My arms are tired, and I'm feeling stupid.

[John Dykes]

All -

Some time ago (several months), I ordered a 4 set of Hirsch chisels during a sale. I've really not touched them at all. Yes, I've got plenty of books and videos about how to get them working, but was waiting on the Charlesworth series to see his opinion \ technique. Oddly enough, he says to flatten the back - ;).

And I'm stuck or being stupid - or both. I don't remember what this 4 pack of Hirsch chisels cost me, but I'm tempted to splurge next time. I've spent probably 8 hours on the 1" - and my arms are sore! I'm using the DMT xtra-coarse (which is about 6 months old and used primarily to flatten my Shaptons). The 1" is close - the last 1/16 next to the edge. But I dread attacking the others (already some prelim work shows I'm in for a treat). I've heard that these are the same as 2 Cherries, but I think Hirsch are the ones that fail some flattness spec! (By golly these things are hard too!)

I'm tempted to pitch them - and raid the coffee can to get some nice Japanese chisels.

I think my technique is good - DMT on a granite plate even! It's just ungodly slow... Is my DMT worn out? Or am I just weakling? I've also used my 320 Shapton - seems to cut a bit faster, but not by much.

People complain about the time and effort it takes to tune a rusty plane. I'd take that every day, and twice on Sunday, before doing a new chisel.

A kick in the slats would be appreciated!

Respectfully,
- jbd in Denver

* Speaking of DVDs... My Jim Kingshott set of 4 arrived 2 days ago. I commend them to you... I did not even know his name until well after he'd passed... It will always be my regret to have never known him. He continues to be a treasure for the hand tools community.

-jbd

[Eric Hartunian]

It looks to me that you are trying to flatten the whole back of the chisel. You just need to worry about the portion of the back near the cutting edge. I mostly use Japanese chisels, but on my western chisels, I only put about 1/2" or so of the back on the stone (or sandpaper, DMT, whatever you use). This way, I am not trying to lap as much steel, and it goes by faster. I cannot imagine spending that much time on one blade.

Eric

[Michael Gibbons]

It looks like you received some less than ideal chisels. It shouldn't take that long to flatten them, though everyone will spend a little time on them. Try a little longer . If no go, buy new ones and use those for can openers.

[Robert Rozaieski]

Return them. No chisel should take that long to flatten, new or old. I've done both and never spent more than 10 minutes on a single chisel.

[Tom Saurer]

The quickest method I've found is a sander with 60 grit and then working my way up to 220. Once you've done that, then you can move to your stones, etc.

That being said, you've spent a lot of time and on them and should be done. Try some more and if that doesn't work, send them back.

I agree with the above note that said you only need to do the first half an inch.

[Wiley Horne]

John,

You may be an expert on flattening by now, but I'll mention this just in case. Look at the back of the one you've been working on a while. Are there scratches over the whole back? If so, the chisel is rocking on the stone like a rocking horse, and you're removing metal but maintaining the convexity. Plus wearing out your diamond stone. That's the difficulty with lapping anything convex.

What you want to do is focus your metal removal right in the middle of the convexity, and remove metal as quickly as possible from that place. You only want to abrade the highest spot. The whole thing about making a convex thing flat, is that you first need to make it a little concave--then it's easy to flatten. I'm not making this up--that's the only way to flatten something convex, if you're going to lap rather than do a spot-and-scrape operation like machinists do.

My advice is return those chisels, then call Joel at Tools for Working Wood and get a recommendation. He's honest and very knowledgeable and will sell you something that will meet your needs and pocketbook. Talk to Joel himself. No affiliation or financial interest, etc etc.

Apologies if you already know all this stuff!

Wiley

[Greg Cole]

I have some Hirsch mortising chisels.... can't say as they were remotely close to that "out of flat", but as the guys above have mentioned... you really don't need to flatten the length of the chisel only the business potrion on the tip. I don't think the Borg specials I have were that wonky (circa 2000 Buck Bros IIRC).
I think I spend about 30 minutes on all 3 chisels when they were new before I used'em.

Cheers.
Greg

[John Dykes]

Appreciate the feedback... Little disgruntled about the whole thing.

Chris Schwartz indicated to flatten 3 inches of the back, that's what I initally was shooting for. The result was a very pronounced ledge 3/4 up the back of the 1" chisel. This bugged me considerably (Figured if I was running against a flat surface, this would surely dig the chisel in). Filed that down - and tried to bring it down level. In that process, I think I tipped the edge into the stone a bit.

But yes, 8 hours is no exaggeration...

My hand plane and sizing stock skills are getting better, and I'm moving into joinery. Marking, chisels, sawing... planes were the easy part! I researched the Hirsch quite a bit... but not sure I'd do it again. Yes, I may give Joel another call... My Ray Iles 3/8 "pigsticker" arrived yesterday. I've sworn not to touch it till I can get a set of bench \ paring chisels working like razors.

Thanks again -

[Chris Friesen]

I've read in a couple places that the "fully polished" chisels tend to be more out-of-flat than the "regular" ones. I guess the polishing process isn't as precise as the grinding.

For sharpness you only need the back to be flat and polished down near the cutting edge. However, there's a school of thought that says you want the whole back (or at least the outer rim, like japanese chisels) to be flat because it makes the cutting action more predictable when you're being guided by one surface to pare another.

[Eddie Darby]

The quickest method I've found is a sander with 60 grit and then working my way up to 220. Once you've done that, then you can move to your stones, etc.

I would double that!
If you start lapping a surface without looking, then you can find yourself with sore arms. Take a magic-marker and darken the surface first, then place them on your flat lapping surface and lap a few strokes. Inspect how much area you have removed and how much is left to go.
If the amount of metal is daunting, then it's time to crack out the heavy weights, otherwise the the DMT should be able to do it in no time flat!:rolleyes:

My DMT x-coarse removed metal really fast at the start, and then it's effectiveness reduced some after use. I just wish that it was coarser to begin with, so that once this initial break-in period was done, the aggressiveness would be where the new stones are at the start.

Perhaps DMT should come out with a new xxx-coarse stone design, and call it the Lap-Master.:eek:

I have a set of the LV chisels that they claim as being flat, and they are getting more closer to bananas everyday. I can remember spending some sweat equity on them, only to find that my Mom raided my tools and used it to remove a nail.
The good news is that the nail was successfully removed, and so I now use my banana chisels from LV as decoys to protect the well hidden good ones from suffering a similar fate!!!!

The reason for flattening the whole back of a chisel is to do fine paring where you want to make a surface flat, and so you use the back of the chisel as a reference. Most of the time this flattening would be for planes, but sometimes you can't get access with a plane but you can with a chisel.

[David DeCristoforo]

"...only to find that my Mom raided my tools and used it to remove a nail..."

I hate it when that happens....

"The reason for flattening the whole back of a chisel is to do fine paring where you want to make a surface flat..."

Actually, only the area at the cutting edge and a thin "line" along each side need to be flat. The area in between is irrelevant. That's why the Japanese blades are ground hollow on the backs...to make flattening and polishing these areas easier. I have used a similar process on "western style" blades by simply grinding a hollow on the back of the blade. It was not "pretty" but it eliminated much of the effort needed to get the critical areas flat.

YM

[Don C Peterson]

"...only to find that my Mom raided my tools and used it to remove a nail..."

I hate it when that happens....

"The reason for flattening the whole back of a chisel is to do fine paring where you want to make a surface flat..."

Actually, only the area at the cutting edge and a thin "line" along each side need to be flat. The area in between is irrelevant. That's why the Japanese blades are ground hollow on the backs...to make flattening and polishing these areas easier. I have used a similar process on "western style" blades by simply grinding a hollow on the back of the blade. It was not "pretty" but it eliminated much of the effort needed to get the critical areas flat.

YM

I'll second that suggestion. I got a 2" Pexto chisel that was badly out of flat and finally in desperation took it to the grinder to hollow out the back a bit. When I only had to flatten and polish a thin area around the outside of the chisel, it went MUCH faster. I didn't grid the hollow nearly as deep as you see on Japanese chisels, just enough to remove the necessary material. The flattening process removed nearly all of the hollow. It dosn't look terrific, but it works fine.

I tend to disagree that you only need to flatten a very small area of the back, doing so would do two things that I find undesirable. First, as others have mentioned, it would prevent the back from being used effectively as a reference and make it more difficult to make paring cuts perpendicular or flush. Second, it seems to me that this would tend to establish a kind of back bevel on your chisel, making future sharpening more complicated than it needs to be. At least that was my rationale for doing the hollow grind rather than just trying to flatten a small (< 2") area of the back.

[David DeCristoforo]

"...it would prevent the back from being used effectively as a reference and make it more difficult to make paring cuts..."

If you hollow the area shown below as a gradient, the chisel will still "register" as you describe.

83409

YM

[Don C Peterson]

Yoshikuni,

I agree, but maybe I wasn't clear. What I disagree with is just flattening a small area (3/4" or less) directly behind (or above) the cutting edge. In the case of Japanese chisels, even though there is a hollow, the lip or edge around the hollow is flattened to be in plane for at least an inch or more.

[David DeCristoforo]

"What I disagree with is just flattening a small area (3/4" or less) directly behind (or above) the cutting edge."

Ahh... yes, that would be a different situation entirely. Sorry if I misunderstood...

YM

[Steve Rozmiarek]

Hold on a second everybody. Isn't it fair to say that a .001" or whatever is not really going to make much difference in anything you do with a chisel? Why is registration even slightly important? Seems to me that the only reason, and it is a valid one, to flatten the back of a chisel, is to enable it to be sharpened to an edge that does not have nicks? Good grief they are chisels!

[Gary Herrmann]

I assume the DMT is flat - have you checked tho? Maybe you did get a bad batch of chisels. Contact the manufacturer and see what they'll offer - even an exchange would be good at this point.

I've bought some beat up vintage chisels that took a long time to flatten, but 8 hours is much longer than I would have been willing to stand.

Belt sander has been mentioned. If you're game, maybe try 60 or 80 grit sandpaper on a piece of glass. Even with really dinged up old chisels I don't think I've ever spent more than 15 minutes at 80 grit on a single chisel. After that you progress through grits pretty quickly.

[David DeCristoforo]

"Isn't it fair to say that a .001" or whatever is not really going to make much difference in anything you do with a chisel...Good grief they are chisels!"

Yes it's fair to say. But we do have fun "splitting hairs" don't we?

YM

[Mike Henderson]

I've bought a number of old planes and chisels. Except when I bought them from another woodworker, none of them had a flat back. I think there's good reasons for making the back flat, but our ancestors produced a lot of furniture with tools that didn't have flat backs.

Mike

[Steve Rozmiarek]

"Isn't it fair to say that a .001" or whatever is not really going to make much difference in anything you do with a chisel...Good grief they are chisels!"

Yes it's fair to say. But we do have fun "splitting hairs" don't we?

YM

Great fun indeed!

[Phillip Pattee]

It may be your technique. If your arms are getting tired, it may be because you are actually moving the chisel around on the DMT with your arms--and this inadvertantly rocks the chisel slightly when you change directions. If this happens you will not get your back flat. Try holding your chisel in a comfortable position, press down firmly, stand up straight and rock your body from side to side by shifting your weight from one foot to the other. Keep your arms and hands basically immoble. As you rock back and forth, the chisel will move around on the DMT, but you should avoid rocking your chisel. You can easily move about in a figure eight and cover most of the surface on your DMT (I doubt that there is any error introduced by an out of flat abrasive, but covering the surface and switching directions will even it out).

[John Dykes]

Well - the plot thickens, and yes - I am, indeed, stupid.

After moving to a belt sander belt glued to a piece of granite - and doing more damage than good. I tired of the process and decided to try and fiddle around making a straight grain pin ala Jim Kingshott. About 20 seconds into it - I sheared off the top of my thumb... everything above the nail (which is more than you might imagine!).

The chisels are bad karma...

Might try new ones... hehehe :)

- Painfully,
jbd in Denver

[Steve Rozmiarek]

Yikes! Yep, time for a new set. List those on the bay.

[Gary Herrmann]

Uh yeah, those chisels are haunted.

[Martin Shupe]

I had a set of Two Cherries chisels as my first set. It took me hours and hours to flatten the backs. First, I had to use lacquer thinning to get the lacquer off. Then I used sandpaper, stuck to my jointer bed.

When LN came out with their chisels, I bought them, and sold my TC.

The LN's needed just a little flattening and sharpening, and they were ready to go.

I only wish the LN's had been available in the first place.

[Eddie Darby]

"...it would prevent the back from being used effectively as a reference and make it more difficult to make paring cuts..."

If you hollow the area shown below as a gradient, the chisel will still "register" as you describe.

83409

YM

Nice Tip! I like it!:D:D:D

[David DeCristoforo]

"About 20 seconds into it - I sheared off the top of my thumb... "

Ouch... I hope you have been following that thread about first aid kits....

YM

[Cliff Rohrabacher]

I know this is heresy but - - - belt sander?
It's what I'd do. Then, the hand stone.

No belt sander? Then, the coarse paper on a flat surface as suggested (supra).

How hard is the steel? A new #2 mill file might do it also if the hardness is between 46 and 50 RC.