Sharpening with Sandpaper and Glass....

Marion David Poff

Marion David Poff

Joined
Oct 8, 1998
Messages
5,403

I am working on a project.

I am going to buy a piece of
glass, .25" thick by 1" wide
by 9-12" long.

Then I am going to buy
different sandpaper grits
and spray adhesive to attach
them to the glass.

Glass provides true surface.
Sandpaper provides
consistent grit. Add Loupe
and I may just be able to
figure out this free hand
sharpening thing.

Cool thing is, I can get
diamond abrasives from 3M in
sheets......

------------------
Thank you,
Marion David Poff aka Eye, Cd'A ID, USA mdpoff@hotmail.com

Talonite Information and Resource Page, including other cobalt materials.

"We will either find a way, or make one." Hannibal, 210 B.C.
 
I guess the only problem I foresee is the depth of the grit on the paper. How long before you are through the grit and into the paper. On stones the grit is all the way through. I guess on better quality papers the grit adhesion should be good but it still may not take very long for you to rub through. Well make sure to post your results.
smile.gif



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ALex

http://home.att.net./~a.boriqua

[This message has been edited by Boriqua (edited 03-05-2000).]
 
Marion,
I think the most important thing on your list is the LOUPE!! No matter what method or materials you use to sharpen, I feel the MOST important thing is being able to SEE the edge. In many other posts I've mentioned the microscope I use for sharpening. It's not anything special or expensive. It came from Edmund Scientific and I bought it at a yard sale. I cant say what the magnification is but the "wire edge" or burr on a blade, looks BIG
smile.gif
I made a little fixture for it that keeps the blade in the center of the focal area allowing quick inspection of the entire blade edge. After getting used to what a SHARP edge LOOKS like, I no longer need to shave hair off my arm or cut anything. Once the edge has the proper look and the angle is consistant along the entire edge, that's it! It's scary sharp!
I found this especially helpfull with sharpening Talonite. It never seems to feel sharp. It took more work to create the consistant angle and remove the wire edge than any other material I work with. For me, getting the edge even, consistant and sharp would have been a REAL pain without the microscope.
I'm interested in hearing your results.
Neil

------------------
Blackwood Knives
More knives in stock! New Talonite models soon!!
http://www.geocities.com/Eureka/Meeting/5520/index.html
 
Marion , I have used the sandpaper on glass
method to flaten and sharpen all sorts of things.It works great but is not very economical in the long run (for knife sharpening) because good wet\dry sand paper costs fifty cents a sheet for 400 to 800 grit and the higher you go the more it costs.But you mention 3M diamond sheets and
that is a new one on me.Would you please tell us more about these as I would be most
interested in getting my hands on some .And
thanks for the info.
 
I have used this method to sharpen wood working tools. It works very well. I would however get 3/8" glass as less may flex.

------------------
Roger Blake
 
MDP Great Lakes Orthodontic supply sells a kit for sanding orthodontic study models.Basically it comes with a 3/4"thick by 2and1/2"wide by 7" long lexan block for attaching the sandpaper 20 pieces cut to size of 3M wet or dry 400grit and 20 600grit all self adhesive.The price is somewhere around $20.I have used it as a fine stone and it works pretty good.Lately i've been finishing my knife edges on a DMT black extra coarse stone and leaving them that way.Man I love a raggedy-grippy knife edge.
troy

[This message has been edited by Ben E Hana (edited 03-05-2000).]
 
Why such a narrow piece of glass?
I use a similar method to sharpen leather knives but just wet a full sheet and slap it on the glass. Use a lot of water and the sheet sticks to the glass well enough. There is no need to glue it.
 
Even if you don't end up ONLY using the technique it seems like a reasonable way to at least rough sharpen, which is where most of the wear takes place. Ceramics don't seem to do as well as other mediums in the coarse grits as the medium although hard doesn't seem have a lot of 'tooth'. Diamond seems work well but it's pricey and the stones don't seem to last as long as one would expect for the price. The aluminum oxide or silicon carbide stones work well but they dish and need to be flattened. Whatever technique or combination of techniques if one has a good, flat coarse stone one can flatten other traditional stones as required.
 
Let us know where you get the 3M diamond paper and how much it costs. I'd like to try it on some worn diamond plates I've got.

I'd probably go 2" wide on the glass--I've got a 2" wide 12" long diamond plate that I really like. You run a risk of tipping your blade a little as you hone and cutting into the edge of your paper. Having a wider plate should reduce this tendancy. You might even want your plate slightly wider than your abrasive strip.
 

"and I may just be able to
figure out this free hand
sharpening thing."

Just my opinion, but it seems to me most of the people who can't get the hang of free hand sharpening, are either in just too big of a hurry, or not starting with a coarse enough grit. In todays world of microwaves and disposable razors, sharpening a dull blade takes a "long" time. Holding the angle steady is maybe part of it, but even if you change angles with every stroke, you will eventually get your wire edge burr.
Its easy to read on the forums how a blade is quickly brought to "hair popping" sharpness, but there are lots of variables, and lots of ideas of what hair popping sharpness is.

Free handing is not the fastest way to sharpen a blade. Like a lot of you other kifeknutts, over the years, different stones and "sharpening systems" multiply just like the knifes do.

When i am in a hurry, or just not in the mood to free hand, I can take a very dull blade and fire up my grinder with a silca carbide wheel on it, and make a very nice edge litterally in a matter of minutes. Then a swipe or two on the buffing wheel (strop) and its done, and very nicely sharp.

On the other hand, when I am in need of some "therapy", I enjoy setting down in front of the hones, and take pride in doing it the old fashened way. But to start with the coarse stone, and work one side down to a burr, then the other side, then switch to the medium stone, and work one side to a burr, then the other, then stitch to the fine stone and work one side down to the burr, then the other, just takes time. Maybe ten minutes, maybe thirty minutes, or even a little more. Lots of factors come into play.

I know I may have gotten a little of the intended post, but just had to throw my thoughts out. (I better not be throwing too many of my thoughts out, I don't have that many to spare!)
smile.gif
 
I heard about this method from a woodworking article.

beam, Thanks for the tip on the thicker glass.

TomW, I am going with the narrower width to accomodate blades with lots of curve.

Neil, I just bought my loupe and it is teaching me already.

SD, Look 3M up on the web, call a local rep and they will direct you to a local dealer, or contact a big industrial dealer, I am to understand that they are pretty available on the industrial side.

johno, good synopsis.

kzn, I like your thoughts, I am going at this method to deal with my larger knives, like you said, one accumulates sharpening gadgets, but none of mine to date does big knives well. I am pretty good with a coarse stone free hand, but once I try to go finer, I screw up.

I like the idea of being able to choose the abrasive level exactly, to fine tune a method that works for me.

------------------
Thank you,
Marion David Poff aka Eye, Cd'A ID, USA mdpoff@hotmail.com

Talonite Information and Resource Page, including other cobalt materials.

"We will either find a way, or make one." Hannibal, 210 B.C.
 
David,

Have you seen this
cool.gif
?

------------------
Clay

Don't worry that the world might end tomorrow....in Australia it's tomorrow already.
 
David , to what type of material does 3M
attach the diamonds ? Is it flexable ? Does
it come in regular sandpaper sizes ? It is
just that I have never seen or heard of such
stuff and am not likely to in this town of
50k folks.Thanks !
 
Going narrow to accomodate curved blades is the wrong approach. If your curve is convex you don't need any accomodation. If you have a recurve you are sure to be cutting into the edge of your paper, 1" wide or not. What you should do for recurved blades is apply your paper to the outside of a cylinder. A good cylinder would be a piece of 1.25" diameter aluminum tubing.

BTW, there is nothing magic about using glass to mount your paper. It is nice and smooth, but so is aluminum or even the hardboard that they use to make clip boards.
 
Clay's link was interesting.
This doesn't involve glass, but for what it's worth;
The late Mel Sorg (MadPoet Custom Knives) made a set of D2(same steel as planer blades) knives for me bfore he died. He was a former pro meat cutter and avid outdoorsman. He sharpened his knives in the field with a piece of 1000 grit emory paper over a piece of smooth leather which he carried in his wallet at all times. He told me he back-stroked or stropped his blades lightly with this setup. I can give testimony to the sharpness of his blades.
I've never had any difficulty getting a good edge freehand with stones either, but if I use my good stones (instead of my #204) I use them DRY and wipe them off every few licks with a damp rag. I have come to think (right or wrong) that using oil builds up a paste on the surface of the stone that is the equivelant of plowing a microscopic pile of gravel with your edge.
I have been disputed on this here before but you can do it your way- and I'll keep doing what works for me.
 
220 grit sandpaper turns to 1200 grit faster than you might think.... If you don't use a stone evenly, all over the whole surface, it doesn't wear evenly and it gets dished. If you don't use sandpaper evenly it turns to 1200 grit where you're using it and stays 220 grit where you aren't. BTW, the same applies to diamond hones ... it just takes a lot longer.

-Cougar :{)
 
Sounds interesting... I'll look forward to hearing how it works out! I like my Spyderco stones, almost diamond hard and seem to last forever!
I have used glass though, did you know you can use the top of a car window to "steel" up a knife? It works great for straightening the edge!
 
I believe that the Japan Woodworker sells 3M diamond paper, and a myriad of other sharpening stuff. It is all in their print catalog, though and not at their web page. You can go there to order a catalog though.
http://www.japanwoodworker.com/

It is a pricey catalog to order from, but everything they sell is top notch.


------------------
Paul Davidson

Them:"What's that clipped to your pocket, a beeper?"
Me:"Uuh....yeah, something like that."
 
You can get very fine grades of wet dry, 1000 to 2000, paper at an automotive supply store such as PepBoys.

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Roger Blake
 
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