My little "shop" and a few toys from it

Bruno

Administrator
Staff member
Putting a bevel on a fresh knife is something that goes much better on a belt sander, using a 220 grit at medium belt speed.
Just sharpen the sides alternately until you get a burr. Then take it to 1000 grit stone.
Setting the bevel on a plate is a huge time sink.
 

Shawn

Member
I've got one of those Lansky systems with the diamond stones for it. Keeps me consistent with my angles. It's definitely looking more and more like I need to use the belt grinder though. Especially with the new steel.
 

Bruno

Administrator
Staff member
My attitude to things like this is: if it is costing me ages to do something, I need to figure out a smarter way to do it.
It takes less than a minute on a 220 grit belt.

Only works for knives, not razors though :D
 

MotoMike

New Member
Bruno, do you set the bevels free hand or use a jig? On my home brew grinder, I have a tough time getting a sharp plunge line. Of course Shawns won't have that problem.

Shawn. I like that one best so far. Not a big Santoku fan as the tip is too fat to do any more precise tip work. Well done.
 

Bruno

Administrator
Staff member
I don't get the question :)
When you set a bevel you shouldn't be touching plunge lines or anything.
Yesterday I made a short video explaining what I do. I'll upload it later today to show you.
 

Shawn

Member
I like that, but the only thing that really worries me about it is that I don't have variable speed. I'm really paranoid about overheating the tip. But I guess, I do finish grind them without heating it up, so I guess it's not really a good excuse is it? Guess I'm just paranoid in general about having it that far finished and then going back to the grinder. I suppose if I just make myself do it a few times then I'll be fine with it.
 

Bruno

Administrator
Staff member
If you keep it at the right angle and don't use too fine a belt, it won't have time to heat up. A 120 grit belt creates less heat than a 400 grit belt. And it removes metal faster so heat doesn't penetrate as quickly. Also note that I don't linger. The tip makes contact and then the knife just slides from left to right without losing contact or lingering. If one spot needs a bit more work, I'll catch it on the next pass. This also keeps the knife profile clean.

You probably have a couple of shop knives lying around. Give it a try. You'll be surprised at how easy this is.
 

Shawn

Member
I did as you suggested. I went 220 ceramic belt though instead of 120. The ceramics run pretty cool for me, and I wasn't as afraid of messing up because 220 won't take as much if I do.
Worked just fine.
 

Bruno

Administrator
Staff member
Time = money :)
And I've said many times: I am not doing this 'for' the money.
But I like making knives enough that I would rather make 3 knives instead of 2 in the same amount of time.
 

Shawn

Member
I know I've been away for a while again.... Started a new job and it has been keeping me pretty busy.

I do get a few perks to this job though. I am a maintenance mechanic/welder/machinist. So I have access to a mill and lathe, as well as basic fab shop. Mike Blue has been helping me along and I've been working on a new burner for a forge build. I've machined out the orifice according to the specs he gave me and today while cleaning up some stuff outside the plant, I salvaged a piece of pipe for my new forge body.

Going to line it with 2 inches of ceramic wool and build up the bottom with the wool so that it is flat, then coat it and ceramic line it. (plistix coating)

That part is still to come, but the body of it is done at least.

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I also made a kitchen knife for a friend to use in a cooking competition that is this weekend actually. He really put it through the wringer testing it out. He told me he cut onions, tomatoes, chopped veggies, filleted a fish, cut and trimmed meat, basically did an HHT with fat off a steak he trimmed, cut up pineapple, and even shaved the bones for some lamb chops...

I asked him how many times he needed to steel it and he told me that it was all done on the original edge that I put on it for him. So I'm kind of liking the 1095. It's an absolute bear to put a final edge on, but it forges well and seems to be very durable for kitchen knives.

1020
 

Bruno

Administrator
Staff member
Cool. Access to a machine shop is a perk i could really use! A proper industrial mill would be a godsend, and impossible to have at home.
 

Shawn

Member
Got the ceramic wool ordered today. 24 inch X 4 foot roll of 2 inch thick for $38. Will be here tomorrow actually on their standard shipping. Can't complain with that.
Also got my burner pretty much done other than the orifice hole. Forgot to order the #70 drill that I needed to do that. The bottom sleeve will get welded onto the forge body for adjustment and holding. Mike says I won't need a flare for this style, so it is just heavy wall 3/4 inch pipe and the burner orifice is adjustable in the end of the mixing tube for tuning.

1021
 

Shawn

Member
Tuning this thing is getting the best of me. I either get too much of something that I can't get a flame, or I need to choke it down so much that even at 30psi I get no heat.

If I put the burner in my little forge, and keep the end about an inch inside the refractory like my other one, I get no flame just spitting and sputtering.

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If I choke the air down (close off two of the 4 holes) it starts to burn a little, but no where near like it should be.

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If I keep the air choked down and pull the burner way back into the refractory, it will burn steady, but I get no heat from it. Running it at 30psi is like running my other one around 10-15ish. It doesn't seem to have any pressure anymore. (This is all I get after having the front on it for about 4 minutes and after doing the above tinkering)

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I did get the .028 drill and drilled it to that size as @Mike Blue recommended. As far as I can tell everything is to spec. Air holes are 1/2 inch dia, 4 in total. Pipe size is 3/4 inch and 10 inches in length. Orifice size is 0.028 inch.

I thought maybe the forge was too small so I tried burning it just in the open. It won't really hold a flame at all that way. It either tries to burn back up the tube or blows itself out. I've tried adjusting the depth that the orifice is set into the tube also, but it's not making any difference that I can tell.

Any ideas?
 

Mike Blue

Member
First, I haven't seen one of this type of burner ever run well vertically. I recommend at least from the side. Heat rises so it's logical that it will try to burn back up the burner tube.

without flaring the tubing you won't get a standing flame outside the forge. Adjusting the depth of the burner into the side wall is a great idea to look at. adjusting the depth of the orifice relative to the air intake holes is also a good variable to look at. It appears you've figured out that you may have too much air to gas and have damped down on air flow. I use a piece of copper tubing that just slides down the OD of the burner with a set screw. In emergencies I've used duct tape to cover the holes by half and adjust from there rather than plugging one or two holes entirely.
 

Mike Blue

Member
These forges work best having a little "back pressure" e.g. the air/gas is blown into the forge body and the door is closed a bit to restrict exhaust giving it time to burn. Once the refractory wall heats up it will maintain self ignition better and the forge should smooth out and burn better.

An improved body style would be round and have the burner tube come in sideways at an angle to the radius rather than straight in. Ideally the flame front will swirl around the inside of the forge and eliminate that big hot spot that is going to develop opposite the burner. A uniform heat helps avoid scale and material loss. Although it's easier to assemble squarish bricks...
 

Mike Blue

Member
One of the early pictures showed a round tube...I thought that's how it would get built.

One of the other items to consider is more pressure. I've seen other builds where they just didn't seem to want to burn. I open up the regulator and the needle valve. That tiny orifice likes pressure. It's possible the liquid surface of your gas tank cannot evaporate enough gas to supply pressure. These forges will slow down when condensation develops on the side of the gas tank. Shake it up and you'll hear it ramp up again. Keep the gas bottle warm and it will run better. I had a 125 gallon horizontal pig so there was a large evaporative surface.
 

Shawn

Member
One of the early pictures showed a round tube...I thought that's how it would get built.

One of the other items to consider is more pressure. I've seen other builds where they just didn't seem to want to burn. I open up the regulator and the needle valve. That tiny orifice likes pressure. It's possible the liquid surface of your gas tank cannot evaporate enough gas to supply pressure. These forges will slow down when condensation develops on the side of the gas tank. Shake it up and you'll hear it ramp up again. Keep the gas bottle warm and it will run better. I had a 125 gallon horizontal pig so there was a large evaporative surface.
The forge it will be going into is the round one. I haven't gotten the kast-o-lite yet to coat the ceramic wool with, so I just stuck it in my little forge to see how it would burn.

I do have a steel sleeve with a set-screw that slides up and down to be able to close off some air flow. That is what I was using, so we should be good there.

I didn't get any back burn vertically, but I got it when I tried to burn it outside of the forge and it was lying on it's side. That was probably from not enough gas pressure. When I tried to turn it up it would just go out. Reading what you said, that was probably from not having sufficient back pressure then.
Possibly also why it's not burning properly in that little forge, it may be getting too much back pressure. I noticed an excess of exhaust smell that I usually don't get. So couple that with what you are saying, and I'm probably not getting the right amount of space for this particular burner to function properly. That little thing is only around 90 cu inches of internal space.

I am running on a 40 pound tank on a 30psi regulator that is currently between 1/2 and 3/4 full. So in theory, it should be down enough to evaporate sufficiently, yet provide adequate pressure.

I should be getting the castable refractory shortly, so I may just need to wait until then to try it out. Thanks for your continued help on this venture Mike.
 
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