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Post by mikejapan on Aug 3, 2011 1:45:34 GMT
Hey guys, My O-katana has an edge right. It can cut paper but when I put my thumb on the edge and apply pressure while going down the edge it flat out doesn't cut me... I don't REALLY want to sharpen it. Even though I already tried for 8 hours through out the night and falling asleep at 10 this morning... Didn't really yield results. I'm just polishing it all over again for now. I used Wet n' Dry sandpaper with varying grits from 400 all the way up to 2000 so far but still needs ALOT of work. I was wondering if anyone could help me with this at all. And no, i'm afraid of giving it to a guy who just sharpens kitchen knives and what not. Thanks, Michael
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Post by Dan Davis on Aug 3, 2011 1:48:25 GMT
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Post by mikejapan on Aug 3, 2011 2:10:54 GMT
Thanks Dan
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Post by ineffableone on Aug 3, 2011 6:59:14 GMT
Dan's link goes over this mostly though in more detail and complexity.
I was going to answer that a good convex might not feel "thumb sharp". While it will cut mats bottles and other stuff, it does not seem sharp to the touch.
This is a simple version of what the link provided sort of says. Though my version is very very simplified and put in very basic terms.
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Post by mikejapan on Aug 3, 2011 7:07:49 GMT
Thanks ineffableone! Sad thing for me is.... I can't cut plastic water bottles worth crap. I think it's my velocity with my O-katana. I hit it dead on and I practice my cuts quite often but it just bats the bottles away with the cap flying off :/ But other targets like milk jugs or something with more weight I usually kill with ease I should probably invest on getting a REAL sword cutting stand as well
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Post by ineffableone on Aug 3, 2011 10:44:16 GMT
How are you cutting?
Are you baseball bat swinging?
Are you cutting horizontal or at an angle?
Do your practice swings get the audible feed back?
Are you slicing with your swing?
Are you aiming at the target (water bottle) or past the target?
These are some questions to consider for your bottle cutting technique. You might want to check in the backyard cutting section here, and watch some of the videos to get some ideas of what others are doing?
Some things I would suggest. Practice your cuts without the water bottle.
Make sure your getting that audible feedback (whistle) as you swing the cut in the air.
Horizontal cuts are more difficult than angled cuts and require better edge alignment plus sharpness. I would suggest you try angled cuts while trying to get your technique down.
Try slicing as you swing, your off hand "pulling" the blade toward you as your lead hand swings the blade in an arc toward the target.
Make sure your aiming for a few inches past your target. In other words don't aim for the center of your target as the end of your swing. Aim for swinging through the target past where you would have cut.
Oh and one other thing, find the sweet spot in your blade, that one best harmonic area where you get the best cutting.
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TomK
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Post by TomK on Aug 3, 2011 19:19:00 GMT
Michael, I was just sitting down to try and reply to your PM (sorry it has taken so long) when I saw this thread and thought I'd just do it here. that Bugei link is pretty good, also check out www.nihonzashi.com/diy_is_my_sword_sharp.aspxsharpness can be a tricky thing to identify. what I like to do is to place the flat of a fingernail gently on the edge and scrape the blade across the nail. kind of like I was trying to shave hair off the nail with a razor except the blade should be at a 90 degree angle to the nail (because you don't want to whittle your finger). if the edge tries to catch the nail and if you can scrape a little bit up then it is sharp. the sharper the edge is the more agressively it will bite into the nail so be careful. if it slices paper smoothly you probably have a decent edge on it, but try the fingernail test if your nail slides across the edge then it needs to be sharpened but if the edge catches even a little bit and scrapes up some nail it is at least ok. the thing is that the angle of the edge can make a large difference in how it feels and if the angle is wide enough it will feel like it won't cut you even though it can and will. another thing that can make an edge not feel sharp to the fingers is if it is polished well on the edge making the edge very smooth. I have felt edges so smooth they feel dull until you realize that you just shaved off a flap of skin with that dull feeling edge. try the fingernail test, look for flat spots and rolls like mentioned in the nihonzashi article. you can use your fingernail to find a rolled edge too as it will scrape in one direction and not the other. good luck
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Post by mikejapan on Aug 3, 2011 21:36:41 GMT
Thanks guys, ineffableone What IS baseball swinging? Hands to close to each other? Stance?? I practice dry cuts quite often. I do get audible feedback 99% of the time I haven't tried the slicing one yet. Pulling your hand back to your body. I do cutting at many angles. TomK, THANKS for replying on here. Anyways. I did perform the fingernail test. The edge on mine is pretty smooth. All I caught were the two miniscule chips. But it didn't cut into my nail... It has to be somewhat dull but isn't that kind of a good thing? It won't chip as easily right? Michael
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TomK
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Post by TomK on Aug 5, 2011 0:50:10 GMT
I don't know Mike, sounds like you got a dull blade. I'd start with draw filing since you have had such little luck with paper. if the file slides off then use a whet stone. I suspect you may have flat spots. the edge of your sword should be invisible when you look straight down on it (good edge alignment to cut your eye) if you can see the edge at all it is flat and you need to bring the two sides together. a file or coarse stone is the way to do this. paper would work but can take a long time
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Post by ineffableone on Aug 5, 2011 1:56:46 GMT
Yep sounds like your blade is not that sharp. I would suggest following Tom's advice for sharpening it up.
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Post by mikejapan on Aug 5, 2011 3:54:24 GMT
Well, you guys really helped me out on this. I appreciate it! So, what kind of whetstone are we looking at here?
Michael
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Post by mikejapan on Aug 5, 2011 4:55:44 GMT
So would this be good??? www.trueswords.com/smiths-three- ... -3987.html I'm having a dilemma with the edge. I actually like how it's NOT so sharp because it can take much more abuse. I know it's a DH blade and will of course hold a better edge but can be brittle. What do you guys think? Michael
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Post by ineffableone on Aug 5, 2011 5:19:12 GMT
Yes you can use a tri stone like that one. There are also many other techniques. Try looking in Tom's signature, there is a link there to his sharpening tutorial.
There are also a lot of tutorials on youtube for convexing a knife edge. Many of these can help give you an idea of what is needed. There are some but less for proper sword edge convexing on youtube.
A good convex edge still is pretty durable and you don't need to worry so much about it. In fact this durability is one of the things that makes convex edges so desirable.
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Post by Brendan Olszowy on Aug 5, 2011 14:25:10 GMT
I havent read the full thread but my first reaction is to the wet and dry. I don't recommend trying to sharpen with papers; because they are soft and tend to kind of wrap over the edge rounding it as it goes, actually making it blunter. I'd recommend honing the edge with a flat hard surface. I use arkansas stones - usually a hard one (fine) while a soft (coarser) arkansas can help cut down a blunt edge. A super fine diamond plate can do a nice job honing the edge too.
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Post by GUEST on Aug 5, 2011 15:10:22 GMT
Yes a morgan edge isn't easy to do, but there are alot of people who can do it.
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Post by GUEST on Aug 5, 2011 18:04:24 GMT
I can tell you I'm not confused, After thousand of years of people sharpening metal I doubt if you have came up with a new way to do it. The way you tell if it is a morgan edge or a slight mod. there of. Have the same edge on my old Cold Steel Trail Master Bowie back when they were made in the US out Carbon V steel. IF to can do a morgan edge on a sword I salute you it is a difficult edge to do, problaby worth the price you charge.
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Talon
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Post by Talon on Aug 5, 2011 18:17:53 GMT
im interested in just what sort of profile ricky puts on his blades,ricky heres a link to the various edge geometries commonly found on katana,(as well as some knife grinds just ignore those) so if you could tell us which profile is closest to the geometry you use,or better yet a cross sectional diagram so we can see just what sort of edge you mean,a picture says a thousand words,and it will help those of us who are curious understand you're finished edge profile and how it differs from the rest currently used,also the degree of the bevel would be usefull to know aswell www.toyamaryu.org/edge_geometry.htm
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Post by Dan Davis on Aug 5, 2011 19:16:10 GMT
I am just curious - what is a "morgan edge"? I've been doing this for 38 years and never heard of a "morgan edge".
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Talon
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Post by Talon on Aug 5, 2011 19:22:20 GMT
me too,i thought i knew all of the various grinds,but its a new one on me,and my google fu isnt bringing anything up :?
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Post by GUEST on Aug 5, 2011 19:26:30 GMT
Maybe I'm using the wrong name Bagwell used the edge on his bowie knives, of couse Cold Steel copied it in thier older Trail Master Carbon V bowie.
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