David Ab

It's weird, because when I carried a fire extinguisher in my car, about once a year I would be driving along, see someone's car on fire, and stop and put the fire out. But then because of the expense, I stopped carrying a fire extinguisher, and in the twenty years since then, I haven't seen even one car on fire. Anyway, one time I saw a maseratti on fire (seriously, a real one), and this breathtakingly beautiful blonde girl standing by it, screaming. I pulled over, got out my fire extinguisher, got the engine compartment open, and put out the fire. She was incredibly grateful and said, "How can I repay you?" Yes, the same thing occurred to me, but for some unaccountable reason I didn't say the first thing that came to mind. Then she said, "My boyfriend's going to kill me. What can I tell him?" I said, "Storm into the house, slap him a good one, and tell him you CAN'T believe that he would give you such an unsafe car to drive." Another time, it was a cadillac on fire, and of course again it was a woman driver, with a young man- I guess her son. As I was getting the hood open, she kept screaming, in a deafeningly shrill voice, "What can I do, what can I do, what can I do?" I yelled, "Hey!!!" as loud as I could, and she stopped screaming. I said, "If you want to help, here's what you can do: just stand there and be quiet while I put the fire out." The young man was trying to hide his smile. After I got the fire out, I told the woman, "Here's how you can pay me for saving your car: take a yoga class or something, and learn to relax."

You may no longer be a youngster if you know how to do anything without using a computer. you may not be a youngster if you remember the good old days when you could deal with crooked politicians by tarring and feathering them, tying them to an inner tube, and setting them adrift in the river.

Superglues contain toxic chemicals that cause asthma and possibly other problems. It might be safer to put vitamin E on your hands, and take zinc supplements.

I believe that what you have there is what is commonly known as a "Nikon Third-Hand Beer holder," used by many Boeing machinists at baseball games. This very handy (pun intended) device allows you to hold a hot dog and a bag of peanuts while making certain that the scoundrel to your left can't steal your booze unless he has a 5 MM hex wrench. The X, Y, and Z-axis adjustments are useful for making up for whatever state of drunken revelry one might find oneself in- anywhere from your common 3-beer 2-degree X-axis tilt, to a full-case 90 degree tilt on all three axes, though the last time I saw someone with the skill to make that particular adjustment was at Molly's House of Not-so-Good Repute in Index, Washington, back in 1936. Actually, I think the other guys are right- it's for holding a microscope.

And if that doesn't work, put it in a cardboard box with birthday wrapping and ribbons and a card on it, and put it out by the street.

Robert, I have a few suggestions. First off, you were right to consult with the people who make the pain med pump- if anyone can give you a certain answer, it's them. Some electric/electronic devices put out more or different kinds of electromagnetic fields than others, and no one has put forth the effort to make a chart. But there are some things you can do, although I would ask you to check with the manufacturer of the pain med pump first. : 1. Get a gauss meter, which measures the field that's put out by many electric/electronic devices. It won't tell you for certain whether your pump will react to a particular induction oven or other device, but it will tell you something about the strength of the field of the induction oven as opposed to the fields of everyday electric/electronic devices that you know you can safely use, and that comparison could be an indicator of whether it will affect the pump. 2. Get a cheap little A.M. radio, and adjust the tuner so it's not on any particular station- so all you hear coming out of the speaker is static. Then go around your house with the radio near your belly, and approach the electric/electronic devices that you normally use, such as the toaster, electric oven, electric stove, television, DVD player, electric shaver, (and so on), with each of those devices turned on, and get as close to them as you are when you use them, and see if you hear any difference in the static that's coming out of the radio. You see, the radio antenna picks up on more than just radio waves- it also picks up on lots of the electromagnetic "garbage" fields that are put out by the devices that you use every day. Then approach an electric heat treating oven that is turned on, and see whether the static coming from your radio is louder or not as loud as it is when you're near the electric/electronic devices that you know are ok for you to use. One last suggestion: ask the pain med pump manufacturer these questions: "If my being near an electric device shuts off the pain med pump is there any way for me to tell that it's off other than when I start feeling the pain, and will it reset itself and come back on, or will it be broken?" Good luck! David Ab

Thanks, Monster. I checked out your web site, that's some sweet metalwork. David

I'd like to answer your questions about the chisel I ruined, but when I did that particularly masterful bit of work, the only thing I knew was, "Heat it real hot with a torch, then shove it into some oil and you'll never have to sharpen it again." Which has turned out to be true, because I put the chisel on a shelf and only take it out to admire it once in a while, and then I return it to the shelf... I think quenching blades is like lots of subjects, where in order to truly understand it, you might want to approach it from a multidisciplinary viewpoint. When I couldn't find the depth of information I wanted about quenching (admittedly, I didn't buy the expensive ASM books or correspond with the old masters of knifemaking...), I turned to wikipedia, physics books, and other sources, and read that there are two types of waves that earthquakes produce: Primary waves, and Secondary waves, or P waves and S waves. Then I did a search for waves and quenching, and found that S waves also occur during quenching- that the cooling effect of the quenching process moves through the steel in an S wave that forces the hot, austenitic steel to cool so quickly that it bypasses the next step in cooling and locks the steel into the martensitic stage. I think of the S wave as a shock wave because quenching certainly comes as a shock to the steel, and as the S wave moves through the steel, if it encounters a sharp edge such as a deep scratch, a sharpened blade edge, or a sudden change of dimension such as an un-radiused 90 degree angle between the blade and the tang, the sharp edge cools much faster than the surrounding metal, which induces a stress line in the steel. So, in preparing a blade for heat treat, you sand out all of the deep sanding marks and gouges, round all of the edges, round all of the sharp transitions in blade shape, and leave a 1/16" or so radius on the sharp edge rather than fully sharpening it, all of which helps prevent a thin part of the blade from getting hit with a very fast S wave that then slows down drastically when it hits a significantly and suddenly thicker part of the blade. It's that slowing down of the S wave that creates stress lines that even tempering might not be able to get out of the blade, because when the S wave moves fast and then slow, the metal crystalizes at different rates and therefore forms a physically weak boundary line between the faster-quenched part and the slower-quenched part. The other aspect of avoiding stress lines during quenching is to use a slicing, edge-first quenching motion through a big enough quench container so you can get the blade cool enough with one swipe through it, or a plunging the tip straight down, pulling it up, and plunging it straight down motion. These motions allow for a consistent vapor barrier breakdown. The speed of the vapor barrier breakdown controls how quickly heat is transferred from the blade to the quenchant. If you use a figure-eight motion on a blade, you can get an uneven breakdown of the vapor barrier and thus an uneven transfer of heat out of the knife, and thus an uneven movement of the S wave through the metal. But after studying this stuff for years, one thing has become clear: there are a lot of unknowns about metal and about heat treating. Sometimes the slightest little difference in whatever, can create a better blade or a worse blade. I don't know if those guys at the factory were kidding about figure-eighting their quench motion, but I've heard some knife makers say that some of the heat-treating methods used for massive pieces of metal in industrial applications, don't work so well for the very slight mass and the shape of a knife blade. My wife says I ramble too much and that I don't know nearly as much as I think I do. She's probably right...

Hey Ouch, I appreciate you bringing up that question, because I just tore apart an old water heater to get sheet metal to build my forge, and now I'm thinking I'll save the burner from the heater, so if I build a bigger forge I'll be able to put smaller orifices on that one and use it. David

I don't know if this is relevant to your situation, but a cousin of mine, who built houses in Dutch Harbor Alaska, told me that air leaks are worse than lack of insulation in many situations.

I don't know about cockroaches, but I got rid of a very bad infestation of carpenter ants in a house, by drilling a few holes in the walls and pumping in some boric acid. Within several days they were gone. And those were some kind of super ants, too, because a pesticide contractor had put so much ant poison around that house that the women who lived there and her dog got very sick.

I've been on the forum for awhile, just found this part of it. I've made a few knives and heat treated some of them with a torch. Had some interesting learning experiences, such as the chisel I heat treated, and then the end of the chisel fell off the first time I put it to wood... I'm getting serious about it now: building a propane forge, got some 0-1 and A-2 steel, going to learn to heat treat and hopefully make some good quality knives. And if I eventually get good at that, I might even try to learn to make damascus. I'd sure appreciate any suggestions or corrections you more experienced guys would care to offer me now or later. As a 36-year veteran of the construction and remodeling industry (retired general contractor), I've done a fair amount of woodworking. These days I'm an environmental inspector specializing in health issues- especially air quality and ventilation issues in the shop, home, and workplace, so I'd be happy to try to answer questions on that subject. David Abbot

A friend of a friend made a crossbow from used material. It shattered and a shard went right into his heart. He was dead before he hit the ground, right in front of my friend. I am not joking, but I am trying to scare you. I can sure understand wanting to make a crossbow, but if I was you I would find a highly experienced crossbow maker (not some weekend guy, but a pro) who was willing to supply the right materials and allow me come to his shop and show me how to do every step. There's lots of forging-type stuff that a beginner can do relatively safely, but this isn't one of them.

I read about a study of coal miners in Virginia, I think it was. Of the miners who smoked cigarettes, 97% got black lung disease. Of those who didn't smoke cigarettes, only about 5% got black lung. But mind you, I didn't read the actual study- this is just what I remember from something I read about 40 years ago, but I think the general idea is accurate. And I read that virtually all of the cooks for monasteries in Nepal get lung diseases from cooking over the fires. You really should have very good ventilation for your forge. I'm making a forge- should be done in a few days, and I'm getting a carbon monoxide detector- whenever the meter says there's carbon monoxide in my shop I'll know I need to ramp up the ventilation. Not that this is necessarily true for you, but a lot of "little coughs" turn out to be something serious, if the person in question is being regularly exposed to two or more sources of respiratory toxins. No one- not even a lung specialist- can tell you with any certainty that smoking is worse for you than working a coal forge. People are far too individual to make a blanket statement like that. It depends on how much of what you have been exposed to in the past, and how your lungs reacted to it. But if YOU notice that you cough more when using the forge than when smoking, or that you cough more when smoking than when using the forge, that might be an indicator... I think you should wear a p-100 respirator when working a coal forge- it will remove all of the particulates that are larger than .03 microns. Take care of your lungs so you can keep forging!

I haven't tried this, so I don't know if it works, but there's information on the web about putting a grinder to a piece of metal and telling what sort of metal it is by the color, length, and "branching" of the sparks. Another option would be to ask one of the metallurgists on this or another forum what type(s) of steel were commonly used for that kind of saw blade. For drill bits you could try Harbor Freight's cobalt bits, which are surprisingly cheap and work quite well. I'd use a drill press at slow speed, and maybe a bit of oil to keep the hole cool. Good luck!

Hi Greenbuggy, I'm a beginner in terms of making forges and burners, and this is really just me thinking out loud, but here's what I remember reading about fluid dynamics, the ASHRAE books, experiments done at MIT, and a few other sources, and some stuff I've been thinking about: 1. A smoothly-rounded entryway means more fluid can get in more easily, as opposed to an entry with sharp edges. Even smooth sharp edges will allow much less fluid to get in, than a smooth, rounded entry. A half-toroid shaped air or gas inlet will allow the most fluid in with the least friction. 2. Wind tunnel photos show that a surface with a "golf ball" texture creates lots of tiny little vortexes and the main flow of gas or air can then "slide" over those vortexes with significantly less friction than you would get with a smooth or even a polished tube. Which is why they put all those dimples in golf balls. Whale flippers have bumps on them that increase the flippers' ability to move water, so I guess that means that "innies" decrease resistance to flow, and "outies" increase the ability to more easily move larger quantities of fluid? (I haven't fully wrapped my head around this one yet...) 3. A longer tube gives a flow of air or gas more time to "settle in" and become smooth. A short tube actually takes more energy to move the same amount of fluid. There's a formula that involves the diameter and length of the tube, the amount of fluid moving through it, the viscosity of the fluid, and the speed of the flow. 4. If you have to have a 90 degree elbow in a pipe used for fluid transfer, the wider, and smoother the bend is, the more fluid that will get around the bend easier; the turbulence caused by a sharp 90 degree elbow, on the other hand, can decrease the volume of flow through the tube/pipe by 40%. So, sharp bends in the tube would mix the air with the propane. 5. I think- not sure, but think- that if you have gas and air going through a pipe and you want them better mixed, you can run the pipe into a significantly larger-diameter pipe, which will cause more turbulence and space for the mixing of the two. One factor to consider, though, is that propane is heavier than air. 6. A toroid-shaped air outlet allows more fluid out of the pipe, given the same input pressure and volume. I think that a toroid on the end of the burner tube would make for a shorter, fatter flame, but not sure. I know the shape of the outlet on a fan or blower has a lot to do with how the air moves out of it, so it would have to affect how a flame moves out of it, too. 7. I've been wondering about shaping the inside of the burner tube like a car's muffler. Mufflers use interior baffles to break up the flow of fluid, and I'm thinking that baffles would also therefore mix up the gases in a burner tube. 8. I think that Corin's burner draws in the primary air through the back end of the burner tube, and put in the gas from the side. This would make sense because the ideal mixture for propane and air is over 90% air to under 10% propane, so you want to make it as easy as possible for lots of air to get into the tube. It would be easy to put a toroid shape on such an air inlet, and also easy to angle the gas inlets so they shoot the propane into the pipe to induce a spiral mixing flow as you were talking about. But I don't know how to choke off the primary air flow to adjust the flame... But like I said, I haven't even built a forge yet. I have most of the materials, and am going to start on it in a few days. I'd like to hear how yours works. David

I use the rat poison that has a blood thinner in it, and occasionally I find mumified mouse and rat carcases under workbenches and behind things. A few times there has been a stink that takes a few days to go away, which is from them dying inside the walls. Also, flypaper put around the perimeter of the walls inside the shop- the little critters step a foot on it, can't pull it off, so they put another foot on it for leverage. You find them scuttering around the next day, with the flypaper attached to their feet. And of course cats work, but they need to be in the shop late at night after you've finished working, because generally the mice and rats come out at night when it's quiet.

Punch it carefully and exactly where you want the hole, clamp it solidly so it's nestled between two V-shaped objects, then very slowly with a sharp drill bit start drilling a small pilot hole, then it'll be easy to drill the larger hole.

I decided on fully-refined canola oil, because it has a very high flash point, and five gallons of it cost about $17 at one of those stores where the restaurant owners shop. It's worked very well for quenching 01 steel knives and chisels, but I haven't tried it yet on any other kinds of steel. Also, I wanted canola because I'm going to make some kitchen knives and I'm concerned about quenching in toxic oils such as the petrochemical or other ones.

You might want to call the manufacturer and talk with their techs about your intended use. The suggestions the other guys have given you are some of the same information I got from the Extech techs, about problems from the range of accuracy, and calibration which is expensive. I ended up getting a digital thermometer with K probe, from Grainger. I think it was about $200. It's the cheapest one I could find that goes up to around 2600F. One other option is learning to read the colors, which admittedly can be tricky, but if you are using a steel that gets non-magnetic at its austenitic temperature, which I think most do, the combination of color and non-magnetic could do it. Kevin Cashen talks about how important it is to soak the metal at temperature for long enough. He said he soaked some 01 steel at something like 1550 degrees farenheit for hours, and then took photomicrographs of it, and the grain structure wasn't damaged at all because the steel never got hot enough to start decarburizing or growing big grains. Another master bladesmith told me that it's common for people to not soak metal long enough. David

Hi Mike, here's Ed Fowler's phone number: ***-***-**** I got it off his web site and called him a few days ago to ask a question about 01 tool steel. He said he likes 52100, and talked with me about how to heat treat it but I don't remember what he said. Give him a call, he'll explain it. Lots of experts say he's the go-to guy for 52100, that he invented a new, more effective way to heat treat it. I used a jig saw to cut some deer hook knives out of hardened 52100, and I'll tell you what: you want that stuff annealed before you cut it! David Phone number removed, due to permission lacking from owner

I don't know about quenching other kinds and shapes of steel, but for quenching knife blades it's my understanding that you want to use a very straight slicing motion, knife-edge-first or dipping the blade tip-first, pulling it out and then dipping it again. And you do not want to figure eight or any other motion would cause problems with one part of the metal cooling quicker than the other parts as the S-wave of austenite turning into martensite goes through the steel faster on one part than another. What you want in the quench is as smooth an S-wave as possible going through the metal. The problems could include things like the blade cracking visibly during the quench or the first time you use it. I used a figure-eight motion while quenching a chisel and the first time I used it, the entire tip fell off.

I quenched one of my chisels in a paper cup full of olive oil. That made me nervous enough that I got a steel popcorn container which seems a bit safer...

You know you're a farrier if your wife wakes up one morning, looks at her feet, and says, "You been sleep-walkin' again, ain't you?"

Every time you go to a restaurant you go into the kitchen and tell the chef he needs a real knife. Even McDonalds... Your idea of fun is posting a video of you shaving with your lawnmower blade after you spheroidize, regrind, heat-treat, and sharpen it. Your 105 year old mother in law tells you that the 50 hunting knives you have already made for her are probably enough, and maybe you could just get her some flowers for her next birthday... You always carry a skinning knife with you in your truck, because it's the perfect bribe for getting out of traffic tickets. You don't own a table saw because "A real man can make cabinets with a sheet of plywood and a sharp paring knife." When a boy wants to date your daughter, you take him out to your forge and have him make a 15" bowie knife out of 01 steel, and then you send him off into the woods, telling him, "Come back with a bear skin, or date someone else's daughter."