chisel backs

[Ken S]

Yesterday I took a leisurely look at my approximately two dozen old individual chisels.  These are a misc. collection inherited or acquired  over the years.  Most were in service long before I was born, and most were last sharpened by previous owners.

Almost all have reasonably sharpened bevels.  Where they are not quite up to muster is in the backs.  None are badly pitted or have deep machine marks.  A good flattening and polishing session should make them first rate.

Many of these chisels are no longer available new.  We no longer manufacture nice Buck crank neck patternmaker chisels in different lengths.  Our selection of unbeveled chisels is also limited.

I believe these old chisels demonstrate a very common sharpening problem.  All too often, we worry about the bevel (or micro bevel) and give inadequate attention to the other side of the sharp edge, the chisel back.

Ken

[Mike Fairleigh]

Agreed Ken, where chisels (and plane irons too) are concerned, the back is just as important as the bevel.  And that one-time back flattening is a real pain on a lot of them.  I've found that for me, the easiest way to get there is with 3M Gold Stickit rolls on a granite plate, grits 80 thru 220.  I personally am not a fan of flattening chisel backs on the side of the Tormek wheel.

[Herman Trivilino]

Most were in service long before I was born, and most were last sharpened by previous owners.

That surprises me, Ken.  I would've thought you'd attended to them long ago.  If I have an ole tool like that it cries out to me to be sharpened on the Tormek.

You're right in that not much attention is given to chisel backs.  All the old chisels I've found or inherited had been sharpened many times, an with each sharpening the edge angle had been increased.  I attribute this to the previous sharpeners not having the right tools on hand.  Using whatever's on hand, such as a bench stone, and little patience, that's way most chisels and knives get sharpened.

It takes a lot more time and patience to flatten a chisel back, not to mention having the right tools on hand.

[Herman Trivilino]

I personally am not a fan of flattening chisel backs on the side of the Tormek wheel.

I consider it to be a quick and dirty method.  I don't like to do it too much because there's no way to true the side of the grindstone.

[Ken S]

Good points, Rob and Herman.

I have flattened the back of a nice old Buck chisel with the side of the Tormek wheel.  The chisel had a belly. 

I placed a straight edge across the side of my Tormek wheel.  To my eye, it looked true.  Part of me thinks it should work for back work.  Another part of me is more comfortable using a glass plate.  (Granite would be fine.  I just happen to have a glass plate. Granite would definitely be safer.)

I agree, Herman.  If I was a good person, I would have Tormeked all my chisels long ago.  Some of the blades were sharpened by unknown craftsmen, but some were sharpened by my Dad and grandfathers.  That's no excuse for my not polishing the backs.  Giving a chisel a proper polished back can be quite time consuming.  (Maybe that's a logical reason to own fewer chisels!......but, who is logical?)

There is certainly a joy in both fully sharpening and using a sharp chisel.

Ken

[Herman Trivilino]

I don't see why a long gradual belly in a chisel back would be a problem.  It seems to me that the back needs to be flat only locally, near the end.

Ken, when I sharpen one of the old plane irons or chisels that were owned by my father or grandfather I just know it makes them happy.  Of course, I know that my father's pleasure wouldn't last long, as he'd find some way to point out that with a machine as good as that Tormek they oughta be even sharper.   
   

[Rob]

I use the side of the Tormek and for the same reason I bought it in the first place, I really like it. For me I got fed up sharpening chisels and plane irons by hand.  I used to use a honing guide with an oil stone and always used a secondary bevel....simply to avoid sore fingers from the belly ache of having to regrind the bevel.

When I first used the tormek I simply couldnt believe how fast it reground the entire bevel and so with great glee moved swiftly onto lapping the backs (which is even more of a chore than the bevels if done soley by hand). And I confess to never having had problems with the side....I go very easy....have the wheel turning away from the edge and only just have the edge over the stone....literally a few mm only ie just around the edge.  Ive found it does a cracking job of lapping the backs.

Having said that...Ive never got into the more recent innovations of multiple grits of abrasive on a dead flat surface of i=either glas or granite.  So I guess that whole new "by hand" flat stone approach has been missed by me as I went from trad oil stones straight to the tormek.

Im going to a sharpening event next saturday where Im going to see these flat systems demo'd....also a tormek guy will be there.  It'll be interesting to see them in action.  But my original reason was sore fingers doing it all by hand and the tormek solved everything....and some

[Ken S]

Rob, like you, flattening the backs of chisels was what really sold me on the Tormek. I wanted to prepare my Blue Chip chisels for a hand dovetailing class.  I was using water stones, however, it was still a lot of work, and quite hard on my hands.  It was less work than using oilstones, which I have also done, but it was still labor intensive.

In hindsight, several things increased the work: 1) I should have started with the 220 grit water stone. Both the 1000 grit stone and my fingers were worse for the wear with that project.  2) No one thought of routinely dressing oilstones with a diamond plate back then.  3) Some chisels require a lot more work to flatten and polish.  The Blue Chips had a lot of machine marks.  Priced at twenty USD for a pack of four, one earned one's chisels with sweat equity, but they worked well after the work.  At fifty to eighty USD each, Lie-Nielsen and Veritas chisels require very little preparation. (just more time at the day job to purchase them)

Ron Hock came up with a very good idea to help backing.  He uses a foot switch to turn the Tormek on and off.  He places the chisel back flat against the wheel before turning the machine on and turns it off before pulling the blade away.

I think the ideal method may be a combination of the Tormek and either stones or abrasive paper with very fine grit.  Let the Tormek do the heavy lifting of flattening and removing the mill marks with the side of the wheel at 220 grit.  Then switch to the stones of flat surface for the final polishing.  That would combine the labor saving of the Tormek and the flatness of the fine abrasive.

Please post your observations of the sharpening event, Rob.

Herman, I think for many uses having a flat back makes no difference.  Certainly not for mortising in hinges.  Even dovetailing within reason.  I suspect many early chisels were only polished near the edge.  I have no doubt that many chisels are lucky to receive much work on the bevel, let alone the back. (Being nosy, I have looked at some of the chisels used by carpenters working on my house.  Perhaps their Tormek was in the shop that week........)

Ken

[Rob]

Good idea that foot pedal...like it.  Also that seems reasonable to do the donkey work with the T and then switch to refining with a 1000 grit or more flat stone.  I guess someone will try and sell me one at this event next week :-)

[Ken S]

Rob, rest assured.  Many vendors as your event will try to help your sharpening blues with various marvelous gadgets.  Enjoy!

Ken

[Herman Trivilino]

And I confess to never having had problems with the side....I go very easy....have the wheel turning away from the edge and only just have the edge over the stone....literally a few mm only ie just around the edge.  Ive found it does a cracking job of lapping the backs.

Rob, are you saying that you flatten only the few mm of the back that are near the edge?  I don't see how that's possible if you have the grindstone turning away from the edge.  What am I missing?

[Herman Trivilino]

Ron Hock came up with a very good idea to help backing.  He uses a foot switch to turn the Tormek on and off.  He places the chisel back flat against the wheel before turning the machine on and turns it off before pulling the blade away.

Ah ha!  I now remember that tip!  He mentions in his book that he suggested to Tormek a tip that he hoped to see in future versions, but he doesn't mention what that tip is.  It was discussed here a long time ago, but I'd forgotten it.  Thanks.

Of course, the new safety switch would render that foot switch useless!

[Rob]

And I confess to never having had problems with the side....I go very easy....have the wheel turning away from the edge and only just have the edge over the stone....literally a few mm only ie just around the edge.  Ive found it does a cracking job of lapping the backs.

Rob, are you saying that you flatten only the few mm of the back that are near the edge?  I don't see how that's possible if you have the grindstone turning away from the edge.  What am I missing?

Herman, this is generally the procedure I follow. I place the chisel significantly over the wheel so that I can avoid tipping it accidentally onto an edge. My goal at this step is to present the back to the stone flat on. Thus I want as much material to play with so I can stabilise it. Once its on, you can sort of get the vibe of where the stone is pulling it and I manipulate into a position that feels comfortable and controlled. Then I start slowly drawing it back off the wheel until the top left corner is as close to the edge as I dare have it without loss if control.  That means the right hand corner is a good way in.

What I've discovered through practice of this is that the more chisel you have in contact with the stone, the longer it takes.  So in always trying to minimise the protrusion distance. Its tricky because the less contact, the less control.  But for me its worth the risk to avoid that slog with the sore fingers doing it manually

I won't say I always avoid tipping it onto an edge but I'm extremely careful to avoid the cutting edge. I also always do this before sharpening and not the other way round

Lastly, I don't have any expensive chisels.  If Mr Tom Lie Nielsen had deposited some of his magic metal in my shop I might have a different view.  What I'm saying is that its not without its risks.

[Herman Trivilino]

Rob, I understand.  Thanks.  You evidently have the wheel turning away from you as well as away from the edge.

I basically do the same thing except I usually have the stone turning towards me, so the chisel is closer to the bottom of the grindstone than the top.

The thing I'm careful about is that I try to remove an even amount of material from the full width of the grindstone as there's no way to true it once it gets out of true.

I spend very little time on the side of the grindstone for this reason.

[Rob]

Rob, I understand.  Thanks.  You evidently have the wheel turning away from you as well as away from the edge.

I basically do the same thing except I usually have the stone turning towards me, so the chisel is closer to the bottom of the grindstone than the top.

Interesting....you know it never even occurred to me to try it that way round.  Mine is as you say, pointing up towards the top of the wheel.  I wonder if your method gives you more control?  Ill definitely try it