Chisel back prep - old vs new alloy steels

[John C Cox]

Hey all,

Finally getting a few good old chisels has been an interesting thing.... They behave "Differently" than the new modern alloy steels I am used to...

For example - back prep....

I have taken it as an article of faith that one must lap the backs of your chisels.... And with my modern alloy steel chisels - they don't sharpen right if you don't lap the backs on a plate when you sharpen to release the feather edge... Wiping them on a pants leg or uncharged leather doesn't really do anything useful for me.... And rubbing the backs on a charged strop can mess up the back geometry bad... A couple years ago - I spent a large amount of time and energy undoing chisel back trouble I had caused through my early zeal on strops....

But I noticed that none of these old chisels have lapped backs... Warren also mentioned this - but never went any further about their use practices and HOW they got around backs that aren't lapped... Steven talks about rubbing chisels on a coarse pants leg or uncharged leather to rejuvenate edges.... None of that works on my modern alloy steel chisels...

But... All that stuff works on the old plain, extra high carbon cast steel chisels of old... Even the really hard ones... You can wipe the feather edge right off the edge on coarse denim or uncharged leather....

Is that why we never find old chisels with lapped backs - but new alloy steel chisels basically have to have lapped backs - so they will sharpen right? Because uncharged leather or cloth really isn't effective on the modern alloy steels in use since the 1950's - so workers had to come up with an alternative practice - aka honing the backs as well as the bevels?

Thanks

[Frederick Skelly]

This should be a really interesting thread. Cant wait to see folks' thoughts.

I speculate - with no data whatsoever - that many oldtimers weren't as utterly fixated on sharpening as we are today. If the feather edge came off with a quick rub, that was good enough.

I for one am DEFINITELY coming to like O1 (Ashley Iles).

Fred

[Jim Koepke]

Back flattening may be a modern phenomenon due to our ability of more accurate measurement.

It is highly doubtful 18th and 19th century workers took a caliper to their shavings.

Many of my planes came to me set up how they were last used. Mostly they were capable of shaving wood from a board. Tuning them up made them able to be regulated to take a chosen thickness of shaving through their full range.

If a chisel could be made to do its work, that was probably good enough.

Now we have multitudes of people who are mostly doing woodworking in their spare time. Two centuries ago, people likely didn't have any concept of "spare time."

jtk

[Derek Cohen]

Hey all,

Finally getting a few good old chisels has been an interesting thing.... They behave "Differently" than the new modern alloy steels I am used to...

For example - back prep....

I have taken it as an article of faith that one must lap the backs of your chisels.... And with my modern alloy steel chisels - they don't sharpen right if you don't lap the backs on a plate when you sharpen to release the feather edge... Wiping them on a pants leg or uncharged leather doesn't really do anything useful for me.... And rubbing the backs on a charged strop can mess up the back geometry bad... A couple years ago - I spent a large amount of time and energy undoing chisel back trouble I had caused through my early zeal on strops....

But I noticed that none of these old chisels have lapped backs... Warren also mentioned this - but never went any further about their use practices and HOW they got around backs that aren't lapped... Steven talks about rubbing chisels on a coarse pants leg or uncharged leather to rejuvenate edges.... None of that works on my modern alloy steel chisels...

But... All that stuff works on the old plain, extra high carbon cast steel chisels of old... Even the really hard ones... You can wipe the feather edge right off the edge on coarse denim or uncharged leather....

Is that why we never find old chisels with lapped backs - but new alloy steel chisels basically have to have lapped backs - so they will sharpen right? Because uncharged leather or cloth really isn't effective on the modern alloy steels in use since the 1950's - so workers had to come up with an alternative practice - aka honing the backs as well as the bevels?

Thanks

John, what do you define as "lap the back"? Does this refer to lapping the entire back, or just the immediate back of the bevel?

I do not subscribe to the "lap the entire back of the blade", although it is a nice touch and I am happy to see it done since it is a sign of a well manufactured chisel. Even flat is unnecessary to make a chisel work, but I would rather have a flat back that one that is curved. I believe that it says much for the skill of past furniture makers, who could produce quality with lesser tools than we have today.

Now are you saying that the rear of the blade is untouched in its entirety? That I could not understand since sharp required two edges meeting equally. Simply wiping a wire away does not say much about the quality of the edge, only about the steel.

Regards from Perth

Derek

[James Pallas]

I needed to get out a really big spoon to stir this pot. If you polish the whole back of a chisel don't you need to polish it every time you sharpen up in order to maintain it. If you just work the last 1/2 inch or so you will soon be out of flat if you use the chisel much.
Jim

[Patrick Chase]

This is a somewhat tricky topic IMO, for a couple reasons.

For starters I strongly disagree with the premise that "new alloys" require working the back with any sort of abrasive. I strop almost all of my tools on uncharged leather and it works perfectly well. I can strop most of them on my bare hand if need be, for that matter. As James says, if the edge is clean to begin with then it will hone without any lapping.

The reason I say "most of my tools" is because while old vs new is completely irrelevant to this topic, tough vs brittle is matters very much. Tough steels can withstand a lot of plastic deformation without breaking, and that leads to tenacious wire edges. As an extreme example, HSS at typical "Western tool hardness" requires more than just bare leather to remove the edge (though my PM-HSS Japanese chisels at Rc64 are sufficiently brittle that they don't).

Another example is austempered steel as in Narex and maybe a couple other brands. Those are on the soft side (Rc59 is just about the limit for lower Bainite) and *very* tough. I can get a clean edge with my Narex chisels on just leather, but it definitely takes more care and double-checking than with otherwise similar conventionally hardened steels that are a couple points harder.

There is nothing magical or unique about old steels, except in nostalgic peoples' overactive imaginations.

[John C Cox]

I am kinda surprised by the responses - as I have since discussed with several woodworker friends in real life... Everybody thinks it is obvious and why "the old guys" don't really talk about it....

One old fellow responded - "Yeah, everybody knows all that... The trouble is that they quit making the stuff like what you are talking about back in the 50's.. So you can't really buy anything like it anyway unless you know somebody with a collection"...

[Derek Cohen]

Hi John

Will you comment on my queries, above.

Regards from Perth

Derek

[steven c newman]

While you are about to flatten a chisel's back...look at your thumbnail....note it's size. That is all you need to work on, just the area the size of your thumbnail...

I use the pants leg as a quickie strop...2-4 swipes on each side...bevel then back....then right back to work....Aldi's or Witherbys...all treated the same way. I want them sharp for the job I need them to do, when I need them....not after a full day at my non-existent "sharpening bench" . I get a chisel...do a full sharpening on it....and expect it to do it's job..nothing more. it is not so much sharpening as it is maintaining the sharpened edges. I might at the end of a project, have a maintenance day....go through and check out the users...if they need a bit of work, that is when I work on the edges. i want them ready to go to work, when next needed..without any fussing around. I really don't care IF I can see myself reflecting from a sharpened edge..have mirrors for that...

Leather strop? yes, but it has been charged up a few time with that "green stick" when needed. Strop was made from an old leather work belt....one that carried my nail bags while I worked building foundations of concrete. The "rig" was finally retired, when I got too old for that work. One of the nail bags supplied the leather face of my leg vise. The belt was cut down a bit, and used as a strop ever since. about..15 years worth? Not too concerned about it...I can get a new one just like it...$3 at the local Borg....

Remember this..you can polish a bevel or a back to a mirror like perfection...and it still will have trouble cutting a warm stick of butter....

[Todd Stock]

I would tend to agree with Patrick on toughness...the 1970's era Two Cherries blades take a bit more to release the wire edge than either the old stuff or the LN A-2 edges...tougher steel or force of habit...not sure which. A strop would give me a faster release, but I want a mirror polish on a good piece of the back in any case (think cutting binding & purfling miters), so the extra couple of strokes is acceptable, and working in abrasive materials occasions the touchups in any case.

[Charles Guest]

Doesn't one end up lapping a goodly part of the back of a chisel or plane iron simply because it's easier to register a good bit of the chisel on whatever media is being used? I mean, how would you actually only register say an eighth or so of the back of a chisel on a honing stone in order to lap only that very small portion? Seems ridiculous to try and with modern, fast abrasives bordering on absurd.

[John C Cox]

Now are you saying that the rear of the blade is untouched in its entirety? That I could not understand since sharp required two edges meeting equally. Simply wiping a wire away does not say much about the quality of the edge, only about the steel.

Warren has mentioned this multiple times... I looked over these "old" tools that I picked up closely to see if I coule find one to refute his position... Not one... I say "old" because I doubt the youngest of them is much older than 20 years old... Then there were a couple from somewhere between the 50's and then.. But the oldest of them looked to be over 100 based on the markings... None of them appear to have had the backs flattened or honed like we talk about on here... Either honing 1/4" to 1/2" at the back of the bevel or flattening the whole back... A few of them had backs which had been abused... But none of them looked like they had been flattened... In fact - the actual old sheffield cast steel still had almost all the "mill black" oxide finish intact on the back...

I never paid this much attention the last time I had a bout with old tools 10 or 15 years ago (and incidentally ended up with a couple chisels with giant humps on their backs)...

I personally find chisels much easier to control when the backs are straight enough... Do they need to be optically flat all the way across the entire back? No.. I just need them flat enough so they don't dive into a cut or push up out of a cut when working... And I do like to hone a good flat across the back of the bevel so I know they have a good edge. So I have picked out my candidates and set out flattened the humps and bumps out of their backs so I could get them to register right on the work...

I agree it's a testimony to their skills that they got good results out of chisels that I would have had trouble with on the wood.. But I suppose it was their day job and it's not mine...

In the process - I got impatient and honed the bevels to see how they would hold up on wood... You know - especially with Sir Paul declaring that Aldi chisels are the match of old quality cast steel (they aren't by a long shot in my hands)... I couldn't bring myself to do the evil "Ruler trick" on a chisel back - so I simply stropped them on dry leather... The feather wiped right off and they came out ultra sharp and their edges hold up very very well... Most of the modern alloy steels don't behave this nicely for me... Feather edges and wire edges tend to be much more persistent... And the strop may remove it after carefully honing the bevel and back - but it won't without taking a light pass or two on the stone...

After some test cuts - I finished cleaning up the backs so they would register right on the work..

[David Ragan]

Back flattening may be a modern phenomenon due to our ability of more accurate measurement.

It is highly doubtful 18th and 19th century workers took a caliper to their shavings.

Many of my planes came to me set up how they were last used. Mostly they were capable of shaving wood from a board. Tuning them up made them able to be regulated to take a chosen thickness of shaving through their full range.

If a chisel could be made to do its work, that was probably good enough.

Now we have multitudes of people who are mostly doing woodworking in their spare time. Two centuries ago, people likely didn't have any concept of "spare time."

jtk


So true

It is baffling to see the woodworking of yesteryear, w no modern alloys, sharpening 'systems' and so forth. Very humbling indeed.

[Charles Guest]

A lot of the old timers ended up using chisels that one would sharpen the same as a straight carving gouge, with a bevel on both sides though not as neatly done as a carver might. There's certainly nothing wrong with this and by definition they work fine for paring as just about any carver would tell you.

But, if you want a flat back they are relatively easy to make thanks to the abrasive choices we have now.

[Warren Mickley]

Some of the responses in this thread are kind of far fetched. If one is going to use a chisel for daily work for a lifetime, the amount of time he spends getting the back to a fine state is trivial. If on the other hand one plans to fool with a chisel in spare time and then buy a whole other set next year, the time spent bringing it into service seems like a burden. I am having trouble imagining using chisels with double bevels as suggested by some. Put yourself in the position of a craftsman- nobody wants to screw around like that.

Some guys seem to think that when they find a chisel or plane at a flea market, it has remained untouched since a fine craftsman last used it in 1790 or whatever. It is many times more likely that it was used by some farmer or handyman in the meantime. That some one ran it into the ground without much care or skill.

[Matt Lau]

I'd love to hear Stan's take on this, as he had to support a family with his chisels.

On my end, I'm a hack. Most older chisels I find are abused...ground at weird angles, sometimes with an angle grinder, bent, stepped on, rusted.

I think that most guys on the Creek are higher level craftsmen than many of these "carpenters"

[John C Cox]

That's probably true - and nearly all old fashioned manual furniture making was gone by the 1950's or 1960's... Largely replaced by large power machines which would chop out thousands of parts quickly and cheaply...

This region had a LOT of furniture making... But by the 60's - it was all basically furniture assembling... Nobody hand cut joints with hand saws and chisels...

I applaud the fellows who have kept the craft alive - as that world is mostly gone as a vocation/trade.....

[James Pallas]

Some of the responses in this thread are kind of far fetched. If one is going to use a chisel for daily work for a lifetime, the amount of time he spends getting the back to a fine state is trivial. If on the other hand one plans to fool with a chisel in spare time and then buy a whole other set next year, the time spent bringing it into service seems like a burden. I am having trouble imagining using chisels with double bevels as suggested by some. Put yourself in the position of a craftsman- nobody wants to screw around like that.

Some guys seem to think that when they find a chisel or plane at a flea market, it has remained untouched since a fine craftsman last used it in 1790 or whatever. It is many times more likely that it was used by some farmer or handyman in the meantime. That some one ran it into the ground without much care or skill.

Warren you have the experience with many things as woodworking goes. I agree with most of what you have to say. Having been around some real craftsman I think I've seen a lot. One thing I have no doubts about is the fact that all the good ones have their favorites. They all tend to have those special tools that they are so familiar with that if you handed the exact same make and model blindfolded they would know that it wasn't their tool. I have also seen those same people modify a tool in ways that another would probably not find useful. Some may find an absolute flat back on a chisel a necessity and another not so much. A double bevel chisel in the hand of an experienced carver has the same level of skill as a bench chisel in the hand of a furniture maker. Swap that around and each may look like a bear cub in boxing gloves. A lot depends on the type of experience the craftsman has. I think that when there was more hands on work involved in tool making that a tool passed through several experience tool makers the tools were better made and chisels were flatter if they were a quality tool. The craftsmen that were buying them knew the difference.
Jim

[Charles Guest]

The best paring chisel I own is a 14mm No. 1 sweep with very low-ground bevels on both sides. Like butta' I think the problem here is the notion that you have to have an absolutely flat back in order to make a flat surface. You don't. You can certainly do fine paring with a chisel that has a flat back, but it is far from being necessary.

[Warren Mickley]

Here is a portion of plate 14 from Roubo (1769) showing a chisel and a fermoir. As explained in the text, a chisel has one bevel and a fermoir has two bevels. Fermoir means clasp and as Salivet (1792) explains it is so called because the the steel is held between two pieces of wrought iron. When I talked to French toolmaker Michel Auriou, he was emphatic: "A fermoir is not a chisel."

In 18th century France a double bevelled tool even had a different name from a single bevelled tool. The idea that 18th century woodworkers were so clumsy that they could not maintain a single bevel tool is just not supported by evidence.

386259

[Jim Koepke]

In 18th century France a double bevelled tool even had a different name from a single bevelled tool. The idea that 18th century woodworkers were so clumsy that they could not maintain a single bevel tool is just not supported by evidence.

Figure 9 appears to be hollow ground whereas figure 11 appears to be flat ground for the full length of both sides.

jtk

[Charles Guest]

Here is a portion of plate 14 from Roubo (1769) showing a chisel and a fermoir. As explained in the text, a chisel has one bevel and a fermoir has two bevels. Fermoir means clasp and as Salivet (1792) explains it is so called because the the steel is held between two pieces of wrought iron. When I talked to French toolmaker Michel Auriou, he was emphatic: "A fermoir is not a chisel."

In 18th century France a double bevelled tool even had a different name from a single bevelled tool. The idea that 18th century woodworkers were so clumsy that they could not maintain a single bevel tool is just not supported by evidence.

386259

It's a No. 1 sweep. Regardless of what you call it, or the history of its nomenclature, it still does a wonderful job paring whether in the context of carving, furnituremaking, trim carpentry, or whatever. A chisel's back does not have to be flat to produce a flat surface. There is nothing wrong with a flat back, but it is not in any way compulsory.

[steven c newman]

Hmmm...needed end grain trimmed today..
386357386358386359

Used my chin to "power" the chisel through the cuts...food for thought.

[steven c newman]

A "Project" for anyone that wants to try it...
387056387057
1930's era Defiance by Stanley....1-1/2" wide
387058
I have removed most of the "mushroom" and shined the logo up..
Back is fairly flat, yet has a small bevel at the edge. Main bevel has two bevels going on, and a reverse camber..
387059
And....it doesn't say anything about ...Aldi's....either.....$2 chisel, qualifies as being "cheap"?

Needs a handle with a leather washer on the end.

[Joel Moskowitz]

Japanese chisels don't have flat backs - they are flat just at the cutting edge. Traditionally made English chisels were made slightly hollow - before side bevels were drop forged and were not used (pre-1850 or so) or hand ground in (post 1850 - 1930's? in the UK) the chisel was hardened and the grinder would figure would which side became concave because of the hardening - and put the bevels on the other side. Today Ashley Iles grinds intentionally their backs with a minuscule hollow - so that it is very easy to get a consistent honing across the back.

[John C Cox]

I do appreciate Ashley Iles doing that.

I have been scratching my head about why the touchmarks on some of my old chisels are on the front and others are on the back - even within the same brand and what appears to be similar markings and features..... And there's my answer... Of course none of them had slightly hollowed backs when I got them - they all come to me humped... At least I am getting better/faster at sorting out the humps....

I sort of wish some modern makers would go back to letting the grinders pick the concave side for the back... Cough cough Two Cherries..... Working humps out of modern alloy steel that's been hardened to the right level is a work out....

[Kees Heiden]

I always wondered about that one Joel. Many chisels back then were laminated. Not much choice which way you grind the bevel.

[John C Cox]

Steve,
looks like a sweet chisel project you got there.

I would take you up on the offer except that I am mostly full up on big wide chisels. I currently have a giant old 2" cast steel Sorby I am trying to figure out how to do something with it... It's a beast.

I am still jealous of your local rust hunt results... Useful chisels are very thin on the ground here....


A "Project" for anyone that wants to try it...
387056387057
1930's era Defiance by Stanley....1-1/2" wide
387058
I have removed most of the "mushroom" and shined the logo up..
Back is fairly flat, yet has a small bevel at the edge. Main bevel has two bevels going on, and a reverse camber..
387059
And....it doesn't say anything about ...Aldi's....either.....$2 chisel, qualifies as being "cheap"?

Needs a handle with a leather washer on the end.

[steven c newman]

387137
Added a handle, to make sharpening a bit easier...

[John C Cox]

Definately A very nice chisel you have there. How does it run on wood? The only way to know is to test it out...

[Warren Mickley]

I always wondered about that one Joel. Many chisels back then were laminated. Not much choice which way you grind the bevel.

On this forum "traditional" practice can mean a lot of different things. Toward the end of the 18th century the toolmakers had trouble welding cast steel to the wrought iron so chisels started being made without the lamination, and there has probably been some production of chisels without lamination ever since. For myself I would hesitate to call something traditional that did not span the 18th century.

I have not seen documentation of the technique Joel mentions (forming the entire bevel after heat treatment). It seems to me that if one were to grind after hardening that it might be easier to grind the back slightly hollow than to grind the bevel. I also think that a craftsman who was making 3000 chisels or more a year might find a way to reduce unfavorable warping during heat treatment.

It makes a big difference if one is going to buy a new set of chisels every year or if he aiming for a lifetime of use. I have some chisels that I brought into service 40 and 50 years ago. Whatever time I spent getting them into service is long forgotten.

[steven c newman]

Took about an hour...reverse camber is gone, 25 degree bevel was hollow ground...
.387151
Back WAS flat, other than a bevel right on the edge....had a serious back bevel..HAD
387152
Still needs a little work, I prefer the bevels to be flat.
387153
Cuts nicely, bevel up or down...
387154
Just a $2 chisel.

This other "chisel" was in a large tub, filled with tools....
387155
No. 175, 1-1/4", Made by Crescent Tool Co. , Jamestown, NY.

I did clean up the mushroom on it..
387158
But that 40+ degree bevel will take a LOT of work..
387159
Almost like it was used as a Cold chisel? Gasket scraper? Will do a bit of research on this "gem"...back was flat, BTW...

[Jim Koepke]

Will do a bit of research on this "gem"...

There is one of those in a drawer out in the shop. Here is a clip from an old Crescent Tools Catalog:

387170

Mine is a 1".

jtk

[steven c newman]

Would like to find out what angle to do the bevel at...40-45 is a tad too steep....

May start a sharpening thread on this style of chisel? Plumbers' and Electricians' Chisels...

Doubt IF these were made with a skew edge.....

[steven c newman]

Gave the chisel a 35 degree bevel. These chisels were hardened through out, by Crescent Tool Co.

Back was almost flat...gave it a bit extra.
387358
Not a biggie. Some Plumber had hit the side a long time ago....has a dent just back from the edge.
Edge was sharpened to 2K grit, then stropped..
387359
A single, flat bevel. Nothing fancy, nor complicated. NOT a paring chisel, this one is for chopping....and, driven by a steel hammer.
387360
May keep it in the Household Tool Kit...