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Chisel sharpness vs. wood type

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Forum topic by drpdrp posted 12-30-2013 01:36 AM 1306 views 0 times favorited 37 replies Add to Favorites Watch
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drpdrp

150 posts in 799 days


12-30-2013 01:36 AM

Not sure if this is in the right spot so forgive me.

Oh also I am really ignorant so forgive me for that too.

I’ve yet to meaningfully sharpen anything. I used a regular grinding wheel with the stone that came with it (30ish dollar HFT model) to put an edge on two cheap HFT chisels that I was using to chisel some weird glue off of concrete. I was able to take them from mangled by chiseling stone to sharp enough to hurt yourself…

I then, much later, tried to make one of those chisels nice(r?) using one of those four sided diamond blocks (again from HFT) to no real result.

I watch lots of videos on youtube and they often conflict one another and pretty much all start by saying “people think sharpening is complicated but it is really simple” and then proceed to outline the 500 steps they use that other people don’t and that require 8 items I don’t own.

Then I found a video from a guy who… and I am going to feel horrible if he is a user here… I’d seen videos of before and thought, “this guy has got to be doing cocaine” where he sharpened a chisel using his belt sander with 120grit paper.

Well, sezee I, I’ve got one of those (prolly the same HFT model) and so I took the other chisel I’d abused and gave it a turn. It was sharper… looked okay? I tested it on a bit of pine 2×4 that was nearby… reminded me vaguely of what it felt like new… And then I took it to a piece of ash I am going to turn into an english longbow… and it proceeded to gouge and tear and not really shave or slice.

So, all things being equal and my skill level being where it is… Is this guy totally nuts? Could I just up to a 220belt and get a decent result? Is it just a case that harder wood requires sharper tools?

I am sitting on an HFT gift certificate and was thinking of getting the wet dry sharpener grinder- but another guy who’s videos I’ve watched (and did not appear to be a crazy drug addict) said he doesn’t think you should sharpen on a wheel because it changes the blah blah blah insert complicated stuff here.

Thoughts?


37 replies so far

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Smitty_Cabinetshop

10381 posts in 1371 days


#1 posted 12-30-2013 01:48 AM

Man, drpdrp, you’ve touched on a bunch of stuff here. So much that I’m not exactly sure what the question is, except ‘how do I get a chisel sharp really?’

One thing is for sure. You won’t know what sharp is until you have a sharp tool in your hand. And although it sounds like you’ve gotten close, the time hasn’t come yet. This part of your post is most interesting to me (because it’s the sharpening system I use): using one of those four sided diamond blocks (again from HFT) to no real result.

Biggest part of any sharpening system is progressing from rough to fine, each time ‘raising the burr’ before moving on. If you’re not sure what a burr is, you’ve likely not worked with the grit you’re on long enough. Will a belt sander do the job? As opposed to a grinding wheel, to get the primary bevel in line and uniform, yes. To pare end grain? Not likely.

So where to go from here?

Consider researching ‘Scary Sharp,’ as many have luck getting good edges with that method. It’s also a cheap place to start the journey. From there you’ll likely move to your ‘final’ solution, either Nortons or oilstones or DMTs or etc. etc. But there really is a common (and simple) approach. Flatten the back of the iron. Create a uniform, consistent primary bevel. Raise a burr. Drop to a finer grit, raise a burr. Repeat until mirror finish. Then cut wood.

Long answer, many more LJs have expertise way beyond me and can add to / correct what I’ve provided. Hope it helps.

-- Don't anthropomorphize your handplanes. They hate it when you do that. -- OldTools Archive

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Loren

7826 posts in 2401 days


#2 posted 12-30-2013 02:01 AM

Some of those guys showing how to sharpen on a belt
sander don’t do fine woodworking I’ll bet. For rough
carpentry a chisel can be honed on a cinder block in
a pinch, but it won’t be nearly sharp enough or with
a clean enough edge to pare joints for furniture work.

I’ve decided it’s not worth sharpening mortise chisels
above my fine diamond stone… they get blunted
right quick from the heavy pounding anyway so a
fine polished edge is wasted on them. For a paring
chisel used on end grain, like a tenon shoulder,
you’ll get the smoothest and most predictable
cutting performance taking both sides of the bevel
to a mirror polish.

In practice most of us probably chop and pare with the
same set of chisels. I’m not saying this is the best
practice, but I do it and I have a lot of chisels and
could designate some for paring only if I wanted to -
the edges on those chisels would hold up a lot better
if I did.

It’s a thing to grasp that tools like grinders and belt
sanders are usually most useful for establishing tool
geometry. With some tools geometry is all you
need (drill bits for example), but with others like
plane irons, you need the geometry plus honing/polishing
to get anywhere near a pleasant experience when
using a tool.

-- http://lawoodworking.com

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drpdrp

150 posts in 799 days


#3 posted 12-30-2013 02:02 AM

When I was using the 4 sided thing it was with the very damaged and not yet repaired concrete used one… so maybe now that I’ve cleaned it up with the belt sander I can get the 4 sided to do something meaningful.

Is it a truism that harder wood requires sharper chisels?

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Loren

7826 posts in 2401 days


#4 posted 12-30-2013 02:10 AM

... yes and no. Cleanly paring something soft like end grain
pine takes a really sharp chisel because the wood crushes
into the fibers behind it. While you can power through
pine with a dull chisel, the result won’t be pretty and the
end grain fibers will break off. For mortises it is no big deal
because the end grain doesn’t show and the glue sticks
to the face grain, but for areas where it does show only
a very sharp tool delivers an excellent appearance in soft
wood.

In terms of chopping or paring into something hard,
the wood puts up a lot of resistance and the sharpness
helps cut the fibers (they don’t break off easily like
soft fibers do and the wood cells behind the fibers
being cut doesn’t give way as easily either). With a
reasonably sharp chisel, it is easier to do clean cuts in
the end grain of firm hardwoods. The finest paring
cuts in both hard and soft woods require a finely
polished chisel in my experience.

-- http://lawoodworking.com

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Biff

126 posts in 767 days


#5 posted 12-30-2013 02:15 AM

OP, I’ve been in the same boat as you! I struggled for years with jigs, etc. I found I got the best edges with sandpaper and a block of granite.

A few years back I fell into a Tormek system on trade. Since I had it, I decided to commit myself to learning it. The end result is lathe tools, knives and chisels that you can in fact, shave with.

Now I’m not saying the Tormek is the solution. I think the solution is to pick a sharpening system and commit to it. There are a lot of right ways to get any project done and sharpening is no different. No matter what method you use, it’s obvious that fine grit and cool grinding temperature are essential. As far as micro-bevels as such, few of us will probably ever notice the difference.

The other factor that should be mentioned is that some tools will just never take or hold an edge. My HF chisels just don’t ever get as sharp or stay sharp as do some of my Stanley, Sorby, etc. tools. Same holds with kitchen knives. There’s just nothing like a quality steel tool when it comes to taking an edge.

So there’s my .02 cents. Good luck in your quest!

-- Interested in Oregon property? Visit me at http://www.willamettepropertiesgroup.com

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drpdrp

150 posts in 799 days


#6 posted 12-30-2013 08:34 AM

What does micro bevel mean?

This is the thing I was thinking of getting:

http://www.harborfreight.com/8-inch-wet-6-inch-dry-grinder-35098.html

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shopdog

570 posts in 2238 days


#7 posted 12-30-2013 12:40 PM

Normally, I would be shocked that you used a wood chisel to get glue off of concrete :-), but I guess a harbor fright chisel would be my go to tool for that job. I always carry a beater chisel in my bag for jobs like that…and…
yes, a belt sander is what I use to sharpen my beater.
On the other hand, I sharpen my paring chisels using the scary sharp system, with a good honing guide (from Lee Valley). When I started accumulating tools many years ago, I bought some from Harbor fright, but when I learned more about tools, I stopped buying them from HF. Don’t bother getting the grinder.

That said…
a micro bevel is about 1° steeper than your normal bevel . I sharpen my paring chisels to a 25° bevel, and when they are as sharp as I can get them, I adjust my honing guide to 26°, and roll it over some 1000 grit sandpaper a half dozen times. That just sharpens about 1/16” from the cutting edge.
When I’m done, that chisel is scary sharp. I CAREFULLY test it on my arm hair. If I did it right, the hairs jump off my arm before the chisel even gets to them. That’s why it’s called scary sharp.

-- Steve-- http://www.urbanexteriors.biz

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Sandra

4985 posts in 828 days


#8 posted 12-30-2013 01:01 PM

Good morning,

Kudos to you for putting yourself out there to learn. I was in the exact same spot as you 18 months ago. I bought two diamond stones (dmt bench stones) , the red coarse one and the green fine one. They have served me well as a good starting point. But BY FAR the best investment for sharpening IMHO is a good book on the subject. The one by Leonard Lee is excellent.

With my dmt stones I sharpened my Stanley chisels enough to do mortises decently and cut myself by dropping one. By using them I learned the difference between somewhat sharp and completely dull.

Keep at it, have fun and be safe

-- No, I don't want to buy the pink hammer.

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12strings

433 posts in 1137 days


#9 posted 12-30-2013 01:48 PM

I used that 4 sided hf diamond block for sharpening for several years with good results…you should be able to get a usable edge with it, ...the only thing is, since you aren’t going to a very high grit, that the edge will not be very durable..it will dull faster than one sharpened on a high grit sharpening stone or high grit sandpaper. And it won’t be as sharp, but it should be usable for many tasks.

-- I'm strictly hand-tool only...unless the power tool is faster and easier!

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wtnhighlander

10 posts in 379 days


#10 posted 12-30-2013 03:00 PM

Invest in a decent honing guide. I used to freehand all my stuff, and could get a very nice edge, but using a guide makes it happen in FAR less time, and keeps the cutting edge square to the sides.

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TheWoodenOyster

1057 posts in 688 days


#11 posted 12-30-2013 04:03 PM

I believe I know that maniac who was sharpening the chisel with a belt sander. His name is Allan Little, also known as askwoodman. I have watched his videos about re-establishing a bevel with a belt sander, but that isn’t his final sharpening step. He goes on to do more to put his final edge on. He just uses the belt sander to fix chisels that are really screwed up. I would not advise using a belt sander for your final step unless you plan on using that chisel for home defense.

As far as whether or not you need sharper chisels for harder wood, without getting too complicated- yes you do. Harder fibers need a sharper blade to slice through them.

There are a billion and one ways to sharpen stuff and everyone thinks that they have the secret, myself included. The honest truth is that there are plenty of ways to get something sharp, and most of the tips you read in this forum can work if done properly. Tormek, scary sharp, oilstones, diamondstones, waterstones, freehand, honing guide, blah blah blah. It seems to me that the one constant in sharpening is that it takes everyone a while to figure out, no matter which system they use. It really is more about practice than the system you use. I use diamondstones and a strop, but have also used waterstones to get a great edge. I do not doubt that all the guys who have posted above have effective and efficient systems for sharpening. Probably just as good or better than mine.

My advice is purchase the parts and pieces of a sharpening system and start sharpening. It’ll probably take you a month or two to get it down, but keep at it. Like Loren said, Don’t go crazy putting mirror finishes on everything. You’ll need a mirror finish for paring, but for chopping it is not worth the time. Do what you need to do and don’t go overboard.

The only piece of equipment that I do tell everyone to get/make is a strop. Just a piece of leather with green compound glued to a board. It’ll be the cheapest sharpening equipment you own and it will serve you well.

-- The Wood Is Your Oyster

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drpdrp

150 posts in 799 days


#12 posted 12-30-2013 09:19 PM

No askwoodman- I watched him build that rubo (?) workbench and he is on my woodworking hero list! No this guy calls himself pilotman or some such? He does another video about making dovetails with the bandsaw.

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brtech

714 posts in 1675 days


#13 posted 12-30-2013 11:24 PM

So, since you seem to mostly shop at HF, I’m guessing a Tormek is not the right direction.

I think a lot of folks starting out think that the sharpening tool is the issue and not the human. That’s wrong. The tool helps, but unless you understand how to sharpen, you can’t get good results.

If you are on a budget, I think scary sharp is your best method. The downside to scary sharp is that you use sandpaper up relatively fast. I think that’s just not an issue for a typical beginning woodworker, and since it’s, by far, the cheapest way to start, and since it teaches you everything you need to know to sharpen, it’s the way to go.

So get a couple pieces of glass, some abrasive paper (you really mangled that chisel, so start with 120), 220, 400, 1200 and then at least 2000 (automotive wet/dry), and maybe a something higher (check out Lee Valley, they have a nice option). You can even skip the glass and use your tablesaw top.

Then you have to decide if you need to start with a guide to hold the proper bevel angle, or if you can learn to free hand. If you want to try the free hand method, find Paul Sellers’ video. You can do exactly what he does on his stone on your paper over glass. If you need to start with a guide, the cheap one works, the Lee Valley guide is universally liked.

Then search for “Scary Sharp” and you will find the basic process. It’s straightforward: use a spray adhesive to hold the paper to the glass. Flatten the back, walking up the grits, cleaning off the blade between grits. Then free hand, or use the guide to set the bevel.

If you want to microbevel, after you establish the primary bevel, you adjust the angle a bit more and run through the last few grits.

If you can get the edge to be sharp enough to shave hair off the back of your hand, it’s probably good enough. If the abrasive paper starts to get to be a pain to use up, then, maybe consider going to a set of diamond plates. You can go to a motorized scary sharp (Worksharp), but it’s the same process (abrasive paper on glass) with less effort. You can also use a strop after the finest grit abrasive paper.

Using a grinding wheel is usually only needed for a seriously mangled blade. It’s faster than starting at 120 and working out the nicks, but you need a somewhat deft touch to avoid ruining the blade temper.

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MalcolmLaurel

216 posts in 376 days


#14 posted 12-31-2013 12:01 AM

What’s the prevailing wisdom on Arkansas stones? I have a set of three that I inherited from my Dad (actually I think I bought them for him for Father’s day, years ago, from Brookstone back when they still sold useful tools). I also have his much older 2 sided silicon carbide Norton oilstone that he gave me years back, which I’ve used to sharpen knives for years.

-- Malcolm Laurel - http://MalcolmLaurel.com https://www.etsy.com/shop/MalcolmLaurel

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brtech

714 posts in 1675 days


#15 posted 12-31-2013 01:08 AM

They work as well as they ever did, which means they sharpen just fine. The problem is that, like with any stone, it wears unevenly, because it’s hard to use the surface uniformly. With harder stones, like oil stones, it’s harder to flatten them. The same thing happens with waterstones, but because they are softer, they flatten easier. Surgeons still use them to sharpen scalpels, so you know they have to work.

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