Wednesday, January 21, 2009

Sharpening with Scary Sharp

Sharpening tools is a critical skill. Dull tools don't function properly (or at all) and lead to frustration. Being frustrated is not fun. Woodworking should be fun. So, learning to sharpen is paramount.

There are a lot of methods or systems out there - water stones, oil stones, motorized platters etc. Find a system that works for you. I got lucky and found the Scary Sharp system just as I got into hand tool work. It works great!

What is Scary Sharp? Well, basically it is sandpaper on glass. That's it.*

The first key is that the abrasive paper has to be glued FLAT to the glass (which of course also has to be flat). I do this with a thin coat of spray adhesive (nasty stuff - use outside). I have heard that some people just use water to temporarily stick the paper to the glass - I don't trust that idea, but of course, I could be wrong. If the paper is not flat, you will round over your edge, defeating the whole point of sharpening.

Another key is to progress through multiple grades of abrasive paper. The more grades, the less time on each grade to remove the scratches from the previous grade, and the whole process goes smoothly. Done right, Scary Sharp is not slow. It takes me less than a minute to refresh an edge. A couple of minutes if I need to redo a full bevel.

In an effort to eliminate any excuses to postpone sharpening, I made a dedicated sharpening station. This takes up precious shop space, but is very convenient, allowing me to sharpen whenever I want with no set up. I walk over to the sharpening bench, sharpen, and get back to work with a sharp tool.

On the top is the Scary Sharp system. Four glass plates with abrasive paper attached. Left to right the plates have 180/220, 300/400, 500/600 and 1000/1500/2000/2500 grits respectively. The other sides of the plates have coarser grits for heavier work, but I don't use them nearly as much.

On the shelf underneath are various other sharpening related materials: saw vises, hand grinders, various honing guides (The Veritas Mark II is great, but shortly after getting it, I decided to make the leap to honing by hand - much, much simpler!), my Granfor Bruks axe stone (I use it on my drawknives - love it!), large black markers, a box of small strips of abrasive paper for sharpening curved irons, and various dowels and small pieces of wood to be use with the strips of sandpaper. And my Norton Water stones live down here too. I got these a couple of years ago when I though maybe there might be something better than sandpaper. I mean, a lot of people swear by them, so I thought I would give them a try. Yikes! Awful! What a mess, and I couldn't even come close to what I could do with Scary Sharp. I gave them a couple of days, and then packed them up. I'm either going to sell them on Ebay or break them up to make slips for the carving chisels I don't own yet. I'm sure I could get them to work eventually, but why bother? I'm just glad these weren't my first experience with sharpening when I started years ago!

A brief example of the system in use.

Here's a plow plane iron from Ebay. First I want to check to the back for flatness. Using a black marker, I coat the last inch or so.

After about five strokes on the 220 - the thin black line at the edge shows a clear back bevel on the iron. Not what I was looking for. Now I have more work to flattening the back before working on the bevel. It's time to flip the plates over to the coarse sides.

After about four more minutes on the lower grits - that's more like it. Now I can flip them back over and work my way up the higher grits.

One minute total on the fine stuff and it's a mirror! Now it's time for the bevel.

Since I am not shaping the whole bevel, I only care about the very edge. The paper cuts fast, and it's easy to overdo it. Only a few strokes each grit and it has a tiny polished bevel. Combined with the flat, polished back, that equals a very sharp edge. Scary Sharp in fact!

And a final shot of the iron at work in the plow. The shavings are still on the rough side, since there is no chip breaker and no real mouth on this plane. So the result of having this iron truly sharp is not a matter of leaving a fine finish like it would be in a smoothing plane, but I can sure feel the difference in the effort it takes to plow the groove.

Total time spent was about 7-8 minutes, and most of that was flattening the back which I will never need to do again. What's more, the sheets of abrasive paper are getting old and will need to be replaced soon. Then it really works fast!

I know the Scary Sharp system is not for everyone, but it works great for me. If you are just getting started, give it a try. It's inexpensive and easy. Or if your current system is not making you happy, give Scary Sharp a shot.

*If you Google "Scary Sharp" you will find a lot of information, but one of the best places to start is here: Rod Peterson is a galoot who has posted a duplicate of the now defunct original "Scary Sharp" page and also has information on the origins of the technique. Thanks Rod!


  1. I gotta say Dan, your post is making me seriously consider trying Scary Sharp! I've been using waterstones, and am generally happy with them. But you're right, it is a mess, and to be honest I procrastinate sharpening a lot!

    So I'll give it a shot. Great post!

  2. That is one of the methods I haven't tried yet. I have only used rough sandpaper to flatten plane soles.

    It's so true that having a designated sharpening area makes it easier to keep your blades sharp. Nice write up, Dan!

  3. Eric - I am with you on the procrastinating - I found that if I had to do even ONE thing in order to sharpen (like say getting supplies out of a drawer) that was enough to make me put it off! I'm so lame!

    I think that one of the reasons I struggled with the water stones was because I used too much pressure. I'm not sure, but they dished out FAST. I spent more time flattening them than sharpening. I think this is because I was used to scary sharp, which is very forgiving of pressure, since the abrasive stays flat. I'm not totally sure...

    Kari - I'd be curious to know what your experience is when and if you try it. It's about perfect for me, but then again, I couldn't get the water stones to work well, so I might not be the best judge... but I really do like my setup convenience wise. No water, no mess, no clean-up - well, I guess I do wash my jeans after wiping the dust on them :)

  4. I think you're right about presure on water stones, when I started, I was puting way to much presure and now I forced my self to let the weight of the tool and the stone do the work... So far so good for me.
    I tryed the sand paper and it worked real good but not having the space(10 x 12 shop) I found it a problem with the plate glass and also found the paper to wear out fast!?!?
    But like you said, you use what work for you!
    Thanks for your blog.
    P.s. if you want to get reed of your water stones, keep me in touch!!

  5. Dan: Very nice. I don't own any Planes yet as You know in some of my Latest Comments.

    I do Sharpen Knives thou, my Pocket Knives and kitchen knives. And I use 3 Stones, Course, medium and Fine or what I call my Buffer.

    If the blade isn't the bevel I like, I send it through my Course and on through the other grits.

    If it needs just an Edge, It goes to my Med then my Fine/Buffer. If I need it Scary Sharp, then the last Step is threw my Dimond or Ceramtic Sharpner "The one on the Can Opener" to achieve the rest lol


  6. David - Thanks, that confirms what I was thinking - too much pressure. When (if) I give them another try I will keep that in mind. As far as the paper wear issue, so brands seem to last much longer than others - the sheets I have on there now are about done, but they have lasted at least 6 months, maybe closer to a year. I brush them off frequently as I use them - which I think helps.

    Handi - are they water stones or oil stones? How do you keep them flat?

  7. Hi Dan, do you keeep the paper dry or you put some lubricant(H2O, WD40...) and wich brand you think work best!

  8. David - I always use it dry. I suppose you could use lubricant, but I don't really know if that would improve it or not. Hmm. It might be time for some experimentation...

  9. Dan: I don't know what kind of Stones they are... My Buffer as i call it, I apply 3n1 oil on it, the same with the other Stones..

    It's a Stone that you Flip... It's one of them Elcheapos you can buy at a Flea market.

    I don't worry bout Being Flat cause I only Sharpen curved blades with it, Knives and the likes, So It don't need to be flat cause I have a Bevel on both sides.

    It's also how I curve my Hands when I put it on the Stone.

  10. I have this small skinning axe I got from a friend a few years back and thought it was nice and sharp! Finished it on a trusty arc tube filament. I saw this page and just for something to do, I ran the blade up 400/500 600/800 1000/1200 and then 1500/2000 3M wet/dry paper. I used the glass from an old copier machine I had laying in the garage. Axe blades are tricky for me so I took my time lining up how to go but once I did, less than ten minutes and WOW! This little sucker cant lay around the shop just anywhere anymore! It's freakin dangerous and the bevel shines like a mirror. If you picked this thing up and brushed your thumb at it, you'd be bleeding guaranteed. Now what can I go find to skin with this darn thing? Amazing process

  11. Mike - Yes, the process is aptly named - Scary Sharp indeed! So far the only drawback I have found is being too lazy to change the sheets when they wear out. Thanks for commenting.

  12. Great stuff! I independently thought up this idea over 30 years ago. Never knew that many others had the same idea. I do use automotive wet or dry paper up to 1000 grit and better. Sometimes 2000. If the blade can dry shave the hair on my arm, I'm done. And that's kinda scary!

  13. I have used waterstones for about a year now, and - as a result of this blog - decided to try scary-sharp for flattening and mirroring the back of new chisels (waterstones left them "cloudy-mirrored"). I ordered 4 grits of paper from toolsForWorkingWood (self-adhesive, nice), and set to work. The result was mirrored surfaces, and - without a doubt - the scariest, sharpest edge I've seen yet. I wasn't expecting this. One swipe of the blade (my wife hates this) sheared hair off my arm perfectly. And, no waterstone mess to clean up. Thanks Dan!!!

  14. The dedicated sharpening station is gorgeous!

    I just invested in my 1st decent Japanese chef knife, so doing some reading on the maintenance methods available.

    I don't mind the waterstones. But knowing that it is necessary to flatten them regularly is putting me off. Seems like an additional PITA step that will set me up for massive procrastination...

    Have you heard any feedback back on 3M abrasive film? How long would they last? Any insights would be appreciated thanks!

  15. Anonymous (1) - Yes, apparently the concept has been around for a long while, which makes sense because it is so dang simple! Thanks for commenting.

    Anonymous (2) - You are welcome! It is such a joy to work with sharp (really sharp) tools. I'm glad the post was useful!

    Coffeenciggy - Thanks!

    I don't know anything about 3M abrasive film; sorry. Once your knife is sharp, it will only need honing to keep the edge which would be on the highest grit, and these tend to last the longest...

    I could be wrong, but if I was going to be sharpening knives often, I think I would mount the abrasive on top of a thicker block (granite maybe?) so I could sharpen with more room for fingers and handle. Or you might consider making a strop. Also, and again I could be wrong, I think some chef's knives are meant to have micro serrations to "saw", which I think are most often created with a steel "sharpening" rod, which in my limited experience cannot truly sharpen a dull blade, but does fine with a sharp one...

  16. Dan. Just got reinterested in woodwork...finally have the time. I kept hearing about Scary Sharp. Thanks for the info i will give a go. My question is if you have ever tried this on knives

  17. Just out of college, and beginning to collect my own hand-tools - I'm glad I ran across this. I have a few hand-tools that have been passed down - among them a Stanley No. 4 Jack-plane... which became pitted with rust while it was in the hands of another family member. Do you know if this method can be used to re-surface the bottom of a jack-plane?

    I guess what I need now is to find some plate-glass, and drop by auto-zone to get some finer grits of sand-paper. I have a single chisel (new, but needs sharpening) that I'm using for a project until my income grows - I think I'll give it the honor of being the inaugural patient for this new treatment. Thanks Dan!

    1. Nicman - You're welcome! I'm glad you are enjoying the blog - sorry it's in one of its dormant stages just now - should turn around again soon. Scary sharp works great for resurfacing the soles of planes - as long as you have enough surface to work with. Also, you don't need plate glass, although it does work great. My school set-up, which is in the blog somewhere (try searching "Sharpening"), uses granite tiles from the Borg, and it works fine. A sharpening guide can be a big help, but eventually you won't need it, so I recommend the cheap side clamping ones if you go that route.

    2. I tried Scary Sharp a few years ago and have to admit that I was skeptical at first. Before that, I also bought brand name water stones and diamond stones looking for the "Holy Grail" of sharpening systems. They worked OK, but the process seemed slow and messy, not to mention expensive. Once I tried Scary Sharp (on a Lie-Nielsen #4 1/2 plane), I was blown away with great results. The article I had said to buy a cheap 50x magnifier (from Radio Shack) to look at blade edge. I couldn't believe the difference between the two methods! It opened up a whole new world of hand tool woodworking for me and have since used the method on all of my plane irons and chisels. Great idea on dedicated sharpening station. I'm pressed for space but I'm going to apply that idea to a piece of plywood that I can hang on the wall when not needed, and clamp to my workbench when needed. Thanks.

  18. Great post, Dan. I've used both stones and paper, with more or less the same end results. I do wet sand, always. The paper lasts much longer, when used wet. The slurry also helps put a fine edge on the steel. When flattening planes, it is important to file the sole in a figure eight pattern. This helps keep the plane flat and square and will help prevent removing more metal from one side than another. Enjoy!

    1. Thanks for commenting! I have used it wet, but mostly just use it dry. Maybe I'll revisit that...


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