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sharpness: or how sharp is too sharp?

3K views 7 replies 7 participants last post by  Lazy_K 
#1 ·
sharpness: or how sharp is too sharp?

Sharpening: gives me headaches just thinking about it!

Not because it is difficult! It is NOT! but it is the prime example of a place where every effort to "simplify" or make it easier has resulted in More confusion and More difficulty!

it started at least 150 years ago with the first Victorian era quick and easy sharpening jigs and guides. and has gone rapidly downhill.

Sharpening, you should do it once a day
for every tool you used that day. at the end of the day put them away sharp. if they dull up during the day, stop and sharpen them.

However it has come to my attention the some of y'all think that it requires at least a half an hours work to sharpen anything. But if that were the case then sharpening those 3 chisels and 4 handplanes you used today, (and the ax and the 2 knives) would take at least 5 hours!

I used to work with a person who was like that: I would spend about a minute during the day to re-sharpen a chisel. just a touch to keep it cutting well. He would never use his chisels because it took him so long to sharpen them.
when I asked him why he didn't just use his plane or his chisel on something he would talk about his elaborate "scary sharp" system (I had previously learned this system and dismissed it as being too elaborate and time consuming) and how long it took to get them perfect and how many hours he had spent making the backs perfect etc etc etc.

So I asked Why he did all of that. And he elaborated at length about all of the AMAZING things he could do with his tools so sharp! and I will grant you there are some amazing things you can do when your tools are that sharp

BUT:
90% (bogus off the cuff stat here) of the time you Don't Need to do those amazing things! You just need a little trim or smooth off. trim a peg, clean the corners out of a routed rebate.
And NOT using your chisels because you don't want to sharpen them is counter productive. Hell: spending 5 minutes with sandpaper instead of 1 minute with your hand plane or chisel is not a smart use of your time!

there are some questions I want you to ask yourself:
does it really need to be that sharp?
how Sharp is sharp enough?
if it takes that long to sharpen are you really doing it right?

Fer instance: Take your typical Drawknife, here is a tool that will definitely give you trouble if you oversharpen it! If you perfectly polish the flat face and hone the bevel to a mirror; when it cuts, it cuts so clean that there is a virtual vacuum created between the tool and the wood making it stick and drag horrifically. It also cannot follow the grain and may tend to go anywhere.
If instead you sharpen a Drawknife with your cheap hardware store 2 sided ALOX stone (use the "fine" side) it works like a dream, the cut faces are not perfect but I guarantee you'll find them good enough. And don't you usually switch to a Spokeshave to finish with?

Your typical ALOX stone can give you an edge that is fine enough to shave with. you can test it on your arm hairs (if you have any). (not a recommended technique)
If you want a little sharper a medium Arkansas stone Of a fine Belgian stone will do the trick with just a couple of licks.

When you need to grind/regrind the bevel use a wheel with no smaller than an 8" diameter stone. 6 or 4" stones make a hollow that is too deep.

My process is simple:
to regrind the hollow I mark/color the bevel with a "magic marker". using my hand as a guide grip the blade so that only the center of the marked bevel touches the grinder. turn on the grinder, grind, check frequently to make sure you remain centered on the bevel, do not grind all of the way to the edge or the heel (unless you are fixing a damaged blade).
NO elaborate Jigs or tooling!!!!
check for square across the blade, (and you can check the bevel angle with an angle gauge if you want to. it's really not necessary.)
Take your ALOX or Carborundum stone, oil it. put the bevel down on it, rock it until you can feel where both the tip and the heel of the bevel are touching. move all over the stone face to hone, just a little! it doesn't take a lot to take the grinder marks off from the edge. touch the face on the stone just a little to take the wire off.
AAAAAAnd I'm done total elapsed time from deciding to sharpen to finish is less than 5 minutes.
be well
K
 
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#4 ·
Lazy k, I'm in agreement with your thoughts. I learned how to sharpen my chisels and plane irons more than 40 years ago when I apprenticed in a mill/cabinet shop. If my foreman saw me taking more than a couple minutes to hone a tool he would let me know about real quick. A couple minutes on a quality Arkansas stone was all it took to put an arm shaving edge on a chisel or plane iron.
 
#7 ·
Picklehead - - I wonder what changed for Paul - because I was watching, and his video on how to sharpen was in the side bar… using 3 stones, and finishing with a leather strop with Chromium oxide paste…

He mentioned in your video how the higher than 250 planed surface is too smooth to hold finish, so he has to rough it up anyway…
But his sharpening method he teaches is to go to high grits.. Then video below is OLDER than the 250 grit discussion… it wasn't so clear WHY he changed.

 
#8 ·
Don W et al
the Angle of the bevel is not an exact thing, Oh, if you studied it really well you could probably find that one angle works better for oak and another angle works better for pine etc.
but the grind on a bench chisel wants to be somewhere between 25 and 35 degrees, that is a huge range! generally: softer woods cut better with a shallower angle, harder woods need a steeper angle to keep the edge from shattering.
but a precise angle isn't necessary. something close to 30 degrees works well for everything if it's sharp.
Spending a lot of time sharpening is time not getting work done.
$80 jigs are not needed. I'm sure the makers of the jigs don't want me saying that. ;)

K
 
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