The Bleeding Edge

[Oldtoolsniper]

  On 1/31/2016 at 6:29 PM, Art said:

Sniper,

How about a name to go with "Beaver from Iowa" Avatar.

I know a few guys who do scissors. They go from shop to shop with a Wolf or even just a grinder with some aftermarket jig and that's all they do, run out of the back of a van usually. The Wolf works fine for most scissors, but then you get the occasional hairdresser oops, stylist from Rodeo Drive who just has to use $1000 scissors where $150 would do. The Wolf will not do these well, I have seen the results, or maybe it was the guy running it. I have found the Edge-Pro to do a good job on any of these things, even the uber expensive ones. I got my Edge-Pro back when he first marketed it and it has worked from kitchen to salon. It now stays setup for scissors. Till you get used to the way to do scissors, you will bleed over everything, those thin little cuts hurt after a while. On the really good scissors (the $100-$200 kind not the $1000, as that's just too much for anybody to pay for scissors) you can get an 80° or 90° edge sharp enough to cut skin on touch. I really didn't believe that till I did it, and I bled. I have a roll of alligator skin tape that IF I remember to put it on, helps to keep me from getting cut-up.

Art

I'm pretty shocked that scissors could get that sharp and it's been pretty easy. Granted I just do it for my friends and family but I won't ever use dull ones again. I sharpen my utility blades before I use them so I'm a little on the odd side in that respect. I learned to sharpen because of handplanes and my enjoyment of woodworking. I just could not figure out how to make a handplanes work. There are so many of them out there so they must work or it was one huge scam pulled on everyone that bought the millions of them out there. When I learned I didn't know what sharp was, I started down the path of learning. Funny thing about learning how to sharpen is how much stuff everyone has for you to do. I've learned to say no, I don't want a second career. I just want sharp tools.

Roy

[Art]

Hi Roy,

Planes are a whole different ball of sharpening. It is really necessary to understand the geometry of the plane bed, the blade, and the cap iron to get it sharpened properly. A lot of planes really need a little back angle (on the back of the blade) to function properly. I like to get the whole plane when someone wants one sharpened, not just the blade.

Scrapers are another animal too, too many guys have planes up the wazoo but not a scraper in the house. A good scraper like a Stanley 80 (properly sharpened and hooked of course) can save a ton of planing (with risk of tearout) and sanding.

It is hard to refuse when someone brings you a sorry tool that just needs a little TLC.

Art

[MikeG]

Art,

When I first started leatherwork, I attended a class where I was totally embarrassed that my best sharpening efforts were very poor. I quickly learned that leather tools need to be surgically sharp. I now sharpen blades on glass with wet/dry paper. Once my blades are sharp, I keep them honed, and I'm one of the guys that hones my razor knifes and scalpel blades. I'm of the belief that keeping a properly sharpened blade honed/polished is all that is needed and that resharpening is almost never required unless it is damaged or nicked. I would like your take on that.

Another question -- head knives. Is there any way to set up a jig for sharpening a curved blade? I have one that has a true circular blade and have thought of drilling a hole at the radius & using a bolt to maintain a constant angle for sharpening -- I just haven't built up the courage to drill a hole in a really nice head knife. My others are not truly round or the curve is too large to do this. So what is the best way to get a perfect uniform angle?

I am looking forward to this forum!

Thanks,

Mike

[LumpenDoodle2]

My question is in the same vein. I bought a French pattern head knife last year from fleabay. It was quite 'tired and emotional' and really needed a lot of work to get it to the point of being useable.

I admit to having minimal knowledge on sharpening knives, but it is improving. My one thing though, is getting an equal sharpness over the whole of the head knife. It's at the point now where it will cut through 4mm with ease, in fact a couple of times I've thought it was making heavy weather of it, only to discover the knife cutting deaply through my mat under the the leather.

As I've said though, not all of this knife is equal in sharpness, and I just can't get the technique quite right.

[Art]

Proper honing should work to keep the edge sharp for quite a while, but eventually, and this depends on the hardness of the steel, the edge angle will tend to increase as the edge is replaced by the steel underneath. When we hone, we do remove metal and actually create a new edge, so the included angle increases unless we actually hone the whole primary bevel and move that back. Moving the primary bevel back is actually sharpening. Every blade that I do gets a new primary and secondary. On head knives, we do a flat primary only, it just works better that way as the user can find a flat primary easier than a secondary. If you ask real nice, I'll put a secondary bevel on a head knife, but I don't recommend it as it is very hard to find that secondary when hand sharpening.

Head knives can be sharpened with a jig, but I do them freehand on a 6x48 laid down flat if it is a real basket case, or on a Makita 9820 rotary flat waterstone or a diamond rotary lap.

To make a jig for head knives (which are practically round), make a base that will present the knife at the desired angle to the abrasive. Put a pin in it that a top piece will rotate upon. You can make the top piece of delrin with holes in the bottom for the approximate radius that you want. Make a cutout in the top of the delrin piece to let the handle stick out and let the knife lay flat. Countersink and glue a couple of Neodymium magnets (eBay) to hold the wings of the blade. You'll have to work it out from there.

A Pecard's or Vaseline treated strop with .5 micron green compound (we however use 3 micron diamond paste on our rotary strops, and .5 compound on our felt wheels) will keep a knife very sharp between honing sessions.

Of course, everything can be done with stone grades extra coarse to extra fine and a strop and some compound.

Art

[Art]

Doodler,

It is much easier to sharpen any curved blade on a moving stone as you can pay more attention to your angle. Another trick you learn is that the curved portion of the blade (called the belly) can be manipulated to the proper angle by raising the opposite end of the blade. The French Head Knife (we call them a linoleum knife over here) cuts mostly on the belly, so learning to sharpen that part and presenting that part to the stone at the desired angle is most important. The other important thing is to use the same angle as you go up through the grits.

Unfortunately this is all practice, but keep a felt tip or magic marker handy and mark your edges before you stone to keep a check on doing it right. Also get a 10x glass (loupe), even a cheap one will show you any inconsistencies. Buy the magic marker before the loupe.

Art

[Pablo27]

This is such a great thread, a lot of information and experience in a couple of pages. Thanks so much Art for sharing so much with us that need it. What is your opinion of Japanese Water stones? Are you supposed to use them like regular stones with a back and forth, or circular motion or just a pulling motion like a strop? Thanks again for taking the time to help us here.

Paul

[Art]

Hi Paul,

The Japanese water stones started showing up 35 or so years ago. Before that we pretty much had Arkansas and Carborundum. At first, it was mystical hype and then we figured out you really could get a better edge with them. The downside was they cost an arm and a leg (but then a good black Arkansas wasn't cheap), and they would wear quickly, often in the form of a trough in the middle of the stone. Not a problem, DMT came out with the diamond lap, and troughs were eliminated in all stones throughout the land. They work very well, and you learn to use the stone in an allover fashion to minimize the grooving, still, they must be dressed frequently. Over time, most stones will wear, it is the nature of the beast to be friable so as to expose new cutting surfaces. The water stones seem to wear faster than others. Shortly thereafter came DMT with diamond stones which are still the best in my estimation. As far as pulling, pushing, or sawing, I don't think it matters. I'm sure someone can argue to the contrary, but I just haven't seen it. We pretty much use Diamond stones for most applications, both wet and dry, power and hand. The only waterstones we use are on the Makita 9820 grinders, and the occasional use of a Silicone Carbide stone on the Makita for carbide tools. The general tool sharpening theory is that the grind marks (be they ever so miniscule) should run in the direction of cutting. The old timers (oops, I think I are one) would tell us to sharpen a tool like you use it.

There is a new stone that is gaining popularity, the Shapton Ceramic Water Stone. They are a tad expensive, but so are Diamond Stones. Use them like a Japanese water stone, but they hold up better and are supposed to make superior edges. Ok...till the next great thing comes along.

Art

[LumpenDoodle2]

Many thanks for the reply, I do like the idea of using a felt tip pen. I did once look at the blade with a 20x loupe, made the edge look like the Pyrenees.. Scary.......

[Colt W Knight]

I grew up using a double sided Norton sharpening stone with incredible success. Then my dad gave me an burned out ceramic light bulb from a huge light on a dragline. After sharpening with the Norton stone, I could polish up the edge using that light bulb like a steel and my knives became sharper than I've ever experienced. These days I have an expensive set of DMT diasharp diamond stone from extra coarse to extra fine. These are excellent sharpening devices, but the greatest advantage to me is I use them to level and dress guitar frets. They make quick work of that.

I think my greatest evolution in sharpening came when my uncle explained how the metal of the edge tip looked microscopically. Sharpening creates a super thin sliver or feather of metal at the point. Stropping keeps that feather straight and as you use the edge it begins to roll over and makes the edge dull. If you frequently dress that edge with a steel or strop, you can keep the edge sharp longer without a need to reshapen on a stone.

Ideally, you can sharpen that feather into the edge and polish it away for the most superior cutting edge.