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Dan Hertzson

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  1. Dan Hertzson

    Anvil weight question.

    Recommend considering some cold chisel work
  2. Dan Hertzson

    Anvil weight question.

    Makes it easier to lug on and off the pickup truck for the anvil shoot...
  3. Dan Hertzson

    How useful are recurve designs?

    As with any tool, there are different configurations optimized for different uses. I would never try to replace a chef's knife made for cutting on a flat board with a recurve blade, but a slight recurve certainly appears to have some advantage in cutting free hanging items. I believe this is a combination of the increase in cutting edge length per relevant length of blade as well as the geometry of the edge to object to be cut orientation during a swing/slice cutting operation. Cutting involves both dragging the sharp edge across the object to be cut (slicing) as well as providing a force vector down on the object (chopping and progressing the slicing cut). For some cutting activities a recurve seems to coordinate well with the ergonomics of knife use to make the cutting more efficient.
  4. Dan Hertzson

    Fetter Lane Sword No2

    Fit for a king...
  5. Dan Hertzson

    symetrical axe wrap

    I'd have to check my notes, but it looks like you are starting with plenty of mild steel. I assume that you plan on forge welding in a high carbon bit? Barring following James Austins asymmetrical wrap design for bearded axes (which works very well, if you follow his steps carefully. I don't know where youa regetting the "too thin" comment)... As regards forging sequence, the one that I have learned from a variety of sources that has worked for me is as follows: fuller back side of stock in two places to about a 1/2 thickness for a 3/4" to 1" poll Fuller the front side of the stock in two places for the front of the eye (recognizing that as you thin the cheeks the sides of the eye will grow, a good use for your clay model) Some folks spread the bit side of the axe preform a bit before wrapping, which can help if you don't have a power hammer, press or striker, but I think this over-complicates things. However for a long beard, like in your design, it may have you fighting with upsetting the billet less if you can keep the sides symmetrical and upset the front a bit before welding. Clean surfaces to be welded, wrap and forge weld the sides of the "butterfly" together, paying close attention to the joint at the front of the eye (you can either put the HC bit in prior to welding the bit side or leave it unwelded and open it up for a final weld for the bit. My preference is to scarf the two front edges after the front of the eye is welded so you can do that simultaneously, then split open if necessary for the bit with a chisel with the blank held carefully in a post vise to avoid having the split run further, but I've done it both ways). Forge to spread and upset the beard as required
  6. Dan Hertzson

    This is why I'm always recommending files to people

    Wonderful detail on construction of the bowl. Given me a lot of good ideas. Look forward to seeing this one finished and (hopefully) etched to show all that lovely wrought iron. Thanks!
  7. Dan Hertzson

    This is why I'm always recommending files to people

    Lovely job draw filing and finishing. I'm particularly impressed with the area around the eye and double chevron ornament you added there. Just finished a pipe hawk class with Jay Close and we were instructed to change directions for our filing in this area (perpendicular to the longitudinal filing done on the blade). I'm guessing you did you final passes hand sanding in the same direction as the blade for consistency? Also you mentioned peripherally that you turned the bowl on a lathe. It looks as though you made the body of the hawk using a wrap and weld method. When we did our hawks with that kind of post connection to the bowl we went with integral construction (all parts made from a single piece of 1x1 mild steel with a HC bit welded in). If you don't mind sharing secrets, how do you form your bowl on the lathe and how are you attaching the strap to the rest of the hawk (silver solder or brazing)?
  8. Dan Hertzson

    TW-90 motor

    Thanks so much for taking the time to check. I am reassured.
  9. Dan Hertzson

    TW-90 motor

    Strange question I admit, but I recently purchased a used TW-90 and am curious whether the original owner swapped out the motor. I believe that Travis uses both Leeson and Baldor motors, but am curious about the motor RPM. Mine runs very smoothly, but the motor is a 1750 RPM 2 HP motor. If anyone out there who has one of Travis's machines and is willing to check the RPM on the nameplate and get back to me I'd certainly appreciate it. Thanks Dan
  10. Dan Hertzson

    Quenchant amount q?

    Suggestions: Vertical quench: piece of 4 or 6" capped sch 40 PVC pipe Horizontal quench: aluminum turkey basting pan. Full blade quenches for either with oven snap temper then tempering tongs or torch to draw back spine if absolutely required.
  11. Dan Hertzson

    Bone handles

    From my limited experience with bone and antler I would strongly suggest you avoid exposing the pith/marrow, or even getting too close to it. It is very friable, and unless you plan on stabilizing it with a resin it will likely not hold up well.
  12. Dan Hertzson

    Hot fitting a wrought iron guard

    I'm considering hot fitting a wrought iron guard onto a hidden tang Bowie that I forged, ground and heat treated recently. This will be the first trial at hot fitting a guard on a knife (did it once on a sword in a class), but I wanted to try it this time because when I punched the guard while forging it I got a nice "dimple" on the blade side that I'd like to keep rather than grinding that surface flush. What I'm trying to figure out is how close to the ricasso I should file the slot before hot fitting. The taper angle on the tang is fairly standard (maybe 15 degrees, though I don't have it with me right now, and I currently have it cold fitting down to around 3/4" from the final resting place). I could probably do the math for thermal expansion ratio and the like, but there are a couple of variables that are not necessarily clear (like how much drifting of the slot can be expected from hammering it into place). Any experienced folk have a general rule of thumb for this? I'd like to get it close before I do the final shaping on the guard. Thanks.
  13. Dan Hertzson

    Propane Fume Extraction in an Ancient Small Shop

    As propane is nominally heavier than air, the ideal fume extraction from your shop will have both high and low inlet points to handle both the heated combustion products and a potential propane leak (I burn natural gas, so only have a high exhaust). I personally have a 20 x 20 shop and use an almost 10,000 CFM, 1/2 HP sidewall exhaust fan and run a ton of air through my shop. This type of fan is ideal for the application, high volume and low static. More is definitely better, and my general assumption is that you don't need a hood with a natural gas forge as both the hot exhaust products and any leakage should rise. My fan is placed in the sidewall of the shop, high up in the roof peak. You certainly don't need anywhere near that much ventilation, but I find that it also helps keep the shop a little cooler.
  14. Dan Hertzson

    Propane Fume Extraction in an Ancient Small Shop

    You may not necessarily need to go with an expensive BIF Axial fan. A centrifugal utility set fan will also have the motor out of the airstream and can often be sourced at liquidators. You will need to be more creative about the duct runs, as they are not inline fans, but it should still work for you (there are also less expensive inline centrifugal fans that are belt driven, with the motor out of the airstream, but those are less common. Note that for fume extraction you don't necessarily need to worry, but if you are anticipating any kind of dust (in particular wood dust or a combination of same with metal dust) I would look carefully into spark/explosion proof fans, spark arrestors, a water trap... A good rule of thumb for capture of fumes is to have at least 100 ft./min. at the crossection of the hood entrance (i.e. if you have a 2' x 4' hood inlet you should pull 800 CFM at the fan and typically use a 12" diameter duct to connect them, the last depending on the external static pressure the fan will exert). A louver in a window or door will allow the makeup air you need to compensate for the exhaust. Typical velocities to avoid entraining weather are in the neighborhood of 500 FPM for a conventional louver and 800 FPM for a special drainable louver.
  15. Dan Hertzson

    Mini-Anvils, Possibly For Sale

    Any chance you could make some with a hardy post cast in place on the bottom (perhaps leaving a sprue or similar)? Would make a lovely usable tool...