Carbide vs HSS

[leehljp]

I have 3 replaceable carbide bladed chisels and numerous HSS bladed ones.

I made my own favorite chisel from a rounded HSS scraper. Basically I ground it on a water wheel to a shape similar to a blunt (square) end but with about 10° angle because I am right handed.

I love the continued sharpness of my carbide but I get the finest cuts with my home made HSS. I keep a glass plate with 4 strips of psa micro sandpaper next to my lathe and swipe the blade every minute or two. To me, it stays sharper than I get with any new carbide blade replacement.

Yet, I read on this forum how sharp the carbides are and how well they cut. I haven't purchased any replacement blades in the last 4 years, so technology may have improved. And I remember a thread on this about 5 or 6 years ago in which the grain of carbide was discussed and it was mentioned that it was not as fine as HSS could achieve. Has this changed?

I would appreciate a discussion on this from the "technical" perspective. Thanks

 

[jttheclockman]

Short answer is no. Do not let anyone tell you different. It is the make up of the molecules of the different metals. HSS is smaller thus can be honed sharper.

 

[KenV]

I beg to disagree with John.

There is a huge difference range in qualities, granularity, and specifications in carbides, carbide treatments, etc. Most is used in the machine tool business and manifacturing.

The two most common commercial wood turning tools are Hunter and Easy Wood. Mike Hunter works his day job for carbide machine tool company. Craig Jackson background is as a machinist.

The grain size has progressively reduced to nano size and the polishing technology has advanced that the edges are very much the intersection of two planes and NO BURR.

The grain size with steel is a function of the alloy and the heat treatment. The finest grains of standard tools will be with the powdered metals. Then we put it against a grinding wheel. The grinding wheel gouges the steel and according to those who study such things changes the metal a bit. A burr is raised. And the edge is not polished.

Polished HSS and powdered steel polished can make some awesome cuts in metals, better than those from cheap insert carbides. And they can be brought to edges comperable to nano grain carbides.

But who do you know that hones and polishes steel edges after a trip to the grinder.

Note that when the fine grained carbides do chip, they leave a sharp jagged edge that looks more like what the grinder leaves on a fresh ground edge.

I am still not about to give up my powdered metal skew.

Will be glad to point you to some reference material.

 

[leehljp]

But who do you know that hones and polishes steel edges after a trip to the grinder.

I am still not about to give up my powdered metal skew.

Will be glad to point you to some reference material.

I was taught to do that 55-60 years ago by house building cabinet building uncles. But I didn't heed that until I started turning pens. Now, I will not use a "newly ground edge" on a pen - it has to be honed to a polish. All the difference in the world.

I saw a you-tube of a master furniture maker a few months ago. He tested the tormek and showed the finish of a well sharpened chisel and then compared to what he did by hand. His conclusion was that the tormek was very good as a rough sharpener, but honing was what made all the difference in the world.

 

[Schroedc]

What I've found IMO (I have some background in machine shops as well as woodturning) is that you can get a sharper edge on HSS tools BUT that the hardness is less than the Carbides so a carbide tool will stay sharper longer and gives the feel of a sharper tool. Also, sometimes how sharp it needs to be depends on what you're doing with the tool. Roughing out green wood? I'll use the 180 wheel on my grinder on my Sorby gouge and go right back to the lathe. Finish cuts on something with my skew? That gets honed to 6000 and polished. A lot of what I do is repetitive small turning so I prefer carbides in that situation as I'm not spending anywhere near as much time sharpening which means more output in my shop.

 

[magpens]

I made my own favorite chisel from a rounded HSS scraper. Basically I ground it on a water wheel to a shape similar to a blunt (square) end but with about 10° angle because I am right handed.

Lee,

I have been thinking of making a tool just like that.

So, do you mean that the end is at a 10* angle to the side ?
And that the acute angle is on the right side ?

What would be the angle between the cutting end and the top face ?

Thanks

 

[leehljp]

I made my own favorite chisel from a rounded HSS scraper. Basically I ground it on a water wheel to a shape similar to a blunt (square) end but with about 10° angle because I am right handed.

Lee,
I have been thinking of making a tool just like that.
So, do you mean that the end is at a 10* angle to the side ?
And that the acute angle is on the right side ?
What would be the angle between the cutting end and the top face ?
Thanks

Below are some picts of the end of a HSS chisel that was the upper end of HFs when they had 3 levels of turning chisels years ago.

• The first picture is the bottom and you can visually determine the bevel and angle.

• Picture 2 shows the miter angle that I chose by the most comfortable presentation angle to the blank for me. I am right handed. But I am considering a left hand one for getting into corners from the left side.
ALSO note that I put a very slight radius on the scraper. This is because when I had it straight, if my hand movement was off even a miniscule amount it would render a straight cut with a gouge. That very slight radius, guessing 12 in radius or more, helped considerably.

• Picture 3 shows the bevel angle.

• 4th picture shows the scraper from the edge so that the face is fully visible. And in this picture it is barely visible but the end used to be mirrow shined, and you can see a reflection of some writing on the box it was setting on. In the original picture when blown up, the writing was visible and readable. (And it has been 4 years since last used.)

I haven't used this chisel in 4 years as It has been lost until last week. I had tools in Japan and tools here in the USA. When I brought all of my tools home from Japan, my shop has been basically a storage shed for tools. I gave a dual bevel miter saw, a TS, DP and a few other tools to a son in law this summer, and found some of my tools from Japan.

I have been using carbide tools for some basic turning a few times in the past 4 years. They just were not as sharp as the HF chisel that I made into a scraper. Yes, I do sharpen it several times during a segmented turn, but I can tell the difference in feel between a very sharp HSS and a new carbide. The HSS beats the carbide for me, but I do loose time which is not a problem for me. For me, it is not about how fast I get something done, but how great I can make it. If I were to try making a living and needed production, I would most definitely switch to carbide full time. I was hoping that I would find carbide has become as sharp as HSS today.

 

[jttheclockman]

I beg to disagree with John.

There is a huge difference range in qualities, granularity, and specifications in carbides, carbide treatments, etc. Most is used in the machine tool business and manifacturing.

The two most common commercial wood turning tools are Hunter and Easy Wood. Mike Hunter works his day job for carbide machine tool company. Craig Jackson background is as a machinist.

The grain size has progressively reduced to nano size and the polishing technology has advanced that the edges are very much the intersection of two planes and NO BURR.

The grain size with steel is a function of the alloy and the heat treatment. The finest grains of standard tools will be with the powdered metals. Then we put it against a grinding wheel. The grinding wheel gouges the steel and according to those who study such things changes the metal a bit. A burr is raised. And the edge is not polished.

Polished HSS and powdered steel polished can make some awesome cuts in metals, better than those from cheap insert carbides. And they can be brought to edges comperable to nano grain carbides.

But who do you know that hones and polishes steel edges after a trip to the grinder.

Note that when the fine grained carbides do chip, they leave a sharp jagged edge that looks more like what the grinder leaves on a fresh ground edge.

I am still not about to give up my powdered metal skew.

Will be glad to point you to some reference material.

Ken, we will have to agree to disagree. I stand by my statement. Now for holding an edge of course the carbide will win out but that is not what he asked or at least that is not what I read.

 

[magpens]

Lee, thank you for the details !!!!

 

[KenV]

That's OK John,

I would have agreed with you 20 years ago, but today the best steel and best carbide, both with diamond "dust" polish, are close to a tie. But neither is sharp enough for some thin slicing labratory processes.

 

[Skie_M]

It's not that the carbide can have a finer CUTTING EDGE than a steel chisel, it's that it's MUCH HARDER than the steel chisel and will HOLD THE EDGE THAT IT HAS for far longer than any steel chisel.


Now, if you could take the time, with a range of very fine diamond or ceramic carbide grit stones, to polish out the edge of your carbide tool's cutting edges ... you'll end up with cutting action that is very nearly what you have come to expect from your favorite HSS chisel, but with 4 or 5 times fewer trips to your sharpening station, as it will hold those edges for far longer.

 

[leehljp]

It's not that the carbide can have a finer CUTTING EDGE than a steel chisel, it's that it's MUCH HARDER than the steel chisel and will HOLD THE EDGE THAT IT HAS for far longer than any steel chisel.

I was hoping that somehow with all the increase in technology over the last 5 or 6 years, the carbide of today would be able to offer the sharpness of an HSS.

I can FEEL the difference when turning with a just sharpened HSS versus a new carbide. It is a mile wide and it lasts about a minute when turning segments with brass in it. When I put on a new carbide of 4 to 5 years old (stored wrapped), it feels like the HSS after a minute or two on brass segments. There IS a difference. Of course the carbide will continue to turn for a long period like the HSS does after a minute or two on the brass segments.

For me to give weight to my OP, I need sharpness over longevity. Quality over quantity. I was hoping that carbide would be there.

Now, if you could take the time, with a range of very fine diamond or ceramic carbide grit stones, to polish out the edge of your carbide tool's cutting edges ... you'll end up with cutting action that is very nearly what you have come to expect from your favorite HSS chisel, but with 4 or 5 times fewer trips to your sharpening station, as it will hold those edges for far longer.

I can sharpen HSS with the best of them, but I can't get carbide to do that. I don't have the experience. Again, it is not about the time used it is about how sharp it is.

Thanks for the insights.

I guess my question has been answered, Carbide does last much longer, but HSS in the" just sharpened" state is much sharper than carbide can be. I was away for 3 to 4 years and a lot has changed in pen making and tools available. I was hoping that carbide would make such a leap in sharpness.

 

[Skie_M]

It all has to do with the perceived quality of the goods.

As for sharpening my chisels ... well, I put a nice mirror polish on those bevels that I can see myself in easily, and that's the way I like it! I even have a wooden wheel with a leather stropping belt glued on it that I use for the final honing, for several of my bladed tools.


Carbide chisel inserts are cheaply made and manufactured (in most cases) and then sold at a high markup due to their durability when used properly (again, in most cases ... there are some you can find out there for around 2 dollars apiece, if you look, and they are quite sadly JUST AS GOOD as the ones you pay 30 dollars apiece for). They are press formed using high pressure and heat and then ground to shape using diamond abrasive tools, then mass packed and sold. In other words, you get what you pay for.

If you go out of your way to find a manufacturer of C2 or C3 carbide inserts with mirror polished edges that are razor sharp, you will also find your way into a mess of lawsuits, as such small razor sharp objects will cut the hell out of someone's inept fingers as they attempt to mount them on their tool bit holders. It's literally a double-edged (or quadruple edged) knife, and it doesn't even have a handle to hold it safely by!

The manufacturers DO NOT put such a sharp edge on them for 3 reasons .... Safety of their own employees and end consumer of the product, longevity of the edge on the product (a much sharper, thinner edge would chip, break, or dull a little faster), and avoiding the legal hassle of dealing with lawsuits for selling such an unsafe product for handling.

This doesn't mean that you, the end user, have to put up with shoddy workmanship forever. You can get your own fine diamond abrasives and put a super polished edge on your carbide bits yourself and see how they are really supposed to perform. When you are finally comparing razor edge to razor edge, you see where the carbide comes out on top.

The problem is that carbides are so hard and tough, you really need diamond abrasives to sharpen them up, and getting abrasives fine enough IN DIAMOND is generally reserved for the jewelry trade (for grinding and polishing of sapphires, rubies, and diamonds). Aluminum Oxide happens to be sapphire ... it MIGHT be sharp enough to barely hone a carbide bit, but the paper it's backed with just wont hold up for long.


It was never that the carbides could "never" be as sharp as your HSS chisels .... it's just that they aren't sold that sharp purely for safety concerns and quality concerns. You CAN put an edge on them that will compare to your HSS chisel, it just takes the proper quality equipment to put it there and maintain it, and that equipment is NOT CHEAP. I've been looking for some time into getting simple "cabbing" lapidary equipment, and a single diamond grinding wheel (60 to 600 grit, any grit I wanna choose) would cost me over 300 dollars for a decent quality one.

You could run down to harbor freight and pick up their diamond faced sharpening block for about 12 bucks ... 200, 300, 400, and 600 grit faces. But the quality of those faces is fairly poor, and full of those diamond shaped holes, with random globs of diamond packed metal sticking up randomly... Like I said, the quality is fairly poor. Again, you get what you pay for.

 

[Curly]

Hank I'm of the HSS over Carbide for sharpness camp too. As each technology passes the last so to is carbide having competition with other products like ceramic and diamond based cutters so expect someone to try them in a wood lathe tool someday. When Carbide was overtaking HSS tooling in metal shops there were new and expensive alloys being used that were better able to hold their edges longer and under more heat and stress than HSS. They were overtaken by the carbides and have become hard to find. I remember there were at least four in an article I read but at the moment only Crobaloy and Tantung come to mind. They can take a very sharp edge and hold it much better than what you have with the HSS tools you are using now. You could search and see what sizes and shapes are still available and get one to play with. A small piece could be silver brazed to a longer bar without the heat having any effect on the alloy unless you quench it while very hot. It may develop micro-cracks. The makers would know for sure. You'll still be able to hone it to the same polished surfaces you do with your HSS and have the benefit of staying sharp several times longer. Don't let anyone touch it though. It may be to sharp to be safe and legal. ;

 

[leehljp]

. . . I remember there were at least four in an article I read but at the moment only Crobaloy and Tantung come to mind. They can take a very sharp edge and hold it much better than what you have with the HSS tools you are using now. You could search and see what sizes and shapes are still available and get one to play with.

Thanks Pete. I will look these up.
It just dawned on me that I do not see carbide on wood chisels used for flat work, dove tails or mortise and tenon. Sharpening must be the problem.

EDIT IN: I looked up carboloy and tantung and found this link at sawmill creek: http://www.sawmillcreek.org/showthread.php?185932-Tantung-steel You and I are not the only one who can tell that carbide is not as sharp as HSS. Glad to know that tantung inserts can be sharp or sharper than HSS and last somewhat like carbide. I just have to do a little more research and find some tantung inserts.

Thanks Pete, for putting me on to something different.



Skie - I have numerous diamond sharpeners and I have not been satisfied with them: too course for what I want. I have never tried diamond paste. I have two HF diamond squares and they do a rough shaping on HSS and I don't like that. I do better with my Grizzly "Tormek" copy. And then finalizing with PSA .5micron on flattened glass.

You mentioned two items that are preventing carbide from approaching HSS for comparative use: cost for sharpening and experience. $300 for home sharpening of carbide to compare to HSS is kinda high; and the experience needed to sharpen carbide is different from sharpening HSS. Most people do not know the sharpness attainable on HSS, and factory carbide sharpness is "good enough" for them.

I mentioned this in the reply to Pete and I will bring it up again. If Carbide is so good and sharp, why do we not see carbide on chisels used in flat work such as mortise and tenons, paring work, and dove tails?

I am surprised that some others here do not understand the difference between the sharpness differences in the two. I am going to do some research on what Pete mentioned.

 

[Curly]

Carbide is brittle and would likely not stand up to the prying and scraping activities of most woodworking chisel activities with the possible exception of pairing cuts.

I said earlier that one of the alloys was Crobaloy. I was mistaken, it is called Crobalt.

Now if someone would like to play with some HSS inserts in their carbide tool handles to see if they are sharper and can be honed even better than carbide, keeping in mind they won't have the life, then get some from Arthur R Warner Co to play with. They specialize in HSS inserts for machining. One can see if there are any sharpness differences with the two kinds of insert, eliminating any of the variables of how a different tool feels when compared to a familiar favourite. Have fun.

 

[jttheclockman]

Hank, maybe this would be of interest to you. I use the Trend system to sharpen my insert cutters. You do save a lot of money from buying just because they went dull and yes carbide does dull. You are correct not all diamond hones are equal. Takes special diamonds and methods of how they are applied.

www.penturners.org/forum/f14/honing-carbide-cutters-130966/

 

[KenV]

The discussion is moving in a good direction. Sharpness is not the paramount criteria. Sharp is only one of several factors to consider along with durability, sharpenability, etc.

The super sharp edge used in a labratory would last seconds, if that on a lathe.

Robo Hippy has you tube videos on tautang steel used by bowl turners on the Oregon Coast. Takes a very good edge that lasts and lasts to give excellent throughput for those in the bowl business.

I have a skew somewhere sold by craftsman back in the 90s with a brazed carbide edge. Worked well, but has to be sharpened on a diamond lap and that is very slow. Also brittle and chips when dropped. Getting rid of a chip with steel is easy and fast.

Lots of different things to consider other than the which is more sharp edge.