Chisels not square after sharpening

[Todd Swanson Austin]

I'm trying to sharpen my chisels free hand on diamond stones. I can get them really sharp, however, the chisel looks like a skew chisel when I'm done with it. I'm not sure if its the pressure or some aspect of the technique or if the original bevel might be off? How do I fix this and also avoid making it happen? Also, I would rather improve my skill as opposed to using a guide.
Thanks

[harry strasil]

when sharpening free hand place the tip of your index finger in the center of the chisel close to the cutting edge when honing to maintain equal pressure on the edge. And only put gentle pressure on the tool with only your finger.

[Todd Ferrante]

The problem may be your process. You say you are using the stones to "sharpen" the chisels. The full set of steps to go from dull to sharp is as follows:
A) Using grinder, take back tip of chisel to eliminate old chips and make square.
B) Still using grinder, carefully grind correct bevel angle on chisel. It is not necessary to take the tip to a wire edge. Trying to do so may overheat the edge and ruin the temper, making a regrind necessary.
C) Use your coarsest stone to polish the back of the chisel completely flat.
D) Establish a microbevel on the tip of the chisel using the same stone.
E) Polish the back again to remove the wire edge.
F) Hone the microbevel front and back with each successively finer stone. Since the microbevel is already established, this should require very little pressure. At this point you are just using the stones to polish away the scratches left by the previous stone.

At some point, the microbevel and the back will be nearly mirror polished and you will be able to shave hair from your arm. This is where I stop honing. Some people then strop with polishing compound on a leather strop. This stropping can be repeated as you work to retain a super sharp edge without rehoning.

Todd F.

[Todd Swanson Austin]

OK, I don't have a grinder so I'm actually trying to hone the initial bevel with the stones as well. During this process it gets off square. I know it takes awhile, it should be possible right? I agree the micro-bevel is quick. I was putting too much pressure and not pointing one finger in the middle, I'll try that to see if it helps. I'm now wondering though whether that will correct the out of square problem now that I most likely made the bevel non square. I guess I could brake down and get the honing guide at least for working on the major bevel. I think with proper technique I shouldn't need the guide though.

[Jim Koepke]

OK, I don't have a grinder so I'm actually trying to hone the initial bevel with the stones as well. During this process it gets off square. I know it takes awhile, it should be possible right? I agree the micro-bevel is quick. I was putting too much pressure and not pointing one finger in the middle, I'll try that to see if it helps. I'm now wondering though whether that will correct the out of square problem now that I most likely made the bevel non square. I guess I could brake down and get the honing guide at least for working on the major bevel. I think with proper technique I shouldn't need the guide though.

Howdy Todd and welcome to the Creek.

Check out Derek Chohen's site, particularly the sharpening page:

http://www.inthewoodshop.com/Woodwor...ues/index.html

The 10¢ sharpening system may help. To spiff it up at a little more cost, you could add a dowel to make it roll.

if the blade is skewed when you are sharpening it, it will develop a skew to the blade. It may be a lot of work to get rid of a skew all at once by hand.

I have a flat disk sander set up for sharpening (Veritas MK II Power Sharpening System) if one is not careful, it can skew blades. My solution to this is to use both sides of the spinning disk to counter act the physics of the outside edge moving faster than the inside of the disk.

My preference is also for hand sharpening without a guide. When what you are doing does not produce the wanted results, analyze what is being done and compensate.

BTW, skewed chisels are often desirable for cutting dovetails and other paring tasks.

Hope there is some help in all of this,

jim

[Tri Hoang]

I think Todd & Jim pretty much cover it.

There are two distinct tasks here: one is to shape the blade/chisel, the other is to hone it. The shaping is normally done on the grinder. The honing is done on stones or sandpapers.

You need to shape it first and I'd recommend a guide to hold the chisel. You can then hone it using the same guide.

To reliably hone the chisel freehand, it's probably easier with hollow grind on the grinder. Without the hollow grind, you pretty hone the entire bevel if you follow it. Another problem with the flat bevel is if it's not really flat, you may not actually hone the tip of the chisel.

If you raise the tail end of the chisel up a bit, it's possible to hone just the small tip freehand. The problem with this is getting consistency across re-sharpenings.

[Steve Hamlin]

... problem with the flat bevel is if it's not really flat, you may not actually hone the tip of the chisel.

If you raise the tail end of the chisel up a bit, it's possible to hone just the small tip freehand. The problem with this is getting consistency across re-sharpenings.

Without a grinder, the real problem I find with this approach is the inherent bevel creep, which stores up a nasty reshaping problem when the angle at the tip gets too obtuse.
It is easier to get consistent results with a single flat or hollow ground bezel so it just snaps into registration on the stone,
By concentrating on a steady, even motion, rounded bezels can be reflattened by hand, and I'm more inclined to maintain the flat by always starting with a coarser stone (quick - ish) than repeatedly raise my honing angle.

That said, I am contemplating a grinding wheel, and do use a guide for repair or reshaping.

[Robert Rozaieski]

You can make do without a grinder if that's what you want to do. The grinder is simply faster and also, the hollow grind left from the grinder wheel makes registering the bevel while hand honing easier as only the tip and heel of the bevel will rest on the stone after it is ground. And you certainly don't need a honing guide and I don't recommend one if you want to learn to do it freehand. To learn to do it freehand...you have to do it freehand .

It sounds like your problem is one of pressure. If the chisel was square when you started and skewed when you were finished, then you are putting too much pressure on the low side. Go back to your coarsest stone and put more pressure on the high side and that should bring it down, albeit slowly.

Another option is to stand the chisel vertically and run it on the stone this way until the edge is straight. Then go back to the bevel. You will basically have a blunt chisel at this point, however, the blunt flat at the tip will help you gauge your progress. This is similar to grinding. You blunt the tip and square the edge first and as you grind you check your progress by watching where the flat is getting smaller. This helps you to direct your pressure to the area that needs the most work. If you pay attention to the flat on the tip and check it often, it will tell you where it needs work.

[Todd Swanson Austin]

Thanks everyone! After reading the posts and then doing some research on older threads I'm going to get a wet grinder and then do final touches and micro bevel maintenance by hand.

[Mark Roderick]

That's the way to go.

[Richard Francis]

http://www3.telus.net/BrentBeach/Sharpen/index.html
He has eschewed the grinder in favour of a coarse bench stone and a jig.
for $16 it may be the way to go.

[Tom Adger]

If you want it to be straight, I suggest you get a Veritas Mk II jig and be done with it. It is a very solid well built tool, and does a great job for me,and apparently a lot of other folks as well.

[lowell holmes]

You won't see it mentioned, but you can bevel and square the chisel with a mill bastard file before honing. I find that putting the file on the bench and using it like stone works quite well. The fellow that wrote the book "The Furniture Doctor" only sharpens with a file.

I do have a bench grinder I use most of the time.

[David Keller NC]

"Thanks everyone! After reading the posts and then doing some research on older threads I'm going to get a wet grinder and then do final touches and micro bevel maintenance by hand."

While I cannot more highly recommend the method of hollow-grinding and then honing on a polishing stone as the very fastest way to quit sharpening and get back to woodworking, there is an aspect to both wet and dry grinders that you may want to be aware of - even a Tormek (which I use), with all of its many jigs and stone truing tools, etc... will not guarantee that you can return a skewed edge back to square. This goes double for a dry grinder, in which a rest is used to support the tool but the squareness of the tool edge to the wheel is left up to the user.

On the Tormek, what can happen is that the chisel may not have absolutely parallel top and bottom surfaces. Particularly with a narrow chisel, that can result in skewing of the blade edge in reference to the stone, which of course results in a skewed chisel to some degree.

However, there is a way to get such a chisel back to square, and pretty easily. One takes a good 3 or 4" engineer's square (which you need anyway for other things, like dovetailing) and a scratch awl and draws a line as close as possible to the existing edge on the polished back of the chisel. One then uses this reference line to monitor progress on the grinder, and ensure that the end point is square to the chisel's sides.

Obviously, this assumes that the chisel has parallel sides, but even if they aren't quite parallel, one can usually pick an angle for the square that is very close to 90 degrees to the direction of push.

On the Tormek jig, you can simply loosen one of the hold-down screws and adjust the angle that the chisel edge presents to the wheel, and using the reference line, ensure that you get a hollow grind that's square. From there, it's really easy to work the edge to razor sharp on a fine polishing stone.

[Greg Crawford]

Todd,

Lots of great feedback here. You mentioned getting a wet grinder. If you know someone close that already owns one, maybe you could use theirs for a cold drink or a burger or something. Once you have the edge, honing should be OK for quite some time before you may have to grind again.