Thread: Your experiences with re-hardened chisels

Originally Posted by truckjohn

.... Is it worth the time and effort to reharden a "softish feeling" Stanley or Marples vs dropping the coin on a higher priced chisel such as a Hirsch or Ashely Iles?

My own experience with trying to harden & temper a butter-soft chisel was a bit of a disaster. I ended up with a banana that I managed to semi-straighten after some re-heating & hammering, but I could not get it tempered properly, and managed to break it in half through my own klutziness. The top bit wasn't as hard as the bit that broke off, but is still too brittle for everyday use - I keep it as a beater, & to remind me that there are some many things I need to know more about before I mess with them.

I'll leave it to those with real metal-working knowledge to detail the process, but my experience is that hardening them is the easy part. You do need to ascertain if it's an oil- or water-hardening steel you're dealing with, and you need a pretty decent heat-source for something the size of a chisel. The main danger in the hardening step is warping of that long, thin blade when you plunge it into the cooling medium, which is what happened in my case, even though I thought I followed instructions to the letter. If your hardening step goes ok, you then need to temper it successfully, & that is more of a dark art than step 1. Of course, it's do-able, and if you have an old clunker that is useless as-is, then you can experiment away to your heart's content. The only way to become competent at something is to practice it.

So in summary, it's probably not worth mucking about if you have no smithing skills & your main aim is working with wood, & you want to build up a set of good chisels in a reasonable period of time. There are sufficient new & old chisels out there that will fit the bill, and they are not too hard to find if you get serious about it. OTH, if you have an old chisel that's too soft to be useful & you would like to experience the way steel metamorphoses with heating & cooling, why not have yourself some fun?!

Cheers,

Working wood - Pfffftttt. That's crazy talk. I mean seriously - you would think this is a woodworking forum or something.

You life in the USA you have tones of good old chisels available. Why fuss about with heat treating trying to get modern junker chisels to be half usable, when you can get very good quality old Pre 1950's chisels for peanuts and for allot less work you can get them looking and working slick.

IF you must buy new, buy the best tools your money can buy - buy a good modern chisels by Veritas or Lie-Nielsen. You only need two chisels say 1/4" and a 1/2" will get you started for most furniture work. In time you can always buy a 1" & maybe a 3/4" and you will have all the chisels you will ever need.

Yeah - the good old tools situation around here is more of a myth...

then go new.

Originally Posted by truckjohn

Yeah - the good old tools situation around here is more of a myth...

Funny that, I've been chatting on some Yank woodwork facebook sites about this and it seems that this is true for some parts of the US. Some areas have a lot of old barns etc with lots of old treasures and other areas have nothing. I saw an old compass plane that some one bought for US$15.00. He wasn't even sure what it did! Lots of Bedrocks and block planes going from $10.00 to $25.00. It breaks my heart.

My uncle used to visit the states in the 70's and do a tour of the auto wreckers in the southern states buying up any V8 motors he could find. He'd fill up a couple of containers bring them back and sell them to boat owners. He did well out of that.

TT

The reason I ask is that (theoretically at least) performing the heat treatment correctly is as important as just getting the metal hard.

What does that mean? Well - apparently, you can get steel plenty hard without properly changing the steel structure in a useful way. And so - while your steel is still "hard" .. the edge retention acts as if the steel was a lot softer..... You get all the downside of difficulty sharpening and none of the benefit you expected in edge life..

That's what I am asking... When you guys did reharden the steel - did you get anything worthwhile?

Originally Posted by truckjohn

So.. How is the performance of re-hardened chisels? Is it worth the time and effort to reharden a "softish feeling" Stanley or Marples vs dropping the coin on a higher priced chisel such as a Hirsch or Ashely Iles?

I have successful hardened and tempered new, good quality, tool steel stock using a microprocessor controlled furnace at work.
Based on this I tried to rehardened a half dozen "soft" chisels and my experience parallels that of Ian's. A few bananas and little success.
Of these chisels I have kept one and it's debatable whether I improved it because even though I was successfully at hardening it a little, it does not seem to hold it's edge any better than before.
Because I was successfully able to hardened and temp new steel stock I put it down to the quality of the steel in the old chisels.

The process assumes the steel was made able to to be rehardened AND that it would then be able to form and hold a cutting edge. These two are not the same thing.

The steel itself could be from a dud batch or may deliberately not have been made to be as hard as you want it to be because it contains additives so it can be easily sharpened. It this case you will be flogging a dead horse.

Even if it can be made harder its grain structure may be too large, or if it's too brittle so may not form a decent lasting cutting edge.

Interesting, Bob. I reckoned you have far more metal-working experience than I, & would have had a much better chance of success, so it's both heartening & dis-heartening that you were similarly unsuccessful. I hadn't thought about it before, but what you suggest about the inherent hardenability of the steels makes sense. And there are certainly other desirable properties to a good chisel than sheer hardness of the metal. My old Titans are far softer than my Lie-Nielsens, yet they hold up amazingly well when bashed into our bone-hard hardwoods. Someone at Titan obviously figured out how to get the best set of compromises from the steel stock they used.

I do know that steels ain't just steels and that you have to follow particular protocols depending on the formulation. I've had good success hardening & tempering 'bright' steels that were bought soft and workable with files. I guess these are made for the simple heat-treatment methods available in the home workshop. OTH, I have tried using the upper ends of broken drill bits to make cutters, etc., and quickly discovered they are a completely different animal. The HSS hardens alright, but I simply could not back it off to a useable temper. Left hard, it has a coarse granular structure that fractures far too easily. If I do use old drill bits now, I put whatever profile I need on the remaining factory-hardened part at the ends of the lands or the part of the shank immediately above where it is still hard, and forget about any further heat-treatment...

Cheers,

Reason I am going on about this is that I rehardened the tips of some new production buck brothers and Irwin/Marples chisels. I torch heated them to do this.... Followed this with a quench in oil and they got plenty hard. Because of the aforementioned warp problems - I only hardened the first inch. I tested them out and a file would skate all day long and they would put deep scratches in new production chisels..

They were too brittle this way - so I tempered them back at 400F for an hour and they are now a little softer than as quenched but considerably harder than as new.

But the question remains in my mind... Did I gain anything other than the edge now doesn't roll as easily and a chisel that's harder to sharpen..

There's a pretty good chance that it worked because modern high volume chisel steels are chosen to be quickly induction heated, soaked for maybe 5-10 seconds, and quenched. And so torch heating the tips to nonmagnetic for 10 seconds and then quenching in warm canola fits their design... But that's just luck on my part if true. The sort of production method they use wouldn't work right with O1 or W1 or any other good high carbon steel but it works like a charm with stuff in between 5160 and 1084 steel...

Thanks

It's not the wood forum, but I belong to a couple of knife making forums and follow some makers on Facebook. I don't know of a www one.

They are some of the most passionate people I know. So obsessive and so unbelievably knowledgable.

Tempering and hardening is something they talk about in great detail. The whole process is very exact and a "guess" simply won't work. There are many here in Canberra who would gladly take your chisel and harden it to any Rockwell you desire.

They probably will also profile, polish and sharpen it to perfection.

These guys have the MOST incredible setups. Little digital electric furnaces, giant air hammers, special acids, amazing grinding tools (a friend makes one called "the Noob grinder" which is rather famous) and precission sharpening equipment.

Their wood stash is also incredible. They buy "scales" which are like pen blanks. They swap them like a currency, almost Pokemon Card in reverence.

Their work is beautiful and amazing.

I'd say they would be rather happy to heat treat your chisels for you.

Originally Posted by woodPixel

......I'd say they would be rather happy to heat treat your chisels for you....

Woodpixel, a good smith can certainly work wonders, but the OP is in South Carolina, USA, so postage to Canberra & back could put the price of the operation up to something approaching a Lie-Nielsen or two...

Cheers,

Originally Posted by IanW

Woodpixel, a good smith can certainly work wonders, but the OP is in South Carolina, USA, so postage to Canberra & back could put the price of the operation up to something approaching a Lie-Nielsen or two...

Mate! The yanks have perfected it to an art! The stuff they have there in the form of digitally controlled furnaces and temperature management is unreal.

Yeah, thanks for the offer but it's a bit of a drive.

The idea and process came from an Australian guitar builder. He hardened up all his Marples "rocket lolly" chisels and blue handle chisels rather than buying $$$$ chisels from The UK/USA/Europe. Said he was very happy with them. They performed well on gidgee, jarrah, wandoo, and the million various flavors of iron hard gum.

I figured that it was a more common thing to do down under.