cycle.

Info on rheostats
http://www.tedss.com/rheostat/

If you wanted to get real fancy you could remove the knob on the rheostat and hook a servo motor up to it and control that with the arduino for fully automated operation but thats getting more complicated and probably approaching the same ammount of money as a store bought controller.

 

[PaMtnBkr]

For sharpening those pesky recurves, get a Spyderco Sharpmaker! Great sharpness and easy to get things hair splitting sharp! Relatively inexpensive too! BTW-Great job on your first knife!

 

[lepepwerna]

Let me say im just diving into knife making so i think i understand what the kiln process is. For example you may want 490 degrees for 2 hours and then off. On the next knife you may want 600 degrees gor 3 hours or whatever. My idea would be a rheostat which is basically a variable resistor, its just a knob you can turn to vary the resistance in a circuit. So you set your rheastat to whatever temp you want and you use the arduino as a fancy timer. Hook it up to a contactor and tell it you want it to run a 2 hour cycle.

Info on rheostats
http://www.tedss.com/rheostat/

If you wanted to get real fancy you could remove the knob on the rheostat and hook a servo motor up to it and control that with the arduino for fully automated operation but thats getting more complicated and probably approaching the same ammount of money as a store bought controller.

I'm just barely into knife making myself, I just thought if I stick with this it might be a neat project down the road. The software I found (which I now seem to have lost) would have the arduino acting as a programmable rheostat basically. If all the arduino was going to be doing was acting as a timer, I could probably rig up a timer to do the job cheaper. The only thing I could think of for controlling an external circuit is using an inductor to manipulate a switch/rheostat/potentiometer. I don't know if this is possible, I could ask some of my EE friends perhaps.

For sharpening those pesky recurves, get a Spyderco Sharpmaker! Great sharpness and easy to get things hair splitting sharp! Relatively inexpensive too! BTW-Great job on your first knife!

That Sharpmaker looks pretty good... I think I may go for it. Thanks

 

[scubasteve4sq]

I'm just barely into knife making myself, I just thought if I stick with this it might be a neat project down the road. The software I found (which I now seem to have lost) would have the arduino acting as a programmable rheostat basically. If all the arduino was going to be doing was acting as a timer, I could probably rig up a timer to do the job cheaper. The only thing I could think of for controlling an external circuit is using an inductor to manipulate a switch/rheostat/potentiometer. I don't know if this is possible, I could ask some of my EE friends perhaps.



That Sharpmaker looks pretty good... I think I may go for it. Thanks

im not sure an inductor would be able to spin the rheostat, the high voltage ones are pretty stiff and often "click" into place at each resistance setting.

just had a thought, those old red lincoln welders had a very heavy duty rheostat in them. you can pick those things up very cheap.

 

[Dan Morgan]

I'm very impressed that you made a functional folder for your first attempt at knife making! I haven't gotten into folding knives yet. For my first knife I pretty much went in blind, got myself some 1/4 inch 440c stainless, and through some trial and error got something blade shaped. I cast bronze handles and put em on. Granted the steel is hard, and it hold an edge, but if I drop it I run a risk of either chopping a toe off, or just smashing most of the bones in my foot. Keep it up! Grinding was the hardest part for me to learn.