The Newbies Arena Are you new to knife making? Here is all the help you will need. |
11-18-2016, 06:58 PM
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Member
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Join Date: Nov 2010
Posts: 27
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Need Help on Bowie Knife Blade
I am hoping some of you "veteran" knife makers can give a beginner a helping hand on this knife. Its a gift for a nephew who asked for a big Bowie, and I am in the final stage of its grinding and assembly. I just got the blade back from heat treat, and I need to decide how to finish the blade. The primary bevel is ground at 120 grit with about a 4 degree angle, and the edge at .04" width. I will finish with a 20 degree secondary cutting edge. Ordinarily, I might take the blade up to about a 220 grit on the grinder, then hand sand to a satin finish at about 500 grit. Except with this blade, I have struggled keeping a straight plunge line due to the longer length of the blade. In time, I hope to overcome this inexperience with a longer blade, but I don't have the confidence to go back to the grinder and not mess it up. I have practiced on a few other prototype blades, with mixed reviews. See photos. The first photo is the Bowie back from heat treat and dry fitted. The second is my prototype with some pretty nasty gouges. The third shows the edge width, which is about .04" inch. My inclination is to hand sand the rest of the way, then grind the final edge when the desired satin finish is complete. (lot of hand sanding!) Anyone agree or disagree? Your suggestions would be greatly appreciated!
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11-18-2016, 07:40 PM
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Guru
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Join Date: Aug 2015
Location: ny
Posts: 1,438
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I would say go back to the grinder and do it very very slow calculate every move, I remember when I was very very new i started a blade for my dad it was full flat grind but still i wanted that grind like perfectly up and down. i went very slow every pass i stop looked at what i was doing put the blade up close to the platen looked at it from all angles even from behind and did a pass then repeat, yeh it took a long time but it came out great and it helped my grinding for the future. BUT if you really don't want to go back to the grinder there isn't many other options than to hand sand as far as a satin finish goes, there are other things you can do i have played around with acid etching blueing and even cera coat, if you want the satin finish what will work quicker than sand paper is diamond compound from boride abrasives, it was recamended to me and i love it the lower grits "smeared" on a piece of leather will produce that satin finish quicker than sand paper and its a slightly different look personally i like it, also the higher grits on a buffer make quick work for a mirror finish.... but i bet you could do it quicker on sand paper than the time it takes to order i diamond compound
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11-18-2016, 08:14 PM
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Founding Member / Moderator
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Join Date: Jun 2002
Location: Wauconda, WA
Posts: 9,840
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My first rule of thumb is never take on a time sensitive project for a type of knife you've never built before. Generally, the results are less than stellar. Still, I know this one is for a relative and you have a great start on it but keep that in mind for the future.
Search out information on 'draw filing'. You can use those techniques to remove metal if you need to or you can substitute sandpaper wrapped around a steel bar for the file and do your finishing work. The easiest and most reliable way I know for the relatively unskilled to maintain a straight line on a blade that large ...
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11-18-2016, 09:25 PM
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Guru
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Join Date: Jan 2016
Location: Now live in Las Cruces NM.
Posts: 1,345
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Listen to Ray and Dave as I finish my big knives that way. I use sandpaper glued to hardwood sticks to draw file as they say. I can't recommend how I finish grind them to you as it is just something I do, but I use an angle grinder with 220 grit paper glued onto old discs. I know crazy, but I've done it for decades now.
The wet dry sandpaper is silicon carbide and a thin cutting oil works well in the initial material removal stages with low grits like 180-220, it really does take it off better than with water. Final 400-600 finish use water as it's just easier to see your lines as the oil makes everything black as it removes the material.
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11-19-2016, 06:51 AM
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Member
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Join Date: Nov 2010
Posts: 27
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Very good advice from all. I appreciate it. Yes, i will be more mindful of what I promise in the future! Thanks again. I think I will try hand sanding with a flat bar I have used on previous knives. It will definitely be slower going, but the safer route at this stage in the process and my own development. Thanks again.
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Tags
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angle, back, beginner, bevel, blade, blades, bowie, bowie knife, edge, grinder, grinding, hand, heat, heat treat, helping, how to, knife, knife blade, knives, makers, material, need help, sand, sanding, satin finish |
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