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Flat grinding


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Anyone know of any good tutorials on flat grinding? Try as I might, I can't get an even grind without convexing the edge or creating digs in the surface.

 

Am I grinding impatiently? Too high a speed? Too much pressure? Piss-poor technique?

 

-Jim

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In short, yes.

 

 

 

:ph34r:

 

 

 

I find that a clean fresh belt, a light touch, and a ton of patience are key to getting it right in my shop. Mind you, I'm using a cheap grinder, so results will vary with quality of equipment - it may be easier on a pricey KMG or something. There is some technique to "finding flat", which generally involves sneaking up to the belt edge-first, but how you hold the blade, support it against the belt's motion, and apply pressure into the platen will determine the cleanliness of your grind. A good, consistent grip that doesn't stress your hands or wrists is important, as is frequent checking of your angle.

 

 

Good luck - come over sometime, I'll be happy to work with you on it.

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http://tinyurl.com/7punw76

this video helped me alot

especially the use of a push stick.

notice how he uses the stick in different height levels of the blade and how he keeps it in the middle of the platen and pulls the blade across the pressure of the stick.

This has really helped me and my grinds have gotten a lot better and easier.

Also the use of a tool rest.

Good luck

JJ

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i have a couple of cheap grinders, 4x36 and 6x48, with wide flat platens - i hog off most of the material with my big 2x140 grinder, and then switch to the wee ones to true up the flats. the wide horizontal platen really really helps; i don't really get vertical platens as you have nothing to work off, whereas with a horizontal platen you can feel if your blade is horizontal.

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Very wise words there, Howard. Each person has to develop a style that matches the maker and their equipment. I guess that's one of the reasons that I get a little put off by articles that say essentially "this is the way that I do it and this is the way you need to do it" instead of "this is the way I do it and you might give it a try to see if it works for you".

 

Doug

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One thing that has helped me tremendously is to use a contact wheel and hollow grind the bevels first. Yeah. Yeah. I know, it sounds counter-intuitive but, let me explain. The contact wheel will remove metal more efficiently than trying to grind the entire flat because the area of the belt that touches the steel is smaller. The belt also gets bent around the contact wheel and this "opens" the grit of the belt up. After you have established the bevels on the contact wheel you can then switch to the flat platen and the bevel will be easier to keep flat because it cannot rock or pivot on the material in the center of the bevel. It also will be faster to grind because you are not removing as much material. Having less surface area in contact with the grit also seems, to me, to give better control because there is not as much "grab" from the belt trying to yank the blade around. Also, it really helps to use the tool rest. Things are much more controllable when you use one because again, you are not having to fight the "grab" from the belt.

 

~Bruce~

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I agree with Jake (and Howard) the 4x36 set up horizontal (I prefer it running away from me is my preference) with a flat platten really helps getting things dead flat as you can lay the blade down on it (careful with swords as they can get bouncing and may need to be slightly flexed). One you get a good feel for grinding it isn't that hard to do the same thing on a 2x72 with the platten vertical and the sword horizontal.

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One thing that has helped me tremendously is to use a contact wheel and hollow grind the bevels first. Yeah. Yeah. I know, it sounds counter-intuitive but, let me explain. The contact wheel will remove metal more efficiently than trying to grind the entire flat because the area of the belt that touches the steel is smaller. The belt also gets bent around the contact wheel and this "opens" the grit of the belt up. After you have established the bevels on the contact wheel you can then switch to the flat platen and the bevel will be easier to keep flat because it cannot rock or pivot on the material in the center of the bevel. It also will be faster to grind because you are not removing as much material. Having less surface area in contact with the grit also seems, to me, to give better control because there is not as much "grab" from the belt trying to yank the blade around. Also, it really helps to use the tool rest. Things are much more controllable when you use one because again, you are not having to fight the "grab" from the belt.

 

~Bruce~

 

That makes perfect sense to me, I can't wait to try it.

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Practice, practice, practice. Ad nauseum.

 

I'd offer advice, but it would only be how I do it, and counteract nearly everything else previously said. Which would not help you. The only real answer IS practice, unfortunately.

 

I second, third, fourth it...Practice. You might also look into ABS Mastersmith Harvey Dean's DVD on Flat Grinding. It really helped me.

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I keep my platten tilted back at 45 degrees. I know most people have theirs vertical, but I can't hold the knife very steady that way. I get an angle set into the knife and then modify it as needed by applying slight pressure to the top or bottom of the blade. You will learn to feel when the blade is lying flat against the platen.

 

Wayne

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