Latticino

I purchased one of those from Amazon as well. Around $60, if I recall correctly. Seems fairly accurate based on comparisons with thermocouples in a heat treat oven, but have read other postings from "authorities" that indicated there can be fairly large discrepancies based on the size of the cone and emissivity (note that the one he is commenting on is only rated to 1,500 deg. F, not the same as the one John and I have): This from Jerrod Miller (a metallurgist): I have yet to find one I trust for what I would call a reasonable amount of money. Two big things that a lot of people do not realize with IR thermometers is the size of the cone for the reader (close to the gun reads a small area, farther away a bigger area) and emissivity constants (a material dependent value). When we get to the temperatures we care about in smithing, emissivity constants become important and you will need to calibrate and adjust it for the material. The cone for the one you linked has a 12:1 ratio, so at 12 inches your diameter being measured is 1 inch. So unless you can be sure to be measuring just your steel, you will get contaminated readings (measuring the forge wall with the wrong emissivity constant for it).

The limitations on your burner operation are also related to a number of factors, so it isn't a simple answer. The forge interior temperature directly influences the flame front speed (the velocity of the flame burning back towards the fuel/air source at the outlet of the burner). You want this flame to be stable, and located right at the outlet of the burner. As I've noted on numerous occasions, it is a balance between the velocity of the air/gas mix at the outlet (set by the volumetric flowrate) and the flame front speed. If it is too far off, it can easily "flame out" and, hopefully reignite (forge will appear to be "huffing". If too far into the burner outlet you can get preiginition in the mixing chamber (anything from "popping" to small explosions). Burner outlet area may need to be adjusted to achieve a "sweet spot" (though there are also burner outlet designs that work at a wider range - flame retention outlets and multiport outlets). As is pretty logical, a larger outlet will support more fuel/gas mixture at a lower flow speed, typically leading to a more "powerful" burner, but one that may not be able to be turned down as far without burning back into the mixer. You also have to be careful, again for flame front speed reasons, when turning down your forge from high to low fire. My recommendation is always to turn off the gas and just run on the blower until the forge drops to the desired temperature to avoid having the flame burning back faster than the lower air/fuel mixture can support. Overall length of flame can also be a factor (as Thomas stated), with how long the dwell time is inside the forge. Longer dwell leads to more energy transfer. Choice between oxidizing and reducing flames have been well described by Buzzkill. There are also characteristic forge interior sizes that work better with different flame configurations (both forge interior volume - for proper combustion, and forge width opposite the burner outlet - for properly developed flame length). I expect the 1" burner may be too large for your 250 cubic inch forge, but that is hard to tell without experimentation. You can always choke it down to a 3/4" outlet with a reducer to see. Best and most efficient path to increasing forge temperature IMHO is to ensure you have good operable doors. This is easier with a blown burner, so you are already on the road to success. Good luck.

There are a couple of different ways to reduce the airflow from a blower. If the motor is capable of speed control you can reduce the RPM. On most blowers, but not all, you can "ride the fan curve" by increasing the resistance on the blower outlet with a valve or slide gate of some sort (some can go unstable at elevated external pressure). On some blowers you can reduce the airflow by restricting the inlet (but this can be a problem for others, overheating the motor). You can also add a waste gate that directs some of the air elsewhere (possibly to a slot diffuser at the opening of you forge to direct the dragons breath upwards). Lots of options, but first you have to ask yourself: How do I know I have too much air? How much fuel/air mixture is needed to burn to maintain a stable flame at the forge temperature I need for the forge I built (changes at different interior temperatures)? Should I reconfigure the burner outlet before reducing airflow?

Absolutely on the crab cakes. Sorry for the situation, but 15 years is a great run. Good times on both sides I'm sure.

Unfortunately I can't watch your video at work, but will try to check it out later. The typical "rule of thumb" for hood capture velocities is around 100 ft/min, so assuming you have a hood on the order of 2' x 4' your current 1,530 CFM should be more than adequate (if it is actually operating at that flowrate). The 10" nominal duct size at that airflow will result in a duct friction loss of around 1.2" WG/100' of duct (1.2 inches of water gauge head loss every 100' of duct). This doesn't seem like much until you realize that a duct elbow is an equivalent 15' of duct and the abrupt transition from the hood to duct is equivalent to around 35'. It can start to impact on your fan selection (fan curve vs system curve), but not knowing the specifics of your fan I can't theorize on what you actually have going. My guess is that you are riding the fan curve down and actually the fan capacity is 1,530 CFM at essentially no static pressure loss, and likely a lot less at the current flowrate. Since you may only need around 800 CFM of exhaust, it is likely not an issue. In fact at 1,530 CFM I would have selected a 16" duct for both static loss and air noise. Depending on the specific fan selection, it may only develop 1 or 2 inches of static before stalling, so likely you are balancing out at significantly less exhaust flow than you think. As I indicated, this may be fine, as long as the cooling effect is working for you. I'm not a big supporter of having the fan motor being in the airstream for a hot fume exhaust system. I look forward to seeing your solution for this. A belt drive system with the motor out of the stack is typically preferable, but you may be capturing enough shop air to keep it running acceptably. Just make sure you have an adequate makeup air opening to the outdoors to supplant the fan. I really like your 4-bar forge door, fan powered burner with PID controller and powered rolling mill. The dies on the bottom shelf look to be for a press as well, so I expect you have a very efficient shop. It is certainly a lot cleaner and better organized than mine...

Well said John.

Frosty, I'm afraid that you have come to my limit in fan/blower design terminology. I've heard of overloading and non-overloading fans (which basically has to do with fan system effects on the driving motor), but I've never heard or seen the terms positive vs free flow, or transparent vs. opaque used in the HVAC field as a description for fans or blowers, and I've been in this on and off since the early 80's. Doesn't mean it isn't common for specific trade applications (automotive for example), or something that a blower designer might be aware of. Some good bullet points regarding fan design in this ASHRAE PowerPoint presentation: https://rockymtnashrae.com/downloads/2012_Tech_Conference/introduction_to_fans___ashrae_4_20_12.pdf

O-1 is the canonical oil hardening steel, and has been in use for a relatively long time. Please note that heat treatment "recipes" used for knife crossections are likely not appropriate for a 1" shaft used in a mower. For this kind of application you should be using industrial grade heat treatment services and quality tempering as the last thing you want is a brittle steel part rotating at high RPM. I'm not sure why you chose O-1 in the first place. I would expect a mower shaft would need more toughness than hardness. I would be selecting needle bearings with an inner ring (or race) that is appropriately high chromium to limit corrosion (see below) and most likely use 1045 or 4140 shaft stock (that is water hardening) for toughness. Honestly, even if the needle bearings were directly resting on the shaft, I would still probably go with 4140 or similar (though I would expect a machined and appropriately polished race would greatly increase the lifespan of the bearings and shaft). Note there is a great, free, downloadable heat treatment app (Heat Treater's Guide Companion) that is sponsored by the Heat Treatment Society under the ASM International Umbrella. They recommend austentizing O-1 between 1455 and 1500 deg F prior to oil quenching for 63-65 HRC, then tempering between 345 and 500 deg. F for hardness ranges between 62 and 57 HRC on a sliding scale. To answer your direct questions: Double heat treatment is typically bad, particularly if you don't control grain growth or have an accurate way to measure stock temperatures. File hardness depends on the file being used to check the surface and the experience of the tester(and can be confused by the potential for surface decarbonization). Also, "annealing" is to soften the stock so it can be machined. This differs from tempering to remove brittleness after the hardening quench. I would be very wary about using the shaft you have made.

Mikey, More often than not these will be axial fans (at least if you mean the ones shown in the first picture below). Whether they are called tube axial or box axial appears to be a matter of length of the casing. Some manufacturers will call these mixed flow fans due to the geometry of the impeller, but essentially they will fall under the general umbrella of axial fans IMHO. By the way, as I understand it the word "impeller" refers to the function of a fan or blower blade, not it's configuration (used to move, or "impel" the fluid from one location to another. Note this same designation is used for the "business" part of most pumps)... While families of fans do tend to have common defining characteristics, the real key to proper fan selection is to review a fan curve and chose one that properly matches your distribution system (system operating point intersecting with a stable, efficient and quiet (if possible) point on the fan curve. Also note that some computer elements are cooled with centrifugal fans, which can be subcategorized as forward curved, backward curved, airfoil...

Frosty, Well I've been in the business for a little while and have heard of a lot of different kinds of blower: centrifugal, forward inclined, backward inclined, radial, vane axial, mixed flow, plenum, squirrel cage, sidewall, high pressure/low flow, low flow/high pressure, high plume lab exhaust... but I've never heard of transparent and opaque blowers. Did you coin those terms? Do they have a reference for a particular application (like bilge blowers being used to exhaust out boat enclosures)? As I've mentioned before blowers or fans need both a airflow and external static pressure rating at a number of conditions to establish a fan curve. In my experience, for "gun" burners, the better choice is one that is relatively high pressure and low flow (typically, in the hobbist world, a centrifugal fan with an radial impeller) Some examples from the fabulous interweb...

Nice looking vise, and one of the often overlooked key tools for setting up a good blacksmith shop. Prices vary a lot with location. In my area that would be on the higher side for a vise with 4' wide jaws, but just about right for one with either 5 or 6" wide jaws (that is width of jaw, not jaw opening size). Screw threads and jaws look to be in excellent condition and all the parts are there, so you are ahead on that account. Hope you can get into the class, sounds like fun. From all I've heard the Northwest Blacksmith Association is a pretty active group, so it is certainly worth getting involved with them.

Yes, most likely your old files were worth more as stock than scrap. It is pretty easy to test whether a particular file is easily hardenable, and your smithing friend should know how to do that.

I wouldn't worry about pressure, the key is keeping a good flame profile in high and low fire. As I've said in the past, while ribbon burners have many advantages, one key disadvantage is that you need to be careful in turning down the burner to a low fire condition after your forge has been running at high fire long enough to get very hot. Note, I started with a blower that size for my forced air natural gas forge and switched to a larger one to get more BTU output. Your forge shouldn't "choke" due to too much fuel, you should see a lot more dragons breath reduction flame at the forge doors where the gas fuel mix is hunting for more air to burn. If your flame is not heavily reducing, but just lifting off the burner face, it is a function of the burner outlet port size as related to forge interior temperature (and consequent flame front speed).

Very good name hammer. Quite large size as well. Looks to need some significant work for reassembly, but likely quite promising if all the parts are there and the pistons haven't seized from that rust. Good luck with it, careful rigging it home if you get it, that's no light weight either.

Excellent advice from George. Don't overlook shared rental of industrial space either. Not all of those old large factories got renovated into condos, some got partitioned up and have light industrial tenants. My first, and best, shop was in an industrial building with fine woodworkers, a filter manufacturing company, toymaker, and two other glassblowers, among others. It was nice to have metered natural gas, a freight elevator, periodic loan of an electric forklift, 3 phase power.. They are out there as well.

Afraid you are going to find that most reputable storage facilities will not allow you to have any sort of open flame inside their units, so you might consider how you can creatively setup somewhere else. Good luck.

Had my dog triumphantly bring a small possum up to the back door of the house with it hanging loosely in her mouth. Needless to say my wife totally freaked out. I went over and told the dog to drop it (the only reliable command I taught her - as a "pittbullish" mix a critical one). She dropped it, and it picked itself up, shook a bit and ran off into the night. Got a look of disappointment from my dog, but at least she got a biscuit.

I find in a coal forge I tend to get more clinker when I have the fire turned way up for forge welding. If you are just doing basic forgings right now you might want to consider running your fire a little cooler. Do you religiously turn down the blower to minimum every time you take the stock out of the forge?

Thanks for the feedback everyone. I went with a "complicated" handle with high end materials to try to balance the simplicity of the blade.

First try at a wa style handle. I know this is a bit of a mixed bag, with a Japanese style handle on a European chef's knife, but I wanted to try this kind of handle, and didn't have time to forge and finish a new blade before the deadline (wedding gift). I think it is a bit blocky, though it does fit my large hands quite well. Next one will have different proportions I think. Blade was forged from 1 1/2" x 1/4" 1084 and is now under 1/8" thick, 2 1/2" wide and 9" long. I also tried the "no-plunge" grind blending for the first time as well. It is a lot harder than it looks.

There are innumerable different configurations and sizes for Kukhri. My recommendation is to find one you like the image of online then sketch it to the scale you want it to be that fits your blade stock (if you are going purely stock removal). These are typically pretty thick as they are "choppers" not "slicers". Google "Himalayan Imports" for a decent crossection of what is available. If sketching it is too much work for you I'm not sure that you should take up making it in steel. As a starting point you could look at this drawing of the classic British Army issue version:

The yatagans I have seen online and in museums look very little like what you have in your photos (more like the below). They are long, slender with a slightly swept down point and slight belly. As far as I know these Turkish/Ottoman blades are available in a variety of lengths, from long knife up to medium size sword, and typically have a distinctive handle that includes pronounced "ears". Very little like the photos you have. Perhaps you want a different type of blade. I think your translator program may have failed a little and you are asking if a "vehicle leaf spring" can be used for blade stock. The answer is yes, with a caveat: it is best if you source unused leaf springs, which can sometimes be found from repair spring shops. As you may know the forging of a blade is only a very small part of the process, with knifemaking requiring an understanding of metallurgy, grinding/stock removal, heat treatment... If this is your first blade, I would recommend something easier and shorter. A yatagan is a fairly advanced form IMHO.

And now it is mine! I can say that it is even nicer in person than the photo.

John, That is fascinating. Thanks for sharing.

At this point I would use it till it does. I know that for how hard I use my post vise I'd likely bend a 1/2" square leg, but is kind of hard to tell from your photo what the proportions are. Just use it till it doesn't work the way you want it too, and fix it afterwards.