Differences in grinding technique - sword vs knife fabrication

Discussion in 'Shop Talk - BladeSmith Questions and Answers' started by Black Cat, Feb 13, 2021.

  1. Black Cat

    Black Cat

    14
    Oct 14, 2020
    I’m a little bit new to sword making, and really knife making also. I’ve gotten hooked and doing some small knives on a 2x72 belt grinder. My real interest is in making swords and really looking forward to starting that also. I was interested to know if there are any differences in technique or just general construction of grinding swords vs knives. For example, one of the things I was wondering. Since your hogging off a lot more material with swords, would you want to run the belt at a higher SFPM speed compared to when knife grinding? And would it be advantageous to use a really big contact wheel (ie the bigger, the better) when making swords?
     
    Last edited: Feb 14, 2021
  2. BitingSarcasm

    BitingSarcasm Basic Member Basic Member

    Feb 25, 2014
    Swords are not just long knives. Cold Steel, for example, makes thick, heavy blades with minimal distal taper. They are like an extended knife blade in a way, and they can be awkward and ungainly. Then you pick up a sword that has distal taper and feel how lively it is, yet it is still strong enough for aggressive chopping. Good grinding will make a prybar into a sword. You have specific questions about crafting techniques, so it might be more enlightening to post in the knife maker’s area.
     
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  3. Black Cat

    Black Cat

    14
    Oct 14, 2020
    What about a wider work rest? I’m a little bit concerned about making the bevel nice and straight especially with a longer blade. With small knives it’s easier to hold. Anyone have any pics? What’s the easiest sword, or maybe least c9mplicated, to start out trying to make?
     
    Last edited: Feb 14, 2021
  4. Black Cat

    Black Cat

    14
    Oct 14, 2020
    <edit> accidental duplicate message. Please delete.
     
    Last edited: Feb 14, 2021
  5. Stacy E. Apelt - Bladesmith

    Stacy E. Apelt - Bladesmith ilmarinen - MODERATOR Moderator Knifemaker / Craftsman / Service Provider

    Aug 20, 2004
    Actually, there is more hand work with a sword. Draw filing, using an angle grinder, lots of hand sanding. As far as the grinder goes, You need a wider work rest for swords. It is hard to get a perfect even grind with the grinder, which is why there is more hand work in the finishing.
     
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  6. Joshua Fisher

    Joshua Fisher KnifeMaker / Craftsman / Service Provider Knifemaker / Craftsman / Service Provider

    669
    Mar 27, 2018
    I do hollow grinds even on swords so I can’t give advice on how to do a flat grind on a sword blade though in concept it should be the same, I currently use a 10” contact wheel with no work rest. On a straight blade I scribe a centerline from ricasso to the tip and scribe marks along the edge for my edge thickness, I start off grinding at a steep angle (25-30 degrees) down to my edge line then I work the grind back to my centerline, I work in multiple sections then blend those together. The straighter the blade the longer the section I can usually grind. If you follow that with a contact wheel you’ll have a nice diamond cross section down the whole blade it’s a very basic grind and you can make improvements based off that. Start off with some daggers or short swords like a small arming sword to get the basics of grinding blades of that type, I’d suggest starting off picking western or Japanese style swords and learn how to properly grind one style then move on to the other of you want to broaden your capabilities. Now back to the example of a arming sword and the basic grind from above here’s some ways to improve on a basic grind, the first thing is distal tapers, most swords have a distal taper to improve balance and weight meaning the ricasso closest to your hands in theory should be the thickest spot on the whole blade, there are two main ways to accomplish this, you can grind the distal taper in while the blade is flat before bevels then you go back to the method described above using a center line and only grinding to the center line. The second method for adding a distal taper is grinding past your centerline as you go down the blade on your first side, for example say at the base of the blade it’s 2” wide at that section you would just grind to the centerline 1” in from the edge, if you continue to grind 1” in from the edge all the way down one edge you are gradually tapering the blade because when you go to grind the other edge and you start to push the ridge line back in the middle more material will have been removed from the middle the further down the blade you go. For swords one of the biggest differences I’ve found is the amount of layout I do, on knives I normally just scribe and edge line but on swords or daggers I scribe edge lines, center lines, lines to create tapers, and often times I’m re scribing certain lines multiple times. Another way to improve beyond a simple diamond cross section with a distal taper is to add a fuller in the middle of the blade, it’s another great way to get weight and balance where you want, fullers need to be ground with a wheel and should be done before beveling, it seems to be a preference on grinding a fuller before tapering a blade if you grind it before you have to grind the fuller longer than you want but the end of the fuller were it feathers out into the taper looks good, if you grind it after you don’t have to grind as far but your end transition has to be ground well to look good. Hopefully some of this helps, long story short swords are much more complicated than knives and I recommend trying to recreate historical swords where you have measurements and weights to work with to get the basics down. Also if you have a 2x72 I much prefer grinding swords after heat treating as it’s much easier to straighten warps on a flat piece. Also Stacey thank you for the advice on the sickle sword build I ended up rechecking and I had enough clearance to grind the edges on the grinder but I definitely am thinking about picking up some expansion wheels for odd jobs. AB5CA33C-3090-4211-9083-4E26B928CF32.jpeg
    DDDE07D9-7F20-49E8-ACA4-0E0AEBD95F1E.jpeg 8F900C02-B009-4290-B4F4-4E8D249DB360.jpeg
     
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  7. Richard338

    Richard338 Gold Member Gold Member

    May 3, 2005
    Joshua gave some good tips. I have made a katana, a viking sword, a waki, a few tanto, and several daggers.
    The easiest sword length piece by stock removal is the katana. This is assuming that your blade profile is a simple convex right to the mune (ridged spine).
    To answer your question, I don't run the grinder differently, but remove most of the material with a fresh 36 grit ceramic belt. I mostly use the platen, not the wheel.
    A traditional style katana has no plunge and so the grinding is easy, running back and forth, long passes right over where the handle will be, slower to build up heat.
    There are other challenges later like fitting a habaki etc, but the actual grind is easiest.
    You can stop grinding when you have gone as far as you dare without screwing up and then finish by hand.
    The less skill you have or more cautious you are will mean more work by hand (I often leave quite a bit to do by hand).

    More difficult is having a long bevel that doesn't reach the spine, and keeping the height even.
    For daggers, Joshua mentions either putting in the distal taper first, or achieving it by iteratively over grinding and evening out the center line.
    This is not an either/or choice in my experience. Unless your taper and profile match perfectly, even with the taper put in first, you might have sections that take some finesse to bring the ridge together and you will likely do some refining of the center in any case. I do prefer to put in most of the taper in advance. It is easy to mark the blade at intervals and run it under a wheel to hit the desired taper values.
    Good luck and post some pictures.
     
    Last edited: Feb 14, 2021
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  8. razor-edge-knives

    razor-edge-knives Moderator Moderator Knifemaker / Craftsman / Service Provider

    Apr 3, 2011
    Good tips above... Also, check out Kyle Royer, he's video documented a few sword builds that are awesome to watch

     
  9. Black Cat

    Black Cat

    14
    Oct 14, 2020
    Wait a minute. Joshua, you heat treat before you start grinding? I get your rationale of it being easier to straighten warps on a long section, but would you then heat treat after finishing also? I don’t have a way to heat treat economically so I’d have to outsource that after I’m done.

    Lot of great tips. Thank you all. I see that some prefer using a very large contact wheel and some prefer using a platen. I’m thinking of switching over to a large contact wheel, but I’m afraid that I won’t be able to support the blade well due to getting a little fatigued from holding up a larger piece to grind. Isn’t it a lot harder to get a nice consistent and even bevel doing a much longer blade?
     
  10. Natlek

    Natlek

    Jun 9, 2015
    Get some 2x2 inch tube long enough to support your sword , mark center line on your sword , clamp it to tube and grind bevels .I can t see any difference in grinding 5 , 10 inch long blade versus 30 inch blade .You don t need 3 foot long or foot wide work rest to do that .
    Only difference I can see is time it takes to do that.
     
  11. Joshua Fisher

    Joshua Fisher KnifeMaker / Craftsman / Service Provider Knifemaker / Craftsman / Service Provider

    669
    Mar 27, 2018
    You only need to heat treat the blade once, some people like to do most of the grinding before heat treating while the steel is soft and if you are using hand tools like files or a small belt sander like a 1x30 or 2x42 then it’s easier to do most of the grinding before heat treating then do just the finished grinding after heat treating but there is more chances of a warp that can be more difficult to fix if your grinding is not even. I prefer to heat treat the profiled blade then grind the bevels in so I only have do it once versus twice and it is easier to keep the blade nice and straight. I also find since the material is harder the feedback from the grinder is better than with soft steel I feel like I can feel what going on and am less likely to remove material where I don’t want to. It’s very important when grinding post ht to keep the blade cool by dunking it in water, I use sharp belts and low grits to do 95% of the work, both swords I posted above were ground with Norton 36 grit blaze belts then polished with scotchbrite belts, if you take your time on the rough grind the polishing is easier but if you rush the rough grind you may need to refine things by going up to higher belts before a scotchbrite belt. I don’t do hand sanded finishes but if I was I’d start with 36, 60, 120, then move to trizact belts 180, 280, 360 from there you could start hand sanding at 220 if your grinds are good and go up how ever far you want. If your grinds are really dialed in you could go up to 600 in the trizact then start hand sanding at 400. Holding a heavy blade can be a arm workout but you don’t have to do it all in one go, on that arming sword I worked in 6-8” sections down the blade so I’m holding my hands maybe 12-18” apart. You can also grind a side then set it down and come back to it. If you learn to freehand grind you won’t ever be limited to what a jig can do, if you only use a jig you may find the muscle memory doesn’t necessarily translate fully.
     
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  12. Richard338

    Richard338 Gold Member Gold Member

    May 3, 2005
    Fantastic video, I got more and more impressed as it went along. I've done the poor man's version of a few of his techniques. It was nice to see a master. I also like how happy he was when each piece came out how he hoped.
     
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  13. Black Cat

    Black Cat

    14
    Oct 14, 2020
    Got dang! It’s been a catastrophically bad week. I’m just getting back online after no electricity and heat for days. I’m in TX and our dumb government powers that be decided that all us Texans should be on an old curmudgeon electrical grid system that completely is prone to failure when demand for electricity is too high. My family almost died of hypothermia because of those idiots. We had no heat for too long during the worst winter storm for us in a decade. Sorry, I digress.

    Why doesn’t anybody make a 4x72” grinder for sword makers? When I went from a 1x48” grinder to a wider 2x72” grinder, I could definitely feel the stability and evenness of a wider belt. So, for making swords why don’t we see a 4x72” grinder, or even a 4x79” grinder as 4x79” is actually a fairly easy to find belt that comes in many grits. The 4” wide form factor would be even more stable and can make quicker work for a long sword. So, why haven’t any 2x72” grinder makers produced a 4x72” grinder? All it would require is to convert the 2x72” with wider wheels. Anybody think there is a market for that?
     
  14. Stacy E. Apelt - Bladesmith

    Stacy E. Apelt - Bladesmith ilmarinen - MODERATOR Moderator Knifemaker / Craftsman / Service Provider

    Aug 20, 2004
    They do make larger grinders. Burr King has industrial models in 3"X79", 4" X60", and a 2.5"X60". The 60" models are made for wet grinding and have VFDs.

    72" belts are available from most major manufacturers in 2", 2.5" and 3" from most belt suppliers. You would have to change out the wheels to run a 2X72 with wider belts.

    I have a 0-750RPM 2.5"X36" unit I made for sharpening. I also have the wheels for a future 3" grinder project with a 5Hp motor. I still have to build the tracking unit.

    One thing I failed to mention earlier is :
    When working on sword length projects, it is really nice to have a grinder that flips to horizontal. Some folks make a dedicated horizontal grinder with a long rest and long flat platen. They usually put a 4" wheel on one end of the platen and a 2" wheel on the other. The work table wraps around both wheels.
     
  15. PEU

    PEU Gaucho Knifemaker Knifemaker / Craftsman / Service Provider

    938
    Aug 6, 2006
    Talk about a warped blade, what's your technique on straightening :D:D:D

    Pablo
    PS: amazing work!
     
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  16. Sam Salvati

    Sam Salvati

    Aug 6, 2007
    It’s usually approached two different ways, either small bites up and down the blade then blend everything together, or ground as a whole. Really depends on the type and way you are using a grinder. Platen, Vertical on a wheel, sidewayS on a wheel.
     
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  17. Joshua Fisher

    Joshua Fisher KnifeMaker / Craftsman / Service Provider Knifemaker / Craftsman / Service Provider

    669
    Mar 27, 2018
    Haha thank you, funny enough i was working on a different sword and when I quenched the blade the tongs slipped and the blade fell into my quench tube, I thought for sure the tip would be broken when I finally got it out but it just had several bad warps from the fall so I re did the ht only to have it warp sideways and added a significant curve to the blade, I want to say it started with a 32” blade and ended up at 30” to re center the tip and centerline. Since then I’ve done all my grinding post heat treating and haven’t had to deal with any major warping and if a blade does warp the flat material is much easier to safely flex and correct. I’m starting to play around with some w2 steel now and messing with hamons and eventually I’d like to make a traditional Japanese Katana or Wakizashi.
     
  18. Black Cat

    Black Cat

    14
    Oct 14, 2020


    Interesting. I’ve seen the Burr King. It’s a damn nice grinder, but too rich for my blood. I like the simplicity of the 2-wheel grinder though. There’s a lot of plan out there for more common multiple wheel grinders in a 2x72 format. I could possibly fabricate a 2 wheel grinder similar to the Burr King, but I don’t trust my fab skills too and planning much without seeing an open source sort of plan for a 2 wheel grinder.

    Anyway, where did you find the 3” wide wheels you plan to use for your future 3x72” grinder? I haven’t seen those for sale anywhere. If it’s custom, that g7ves me another thought. I could potentially just convert a 2x72” grinder with 3” or even 4” wide wheels just by replacing all the 2” wide wheels. What are your thoughts about that?
     
  19. Stacy E. Apelt - Bladesmith

    Stacy E. Apelt - Bladesmith ilmarinen - MODERATOR Moderator Knifemaker / Craftsman / Service Provider

    Aug 20, 2004
    Yes, that is what I aid:
    72" belts are available from most major manufacturers in 2", 2.5" and 3" from most belt suppliers. You would have to change out the wheels to run a 2X72 with wider belts.

    I got the wheels from a machine shop that was closing. They had contact wheels up to 12" wide.
    You should be able to get them from places like industrial suppliers (McMaster-Carr?).
    I'm sure Sunray has wider contact wheels.
    Also, any good machine shop will make the aluminum wheels for you.
    I bet Greg at Reeder will make a set. You could probably order his basic chassis with the wider wheels. Give him a call.
     
  20. Natlek

    Natlek

    Jun 9, 2015
    This is first dagger i ever grind .It is from file already tapered , i mean factory taper shape towards the tip of file . Grinding bevels was same as on ordinary knife , just follow center line .Without that taper would be little more complicated to grind ,at least to me .
    [​IMG]
     
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