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How sharp is sharp enough??

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Forum topic by JJackson posted 04-07-2008 10:31 PM 2229 views 0 times favorited 14 replies Add to Favorites Watch
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JJackson

104 posts in 4082 days


04-07-2008 10:31 PM

Evening All,

I was wondering, how sharp is sharp enough for chisels and plane blades?? My current process for chisels and plane blades is to flatten the backs to 2000 grit, then create a hollow bevel on the front, and then sharpen the bevel to a mirror polish of 2000 grit on my Worksharp. I then take the chisel or plane blade to my bench grinder and buff the bevel with a cloth wheel and polish. I can shave hair on my arm very easy. But is this sharp enough for planing and chopping dovetails?? I have an 4000 grit waterstone and an 8000 grit waterstone but I get so tired of the mess and having to flatten the waterstones. What do you all think? Is 2000 grit sharp enough or is there a benefit to moving to a higher grit/waterstone?

Thanks,

Jeff

-- Jeff, Indiana


14 replies so far

View GaryK's profile

GaryK

10262 posts in 3988 days


#1 posted 04-07-2008 11:17 PM

Shaving the hair on my is the test I use. Can’t get much sharper.

-- Gary - Never pass up the opportunity to make a mistake look like you planned it that way - Tyler, TX

View Al Navas's profile

Al Navas

305 posts in 3875 days


#2 posted 04-07-2008 11:23 PM

lol – Gary, WHAT do you shave??? ;-)

Jeff, the shave test is usually a pretty good indicator. I think what you are doing IS good enough. I am sure you will get many other opinions from hand tool folks.

I always test sharpness by (carefully!) shaving some of the hair on my forearm, in one pass.

-- Al Navas, Country Club, MO, http://sandal-woodsblog.com

View Scott Bryan's profile

Scott Bryan

27250 posts in 3821 days


#3 posted 04-07-2008 11:26 PM

If you can shave with it then it is ready to use.

-- Challenges are what make life interesting; overcoming them is what makes life meaningful- Joshua Marine

View Tony's profile

Tony

986 posts in 4030 days


#4 posted 04-07-2008 11:29 PM

I usually take a piece of paper held in one hand and try to cut it upwards with a chisel or plane blade. If the paper cuts cleanly, without any sign tearing or without a sheer cutting action of the blade, then I deem it sharp enough.

A lot depends on the quality of the steel in the blade, sometimes it is not worth sharpening too much, if the edge does not hold well.. At the the end of the day, if you are happy with the quality of the cut then its sharp enough. Don’t forget the angle of the blade (Chislels) should be shallower for soft woods (20°) and steeper for hard woods (30°), hence the compromise of 25° on most blades. This will also affect the cutting perfomance.

I use a Tormek for my sharpening process, so I cannot comment on the grit, but I have never had sharper blades, than I have now.

-- Tony - All things are possible, just some things are more difficult than others! - SKYPE: Heron2005 (http://www.poydatjatuolit.fi)

View Bob #2's profile

Bob #2

3809 posts in 4021 days


#5 posted 04-08-2008 12:54 AM

I toss a silk handkerchief in the air and let it land on my blade. If I don’t get two pieces I kick it up a notch.

Honest!

Bob

-- A mind, like a home, is furnished by its owner

View jcees's profile

jcees

1058 posts in 3798 days


#6 posted 04-08-2008 02:06 AM

Bob #2 you’ve been watching The Bodyguard again, haven’t you?

JJackson, 2000 grit is plenty sharp for working wood. Heck, it’s gonna get dull on you anyway. Especially if you use it! Skip the buffer next time too. Act like you don’t even have one and put the blade to work after the 2000 grit. Note how long it takes before the edge begins to break down. When you notice that, whet the edge and go back to work. Again, Skip the buffer, you might be ruining your work with the WorkSharp. Besides, buffers and edge tools are a recipe for disaster. And I’m not just talking about ruining your edge either.

Learning how to sharpen quickly by hand was an epiphany for me. I am now convinced that I could live out the rest of my woodworking days with a large 220 grit Norton diamond stone, and a large white washita and an endless supply of WD40. Of course I’d miss my large hard Arkansas and the strop with polishing compound… but not too much. The slurry on the washita puts an adequate polish on the bevel and that’s fine for 99.44% of what I do. Hope this helps.

always,
J.C.

-- When one tugs at a single thing in nature, he finds it attached to the rest of the world. -- John Muir

View Alin Dobra's profile

Alin Dobra

351 posts in 3887 days


#7 posted 04-08-2008 02:38 AM

Jeff,

Sharpening the tool too much makes the edge too fragile. I agree with the other posters that you are sharpening enough (or on the too much side). The most important thing is to touch up the tools while you work. No edge will stay too sharp when you hit the chisel with a mallet. The plane iron should stay sharp for a while though.

Now, stop sharpening and start cutting some dovetails.

Alin

-- -- Alin Dobra, Gainesville, Florida

View trifern's profile

trifern

8135 posts in 3767 days


#8 posted 04-08-2008 02:50 AM

Sharp enough to shave the hair off of a frog’s back.

-- My favorite piece is my last one, my best piece is my next one.

View Doug S.'s profile

Doug S.

295 posts in 3707 days


#9 posted 04-10-2008 03:28 AM

I used to shave hair to test, but the cat refused to hold still for it any longer. Cutting paper is just as good to test and doesn’t bite and claw.:-)

-- Use the fence Luke

View Roper's profile

Roper

1389 posts in 3712 days


#10 posted 04-10-2008 04:46 AM

hey jeff, if i am cutting compound dovetails i need my chisels really sharp so i take them all the way to 8000 grit,that way i don’t get a lot of tearout.also if you have a really nasty curly maple that just want work i take my plane blade to 15000 grit. it works well for me after that.plus remember to strop often.

-- Roper - Master of sawdust- www.roperwoodturning.com

View ChicoWoodnut's profile

ChicoWoodnut

904 posts in 3815 days


#11 posted 04-10-2008 05:39 AM

I suppose for me it depends on wether I’m choppin or parrin.

-- Scott - Chico California http://chicowoodnut.home.comcast.net

View Thos. Angle's profile

Thos. Angle

4444 posts in 3962 days


#12 posted 04-10-2008 02:24 PM

Sharpen until it cuts the way you want it to. If it doesn’t suit you, sharpen some more until it does.

-- Thos. Angle, Jordan Valley, Oregon

View Woodshopfreak's profile

Woodshopfreak

389 posts in 3742 days


#13 posted 04-18-2008 06:21 AM

I need to get some higher grit paper so that it will shave the hair off my arms as well. I have the same problem, sharpening my chisles.

-- Tyler, Illinois

View Derek Cohen's profile

Derek Cohen

373 posts in 3968 days


#14 posted 04-18-2008 04:06 PM

The arm hair “test” proves very little. That does not mean that I don’t do it as well, but it is not a decent test of “sharp”.

A better test is to pare endgrain pine. Soft wood is always more of a challenge to cut cleanly (without breakout) than hardwood.

As an aside, I prefer the term “smooth” to “sharp” – because that is what sharp really is … the smoothest edge possible.

Regards from Perth

Derek

-- Buildiing furniture, and reviewing and building tools at http://www.inthewoodshop.com

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