need some help with NC Tool Knifemaker

[Dan Rice]

Last weekend I made my first attempt at trying to forge weld. I've been wanting to learn for quite a while, with the intention of working my way up to welding up some billets eventually. I decided to start by trying a few chain links. Out of five links that I attempted, I may have gotten one to stick. Couldn't knock the joint apart with a hammer like the other four, so it might have actually welded, but I'm not sure. It seemed like the forge was not getting hot enough.

 

I've read elsewhere about people forge welding billets at 5 psi with the same forge, but mine was just not getting there. I cranked it up to 15 and left my steel pieces under the back burner for a good 15-20 minutes, but they never got to anything that looked like a welding temperature to me, a middling to bright orange at best, while inside the forge. I was hoping to see the yellowish, wet-looking surface that I've seen described so often, but no luck. Also, the front burner is definitely not as hot as the rear one. When I bought the forge 8 years ago, it came with a paper that described how to set up and tune the burners, but I have long since lost it and can't find any info online about tuning it.

 

After reading the pinned "Buying a Gas Forge?" thread, I'm realizing that NC Tool forges and atmospheric burners in general are not the best way to go. I'm starting to look into building my own blown burner forge, but in the interest of working with what I've got in the meantime, I was hoping that someone out here might also have an NC Tool Knifemaker and could give me some tips on getting it to run better.

[Dennis Mitchell]

Dan, I have one as well, gets me to welding temps, but it's only about 2 years old. Had read on another thread/forum someone having the same issue as you, with one burner not working up to par. He unbolted the jet bar and cleaned some rust out of the jets and the square bar, and that fixed his issue. I don't have a booklet for mine either, but I hear they are easy to work with if you give them a call.

[J Broddrick]

Do you know what steel the links were? It may just not have wanted to weld to itself. My first forge welding was done at relatively low temps (~2000F) but it was .25 in square 1018 welded to .25 square W1. Some steels, especially low carbon, don't stick well to themselves while things like high and low carbon stick fairly easily.

[dragoncutlery]

also some times when you crank up the psi in a ventury u can create a cool spot from running rich off to the side might be a bit hotter than under the flame

[Dan Rice]

Dan, I have one as well, gets me to welding temps, but it's only about 2 years old. Had read on another thread/forum someone having the same issue as you, with one burner not working up to par. He unbolted the jet bar and cleaned some rust out of the jets and the square bar, and that fixed his issue. I don't have a booklet for mine either, but I hear they are easy to work with if you give them a call.

I'll give that a try, it's pretty likely that there's some rust in there.

[Dan Rice]

J Broddrick, on 17 Sept 2014 - 01:16, said:

Do you know what steel the links were? It may just not have wanted to weld to itself. My first forge welding was done at relatively low temps (~2000F) but it was .25 in square 1018 welded to .25 square W1. Some steels, especially low carbon, don't stick well to themselves while things like high and low carbon stick fairly easily.

The steel was some type of mild steel, which I've heard is somewhat hard to get to stick to itself. For my next experiment I'll try a piece of 1080 and see what it does. Edited September 17, 2014 by Dan Rice

[Paul Estes]

LOL I am not laughing at the situation I am laughing because when I saw NC my first thought was Numeric Control Tool Knifemaker....

[Mark Green]

Dan........ I have a 3 burner NC tool. I had to crank it up to at least 10 psi to weld modern steels, as it got older, near 20.


To weld bloom in it I had to reshape the whole interior to like a football shape, where all the burners would move to the middle.
That works great for welding temps until I fill it with slag, then I just scrape/chisel a bunch of crap out, and use my smelting stack clay as a new liner.
Then carry on.

Oh, and I removed the door, and made a fire brick wall, that I can move as I like. Lined with clay of course.

I want a forced air as well. Just for bloom welding. I have 2, 1in. T-Rex burners that will be my new sword forge.

[GEzell]

 

To weld bloom in it I had to reshape the whole interior to like a football shape, where all the burners would move to the middle.

That works great for welding temps until I fill it with slag, then I just scrape/chisel a bunch of crap out, and use my smelting stack clay as a new liner.

Then carry on.

That's brilliant Mark. I have a 'whisper momma' that is due an overhaul, I might just go ahead and completely change the interior while I'm at it to a more oval shape with clay and kaowool. It's not a perfect forge by any means, but I've had it since 1994 and it refuses to die no matter how badly I treat it.

[Dan Rice]

It seems that my problems with the forge might have worked themselves out. I took the burners apart, poked around in the orifices with a piece of guitar string, and put it back together. When I fired up the forge, it seemed to be the same, front burner still not doing much. But later on in the forging session it seemed to clear out, and the heat evened out throughout the forge. A couple of forging sessions later, I noticed that it seemed to be running hotter. So while I was working on a blade tonight, I tossed in one of my failed mild steel chain links. It got up to what looked like a welding heat to my inexperienced eye, so I dunked it in some borax, got it back up to heat, and gave it a whack. It didn't weld, but the flying sparks looked right. I'll experiment some more with a simple weld on some clean high carbon steel, and if it sticks then I guess I can't blame the forge anymore.

[David Einhorn]

I have a Whisper Momma that I purchased almost 30 years ago. It's fine for small non-knife stuff,.... but my plan is to build a couple of gas forges that are more specialized in their efficiency and higher temperature ability for knives. The advice that I have received, is that if you are going to make a lot of one type of item, such as a knife, in a gas forge, then you might wish to make or have a gas forge specifically designed for that type of item to maximize its efficiency in how is uses gas, as well as how well it heats that type of project.

 

Yes, I could probably crank up the Whisper Momma to forge weld knives, but think of how much fuel it will then be consuming.

Edited October 30, 2014 by David Einhorn