Latticino

Looks like you are on the road to making some very fine tools. Have you used them as yet (best test for functional tools)? Is the axe mild steel with a high carbon bit forge welded, or mono steel (and if so what kind)? Up to you, of course, but personally I like to see the axe cheeks drawn down a bit. Of course you will need a cheek plate to finalize your eye in that case. Might consider using a different drift for the axe rather than the same flattened oval you used for the hammer eye. I've certainly done the same, but these days prefer a thinner, wider eye for an axe head (more like a commercial axe eye). Just my personal aesthetics, these look very functional as is.

For the other point of view, I like classes, but for me it is my favorite form of vacation. I'd rather spend a week in a class, sweating away and learning new smithing techniques, than the same week in Vegas, lying on a beach somewhere, or off on a cruise. Each to their own, of course, and a lot depends on your finances. Joining a local group is typically a lot cheaper, and you can set yourself up to forge at home for a nominal investment. Just remember that the experienced smiths in your local group are not being paid to instruct you, and though they are usually very generous with their time and advise, a good show of respect, enthusiasm and careful attention (not to mention a periodic box of doughnuts) will go a long way.

I am hardly an expert in pattern welding, but the procedure I listed is one of the ones that is successfully used for exposing pattern welding "texture" on knives that are layered with high carbon and nickel steels (i.e. 1084 and 15N20). It may be for Cable Damascus you can get away with just an acid soak as Iron Poet indicates, but I would at least finish the surface to get rid of the scratches. Those will certainly reduce the effect of the pattern.

Might consider grinding blade section, at least, to a finer polish, oil hardening, tempering, then finish polish and light 30% ferric chloride etch. You probably have a very nice pattern weld hiding there. You did all the forge welding work, why not show it?

I'm with Thomas on surfing the unread content. Works great for me, and I love this site and all the great info I've gleaned from frequenting it. Only issue I have with the format is the irritation of having to refresh the page every time I try to follow a thread onto the following page (i.e. going from page 1 of 2 onto 2 of 2). This is minor, and most likely related to my using Windows Internet Explorer on a Windows 7 machine, but don't have that issue with other forums I frequent. Note that one of the other "good ones" is Bladesmith'sforum.com and it has an apparent similar structure to this one. I've also participated in some Facebook blacksmithing sites but found them extremely poorly structured, impossible to search adequately and full of misinformation, some dangerous. Might be my inexperience with Facebook though. Many thanks to the moderators and owner for setting up and maintaining such an excellent site.

@John, wish we had a like button for that comment. Going to have to remember that one

Casting aluminum and silicon bronze is one thing. Casting steel something else altogether. Please do more research, outside of youtube, and try to avoid a Darwin Award. I have no experience with foundries so can be of no real assistance, but do know the temperatures and atmosphere control involved are very different.

Why use hose and quick connects at all? Hard pipe right up to your burner connection with 1" schedule 40. If you need to be able to move it put in an isolation valve (full port) and downstream union. Make the final size reduction inside the burner body where you can adjust the orifice size iteratively to match your blower output to the maximum pressure you develop with the gas. Since you are developing your own burner design you had better expect to do some testing and optimization. With low pressure gas supply, my policy is to get as much into the forge area as possible. Can always turn it down, but if you don't have enough you are out of luck. Residential pressure natural gas forges definitely can work, as I have built several at this point. I am still struggling with getting my multiport burner to work up to my standards, but have successfully forged and even forge welded in the existing unit.

I am not aware of any design guidelines for the mixing tube configuration for forced air burners. I believe that there are too many variables for potential configuration to set them, but in my mind the only drawbacks for a mixing tube that is too long is the potential to "stall out" your low pressure gas entry by requiring too much static pressure to overcome the friction of the mixing tube and the backpressure of the burner outlet. I use commercial burner components currently, Inadequate precombustion mixing is not the issue. The issue is the potential for combustion in your mixing chamber. Believe me you will know if that is occurring. It will be loud and quite scary. The mixing tube will also get hot. Manifolds can be difficult to balance. Typically some sort of valving is needed to properly balance the multiple outlets. I prefer to minimize any potential leaks after the air and gas have been mixed (like valves with packing). Initially I would stick with a single burner if possible. I have no information on flame speed other than you need to strive for a stable flame. The stable flame should be burning just at the burner entrance to your forge, and not either lifting into the forge or burning back into the mixing chamber. I am not planning on performing the calculations to validate the proposed equivalence between the orifice and long tube run. It is certainly possible that there is one, but you will need to do some rather tricky calculations to confirm it (Reynolds numbers and the like). My residential pressure forge uses a 1" hard piped NG line, for what that is worth, but the line runs at 1.5" underground for some 100' to the main gas house regulator..

Check out some of Tom Latinè forged tools for great examples. I say why shouldn't I want my tools to be a work of art, or at least fine craft? They are the things I use when I'm trying to be at my best. Make them myself or celebrate others skill in making them, both are valid, I think

I thought they might be misusing the term, indicating it was a technique rather than the result of a series of operations (like a temper line for instance). Tough to achieve that level of presentation in the time permitted, particularly since a lot of it is traditionally influenced by the laborious hand polishing step. Your choice of the clay heat treatment makes even more sense. Thanks for the clarification. One other question, if you don't mind. I heard from the rumor mill that the producers of the show ask contestants to sign a contract that requires them to fork over a percentage of their future knife sales in return for the exposure they get from the program. Can you corroborate this?

Agree that Theo made some very good design choices for his chopper. The shape clearly fit the test format, and the choice of full tang worked well for both strength and speed of handle assembly. Though it gave him some trouble down the road, I also think that he was particularly clever in claying the spine of his blade, though not necessarily to create any kind of hamon. If you consider the mode of failure for Walt's blade you will understand why I feel that way. I certainly agree with you Frosty as regards the San Mai blade. I sat there the whole time marveling out loud why that experienced bladesmith didn't go for the folding operation to get his "dog in a blanket" construction. Guess when you get into a rut under pressure it can be hard to see the forest for the trees (to mix metaphors....). The one blade making technique that I wasn't completely familiar with was the last one (canister Damascus, straight Damascus, San Mai, and <some Japanese term I can't remember to look up>). Can anyone help clarify this for me?

Great job Theo. I was also quite disappointed that you didn't get to show us the whole 3-D printing and casting process, or at least part of it. Sure would have been a shoe-in for the directive to show something that only you could do in your own shop. I was really hoping for one of your cool "twisted wire" printouts for a guard on that Naginata, or at least a butt cap for the wood section. Too bad you couldn't use a program you already wrote and just churn something out. I know that there is a lot of upfront programming required for 3 D printing, but couldn't you just adapt something you already had made up? After all the 3D stuff is just another tool. I'm sure they don't force the other contestants to make new press or power hammer dies, fullering tools or the like in the time allowed.

By all means test it out if you have the inclination. Nothing is better than an empirical test for proving a concept. Not sure of where you are getting your BTUH data from for burner operation, but assuming your calculations are correct I believe that you may have the following issues with the proposed design: Typically I select burner blowers for high pressure/low airflow operation as the standard commercial ventauri mixers have some backpressure at the mixing chamber. With a simpler mixer (straight tube gas side inlet) you will likely have less loss in the mixing chamber, but there will still be wall friction and burner outlet friction. I believe that the computer pancake fans are optimized for high flowrate and low static pressure. Though I don't have a fan curve for them I wouldn't be at all surprised to learn that at full airflow they only exert 0.1" WG of external static. The key reason for getting a fan curve is to see whether the fan will give enough static at the proposed reduced airflow, or just stall out. 5 CFM in a 1/2" OD mixing chamber has the fluid velocity at around 3,667 ft./min at standard conditions. This equates to a duct friction loss of 97" WG in each equivalent 100' of duct. While I know you don't anticipate a long duct length (by this calculation 3' of the 1/2" pipe would be 3" of static loss, so I think you may have missed an order of magnitude somewhere) you need to be aware that any elbows or rapid changes of duct diameter will equate to a fairly significant equivalent length (as will the entry condition for the fan and exit condition for the burner). A single 90 degree elbow can be more than 15' of equivalent length. For this example that is almost 14" WG for an elbow alone. Note that a 1" mixing chamber is much better (2.7 "WG for each 100'), but that is still relying on your estimate of 30 MBH burner output. Placing computer fans in series (your turbine configuration) will theoretically maintain the flowrate while increasing the external static pressure available. In practice turbulent effects and fan speed controls makes putting fans in series rather problematic. My suggestion would be to pipe up your forced air burner in 1" pipe, right up to the forge inlet. At the end of the mixing chamber I would recommend some kind of a burner outlet (multi port burner block, flame retention ring, 1 x 3/4" reducer...) to provide a clear velocity transition at the burner exit to allow you to tune burner operation easily while limiting precombustion in the mixing chamber. You certainly can try a pancake fan, but keep that centrifugal draft inducer fan around if it doesn't work (I assume it is a centrifugal fan you are talking about, not one of those cheap, inline paddle wheel draft inducers that get put onto furnace flues). Good luck and please post your results. Remember your residential pressure natural gas line is typically quite low pressure (0.25 psi), so long runs of natural gas will have to be larger diameter than your relatively high pressure propane. By the way, yes I have made a couple of 3/4" mixing chamber blown burners (for glass furnace pilots), but those used industrial ventauri mixers and air provided by the same large high pressure blower that I was using for my main furnace burner. Kind of a different application. May try to pipe one up for a paint-can forge sometime, but will likely use a small Dayton squirrel cage blower.

Take a basic bladesmithing class.

Can you explain why your door opening is taller than the opening of your forge? Normally I make them shorter to aid in keeping the heat in.

Very cool. Please say hi to Dick for me.

These inline fans appear to be optimized for high volume and low pressure. I could not source a fan curve, so can't be sure. There website does indicate that the 6" fan provides 440 CFM at a required energy input of 121 watts. Using standard fan calculations this gives us approximately 1.8 " WG of external static at that flowrate at standard conditions. Also not sure what airflow needed for your coal forge configuration, but think it more likely that you will need relatively high pressure and low flow. Blacksmith Depot sells one at 112 CFM flowrate at 2.55 " WG external static pressure for smaller forges, so I'll assume that is a good general size (substitute electrical current for the flowrate in CFM, and circuit voltage for the static pressure as a good parallel for analysis). Depending on your duct configuration you can use up a lot of the external static pressure capacity of the blower in fittings as well as entry and exit conditions. Without a fan curve it is hard to tell what static the fan will provide at the lower flowrates you may want for your installation. Worth trying, I guess, but try to minimize your duct length, offsets and sharp transitions.

Going cheap on a motor for a belt grinder is a false economy in my opinion. If you don't get one rated as TEFC you are either going to have to build a filter box to keep the metal grindings out or replace your motor after the dust gets into the windings. If you don't get at least a 3 speed pulley setup you will be letting yourself in for burned blades and ruined temper after heat treat (unless you plan on hand sanding after heat treat of course). I have 1.5 HP on mine and can still stall it at times (but that may be a product of my VFD torque limiter and/or belt drive), so would recommend at least 1.5 HP. You also need to decide whether you go with a 1750 RPM or 3600 RPM motor, which is directly related your drive system.

I certainly don't qualify as a truly skilled knife maker, but I'll take a stab at tending the same kind of constructive criticism that I appreciate for my own work. All of this is purely subjective as regards my personal aesthetics, your blade appears quite balanced and useful, so it passes the critical "function" test as far as I'm concerned. I also like many of the design choices, including selection of handle scale material, location and size of rivets, and general proportions of blade and handle. As far as things I'd look into further: It looks like your primary bevel is too short, or your secondary bevel is too long (hard to tell from the photo). I personally strive (not always successfully) for a crisp break between the primary bevel and the flat section of the blade. I also like to see the primary bevel either follow the contours of the blade profile, or clearly depart from same. To me it appears that you have tried to follow the profile, but not succeeded, especially near the tip. I also like to see a defined plunge line where the primary bevel starts at the riccasso as well as a clearly defined riccasso. Suggest you try to photograph with diffuse natural light to minimize the washing out effect of the camera flash. As I noted a nice looking early effort. Of course some of knife evaluation is in the intangibles: how does it feel in the hand, is the balance optimized for slicing or chopping, how successful was the heat treatment... Bottom line is that you are happy with it, and you learned something from making it. My aesthetic suggestions are only recommendations for your next project.

Can always make a bigger base plate and just adjust height of the vise. Current setting appears to allow vise to lower, but not raise up, so larger base plate will work. However I do prefer to have the post tied to something solid as well to prevent it walking under load.

There was a post not too long ago on propane fired NA micro-burners. I would expect that one of those would suit, but will still not give you the output of oxy-propane or oxy acetylene. You could also look into an acetylene torch sometimes used by jewelers and plumbers. I believe it is called a presto-lite, and they are often available cheap, on the used market (Craig's list and the like). Not sure on the output, but think they are used for brazing on a regular basis, so they will most likely be better than a big-box butane torch.

Hard brick will have lots of thermal mass and limited insulating value. It can be used for a forge design, but will be quite wasteful as regards energy. My preference is for a relatively thin inner layer of refractory or hard brick and a thick outer layer of insulating material (soft firebrick or refractory blanket). The Zoeller brick forge is made of soft (insulating) brick. If you are going to follow it I would use soft brick rated for 2600 deg. F as is clearly spelled out in the design sheet.

I think that you will find that the typical wisdom these days is that brake drums are a bit too deep to be effective while brake disks are a bit better. Of couse a lot depends on whether you are planning on burning coal or charcoal.

Nice blade, but gorgeous handle.