Sharpening
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Kevin Hirata.
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13 December 2016 at 7:49 am #143298
I’m new to hand tools. Wanted to see if I could get some advise as to what I’m doing wrong when it comes to sharpening my chisels and planes.
I’m using DMT diamond stones. I start with x-course, then move to course, fine, x-fine, then XX-fine. I finish with a leather strop. I get a bur after a few strokes on the XC stone. I follow Mr. Seller’s instructions and stay on the bevel side of the blade all the way through the leather strop. I then flip the blade over and give the blade a couple of quick pulls on the back side. I can’t seem to get a sharp edge, or at least an edge which will easily slice through paper. Are two pulls on the back side of the blade enough to remove any bur? After stropping the beveled edge, do I need to hit the back side of the blade with the xx-fine stone to remove any bur? BTW, I have flattened the backs of all of my blades.
I’m quickly finding out that I need to figure out how to sharpen my blades before I can move forward.
Thanks,
Hi,
Try your planes for sharpness before you strop. If they are really sharp before, you are probably rounding over the edge on the strop (I was for a while).
If they aren’t sharp, go back to coarse and make sure you have an even grind on the face, even if you start to get burr you still need a flat, even grind on the whole face.
I tend to remove burr on each stone as I go, rather than use the strop.
Work up through the grits. each grit need to remove the coarser grinding marks from the previous stone, eventually giving you a smooth, mostly shiny but definitely consistent face.
Only then go to your strop.
Hope that helps
Darren.
Im not sure i understand the benefit of going back to extra coarse each time. ?? I only use that for squareing up or refurbishing other than that it would seem you are just wearing out your chisel quicker. The burr gets pulled off the flat/ back after the superfine stone, then on to the strop. Make sure you are not rounding over the edge by rocking the chisel on the strop. Just pull straight back, the leather will give but the stones do not. Watch the youtube/mc video again to make sure you follow the steps. Hope that helps.
I wouldn’t go back to extra coarse each time. Start at coarse. If you are getting a burr with just a few strokes, perhaps you are holding the handle at too great an angle. Get a small piece of scrap, cut it at 30 degrees, and put on your stone as a template for the angle to use. The block just sits on the stone at the far end. Hold your tool against it when you start to sharpen to make sure you have the right angle. You only need to do this for a few sharpenings, then toss the block. You should also get a protractor or brad two small sticks together and examine your bevel not so much to measure the angle but to see if the tangent to the bevel at the tip is around 30 degrees or if you are making a semicircle that is 30 degrees in the middle but much steeper at the tip. You may find that, to get rid of the hint of light at the tip of the tool when examining with the protractor, you must open up to a really big angle.
The other suspicion is that you are developing such a large burr that you aren’t really getting it off. After sharpening, put the chisel across the grain on the face of a hard wood like oak and hit it with a mallet. Now feel the edge for a burr. You may find it has come back, indicating that you didn’t really get it off in the first place. If you have the DMT XX fine stone, you can skip the strop as an experiment. XX fine will give you a usable edge. If that feels sharp enough to cut, then you know the problem is with rounding over on the strop, so correct your strop technique and work it back into your sharpening.
13 December 2016 at 8:08 pm #143326Thanks guys for your help.
I’ll try testing the blade before stropping to see how well it cuts. I think I am rounding the burr over while stropping as I sometimes feel a rounded ridge over the back edge of the blade when I am done.
I forgot to ask another question. How much pressure do you put on the blade while sharpening? Do you easy up as you get to the higher grits?
Thanks,
Kevin
Also, if you need to hog off a large amount of metal from the blade (if you are restoring an old plane for example, or you hit a nail etc.) go for 120 grit sandpaper on a flat surface first, before your extra course stone, it will grind fast and save your stones.
You need a fair bit of downward pressure, you are trying to remove metal, but not so forceful that it limits the fluidity of your sharpening movements. You will hopefully develope a natural rhythm. I still on occasion have to remind myself to pull straight back and not roll on the bevel when on the strop. Watching paul’s video on you tube a few times and then a few more helped.
14 December 2016 at 3:04 am #143342What Brian said – put enough pressure on the tool during sharpening while still being able to control it. I’ve been at this a few years and still have not mastered it. Keep working at it. It gets better. Experiment with things like others have suggested.
14 December 2016 at 3:32 am #143344BTW Kevin, you live in the town where a local Bay Area woodworking club (BAWA) meets one Thursday a month. They could be a great resource for you. I joined a couple years ago, but couldn’t continue going because I just can’t get there from where I live (Mt. View) unless I’m willing to sit in traffic for 1.5 hours.
14 December 2016 at 4:11 am #143349Hey Matt, thanks for the heads up. No kidding about sitting in traffic for 1.5 hours.
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