I have old tools from Sorby that test the same Rockwell as modern HSS steel . Can the Rockwell test indicate whether I can use the old tools on a new CBN wheel ?.
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HSS hi speed tool
- Thread starter Marc Erthein
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Lance Mirrer
AKA "taxman"
Interesting. Does the Rockwell test measure metallic structure or only hardness?
I believe any Sorby listed as HSS is fine for CBN wheel.
I've had lots of Sorby's - both carbon type and HSS. I recently came accross my first HSS in the old style orange handle with Kangaroo label. I've always assumed the older handles were old steel.
More pertinent to your post, if you use not HSS on the CBN, it does not hurt the wheel, the weaker steel fills the wheel with particles which require cleaning to remove. Once cleaned, the wheel is back to new.
I believe any Sorby listed as HSS is fine for CBN wheel.
I've had lots of Sorby's - both carbon type and HSS. I recently came accross my first HSS in the old style orange handle with Kangaroo label. I've always assumed the older handles were old steel.
More pertinent to your post, if you use not HSS on the CBN, it does not hurt the wheel, the weaker steel fills the wheel with particles which require cleaning to remove. Once cleaned, the wheel is back to new.
john lucas
AAW Forum Expert
Just buy the Slick Stick from woodturnerswonders. You can then grind any metal without damaging the cbn wheel. High carbon steels can be hardened just as hard as hss. Not sure why they can clog a cbn wheel where hss does not. Obviously has to do with structure of the steel.
The old sorby orange kangaroo tools from 1974 do not have HSS stamped on the tools. I’ve been using them all this time , buts it’s the advent ofCBN for me that makes me question their use.
But not carbide, right?
Do you use this also to clean the CBN wheel or is there something else? Thanks.
Well, not positive, but the Rockwell hardness test determines hardness and so many other things can change that. Grinding a "softer" steel on a CBN wheel can result is some build up on the wheel. If you have other HSS or V10 or M42 tools, they do a good job of cleaning that build up off. I tried the Slick Stick on my CBN wheels and didn't like it, just too thick. It does work nicely for bandsaw blades to keep them from gunking up when you are cutting green wood, and it is the best thing I have found for the soles of my hand planes, by far! I did have one old CBN wheel that was nearing retirement age. Just out of curiosity, I ground some soft steel, aluminum, copper and brass on it. There were visible lines on the wheel after. I went back to normal sharpening and within a month, there was no remaining metal left on the wheel to the naked eye. I have used the Trend lapping fluid on my wheels to help prevent build up. If you put the drops right on the wheel, stand out of the line of fire for a bit since it will leave you with a racing stripe on your shirt. I use a drop or so on the bevel of the tool I am sharpening. As for carbide, it can be done on a CBN wheel, but you will GREATLY reduce the life of the wheel. Diamond wheels or lapping plates only. There are diamond plates up to 8000 grit now days. No clue how they would work on the carbide tools since I have none of them in my shop.
robo hippy
robo hippy
Lance Mirrer
AKA "taxman"
The Slick Stik is a lubricant and helps the wheel before you dirty it. Don't think it will clean a clogged wheel.
I use PB Blaster penetrating oil to clean a wheel already clogged.
Robo, when you say the old wheel has no more metal, do you mean the softer metals were cleaned out by normal sharpening? Or did the softer metals ruin the wheel?
The recently acquired skew is the first Kangaroo handle I've seen with steel marked HSS. Reading the description of the Slick Stik, it preps the wheel to use softer steel. That said, I would heed Robo's warning that using the softer steel will "greatly reduce" wheel life.
Thanks for all the comments and good info provided!
Since you have a CBN wheel there is an easy test. HSS sharpened on a CBN wheel generates very few sparks. A hardened carbon steel tool will generate many more sparks. The important consideration with the non-HSS tools is to be careful to not overheat so you loose the temper. When HSS steel is sharpened and the tool's temperature isn't really a consideration.
I grind both HSS and high carbon hardened steel on CBN with no problems.
The thing about non-HSS is don't get the edge hot enough to turn blue or the hardness will be compromised.
A water wheel, such as the Tormek, is perfect for sharpening them.
With a normal CBN wheel, grinding hardened non-HSS gently and cooling often won't load up the wheel. At least, I've never had that happen.
If a hardened tool is not marked HSS, I treat it as if it is not HSS.
You can get a HSS edge red hot while grinding without damage (when glowing read just don't cool rapidly with water)
You can even use CBN wheels on non hardened steel or low carbon/mild steel without loading the wheel if you grind gently. I do this often on the flat sides a CBN wheel when flattening part of something such as a screwdriver.
Considering old tools, this has been mentioned before but some in my "old tools box" have not been hardened and some have only been hardened for the first few inches from the tip. Test with a file. I use a small triangular file - if the file "skates" on the steel, it's hardened. If it removes any metal (files a small groove) it is not hardened. When I find tools like this I mark the hardened length for future reference. (Old lathe tools with handles are great for shaping into custom, special use tools.)
Note: for determining the type of steel look up spark testing. I use spark testing most often to identify true wrought iron when I find unknown pieces around old barns.
Mark, do you have or have access to a Rockwell hardness tester? Or are the numbers the advertised numbers?
I used to use one in the lab but don't have access now. I'd love to have one but they're a bit expensive.
Has anyone tried the hardness testing files, such as these (I'm thinking of getting a set)
There is a little video on the page which seems helpful.
For $18 more you can get one with instructions in English...
Edit: I wrote this earlier and forgot send it till now. I didn't see David's msg about the overheating, sorry for the repetition.
JKJ
The thing about non-HSS is don't get the edge hot enough to turn blue or the hardness will be compromised.
A water wheel, such as the Tormek, is perfect for sharpening them.
With a normal CBN wheel, grinding hardened non-HSS gently and cooling often won't load up the wheel. At least, I've never had that happen.
If a hardened tool is not marked HSS, I treat it as if it is not HSS.
You can get a HSS edge red hot while grinding without damage (when glowing read just don't cool rapidly with water)
You can even use CBN wheels on non hardened steel or low carbon/mild steel without loading the wheel if you grind gently. I do this often on the flat sides a CBN wheel when flattening part of something such as a screwdriver.
Considering old tools, this has been mentioned before but some in my "old tools box" have not been hardened and some have only been hardened for the first few inches from the tip. Test with a file. I use a small triangular file - if the file "skates" on the steel, it's hardened. If it removes any metal (files a small groove) it is not hardened. When I find tools like this I mark the hardened length for future reference. (Old lathe tools with handles are great for shaping into custom, special use tools.)
Note: for determining the type of steel look up spark testing. I use spark testing most often to identify true wrought iron when I find unknown pieces around old barns.
Mark, do you have or have access to a Rockwell hardness tester? Or are the numbers the advertised numbers?
I used to use one in the lab but don't have access now. I'd love to have one but they're a bit expensive.
Has anyone tried the hardness testing files, such as these (I'm thinking of getting a set)
There is a little video on the page which seems helpful.
For $18 more you can get one with instructions in English...
Edit: I wrote this earlier and forgot send it till now. I didn't see David's msg about the overheating, sorry for the repetition.
JKJ
He was referring to sharpening carbide on a CBN
I use the diamond plates to touch my Carbide gouge tips and they work fine. But being plates I expect to replace them fairly often,luckily they are not expensive
I generally regard old tools as not being HSS, especially if there is no markings
Some of my HSS tools produce showers of sparks on the CBN wheels while others. None at all. Kdoes that mean that some producers of tools aren’t delivering what they advertise ? Should I avoid those with lots of sparks ? The old Sorby tools produce showers but they are NOT marked HSS just Sheffield.
That shower of sparks means high carbon steel. The ones that have no sparks, or just a few dull ones are HSS. That's one of the quick ways to tell.
I have access to a tool and die shop professional tester and they both came up with 60 Rockwell but one sparks and the other no.
john lucas
AAW Forum Expert
I wanted to measure the inside angle of Hunter cupped carbide cutters. I ground 1/4" off of a 1/2" hunter carbide cutter. Did not hurt my Dway 180 grit wheel. Of course you wouldn't want to grind the top of a flat carbide. I have also sharpened concrete drills that are carbide tipped..
No carbide involved in my question. Just can I sharpen the tools that show sparks on my new CBN wheels without permanenly damaging the wheels as they were expensive. Most of my tools are stamped HSS and even they show sparks some not. I think I’ll just go ahead and not worry about all the warnings. Thanks all for your comments
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Well going back over the thread, I see that no one has really answered your questions - most of them just talked over ya. Rockwell test for Hardness would tell you next to nothing about what sort of steel you are grinding (Which is what you really want to know about for CBN Wheels) Rockwell can just tell you how hard your steel is, whether it is M2 HSS or High Carbon (You could probably get a identical hardness test on either type steel!)
With CBN, it's a very hard matrix grit that will cut fast through Hardened HSS, but because of the nature of how it cuts, it can clog up when grinding High Carbon steel (because the metal in sparks can be hot enough to melt and turn into hard smooth slag on that microscopic level) and it can be difficult to clean it up afterwards (and because of the hard shell of slag, it "buries" the cutting grit of the CBN wheel so it does not cut efficiently any more) - But as others said, a little work can clean it up, but more often than not you can be find grinding any type of STEEL (not carbide which is too hard for CBN) on a CBN wheel with no trouble if you take a few precautions such as not doing any heavy grinding causing high heat & blueing of the metal (Which would ruin a High Carbon Steel tool anyways)
So to answer your original post question , no Rockwell test wouldn't really tell you definitively what sort of steel you have to work with.
Sometimes seems there are exceptions to everything, including conventional wisdom.
I might not sharpen carbide wood lathe tools on CBN. However, I have a friend who after trying my fine CBN wheels, bought one for a bench grinder just to sharpen certain carbide bits for his metal lathe. He said he uses a light touch and I think mechanical support and said it works. He uses a microscope to evaluate the before and after sharpness. I've never watched so I don't know if he does anything special. IIRC he's used it for 4-5 years now.
Diamond wheels would be better for carbide but are not appropriate for sharpening carbon-based steel, also important for metal turning, at bench-grinder speeds.
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john lucas
AAW Forum Expert
As I mentioned above I ground the he'll out of a Hunter carbide cutter on a cbn wheel. Did not hurt it at all. Nobody would grind as much carbide as I did for this experiment.
I did some searching and could not find another source for the Slick Stick for cbn wheels. There is another product called slick stick but it's totally different. What woodturnerswonders sells is called Wonder slick stick.
I did some searching and could not find another source for the Slick Stick for cbn wheels. There is another product called slick stick but it's totally different. What woodturnerswonders sells is called Wonder slick stick.
See if I can remember everything..... Difficult now days! The metal build up on my CBN wheels was not visible to the human eye, so just sharpening my M42 and V10 tools removed all the build up. Some places, maybe Packard turning supplies, do sell a hard aluminum oxide chunk for cleaning CBN wheels. It does make a LOT of dust! As for sharpening carbide on CBN, you may be able to do it some times, but I would not make a habit out of it. Carbide is harder then the boron particles on the CBN wheels. If you need to sharpen carbide, you should have diamond wheels. There are now diamond wheels for the Tormek and similar wet wheel systems. They start at 600 grit, but I can see the need for coarser grits. I think the Tradesman grinders out of Canada also make/has diamond wheels. The whole thing about diamond is that it is the hardest material known to us for now. In theory, they should last forever, but I would expect them to far outlast CBN. I did ask DMT if they made an 80 grit diamond plate, and they didn't quite laugh, but I could use one some times when I am restoring an old plane blade, one of the bimetal ones that couldn't cut cool butter.... The coarsest diamond plates I can find are 120. It takes a long time to get all the way down on the primary bevel at 120 grit! For my bench chisels and plane irons, I do use the CBN wheels, and I do take a lot of care to make sure I don't over heat the metal since most of them are not high speed steel. I do prefer to shape the primary bevel with the CBN and then do the secondary bevel with my diamond plates. As near as I can tell, Woodturning Wonders is the only place that carries the Slick Stick.
robo hippy
robo hippy
Rizza ordered diamond plates for me in a variety of grits. He said almost any grit and size was available, I just had to wait a bit.
Amazon for Slick Stik?
Amazon for Slick Stik?
As TO CBN nad Carbide according to Google AI and this to me sounds about right. Yes, hardness tells only how hard it is in general, Tungsten Carbide can be made harder the HSS but again the grade is also important.
While technically possible to grind tungsten carbide with a CBN wheel, it's generally not recommended because CBN is not as efficient or effective as a diamond grinding wheel when working with the extreme hardness of tungsten carbide; using a CBN wheel can lead to faster wheel wear, potential damage to the carbide material due to excessive heat generation, and may not produce the desired precision finish.
Key points to consider:
When to use CBN wheels:
While technically possible to grind tungsten carbide with a CBN wheel, it's generally not recommended because CBN is not as efficient or effective as a diamond grinding wheel when working with the extreme hardness of tungsten carbide; using a CBN wheel can lead to faster wheel wear, potential damage to the carbide material due to excessive heat generation, and may not produce the desired precision finish.
Key points to consider:
- Hardness comparison:
Diamond is the hardest material available, making it the optimal choice for grinding extremely hard materials like tungsten carbide.
- Heat generation:
Grinding tungsten carbide generates significant heat, and while CBN can handle some heat, it may not be able to dissipate it as efficiently as a diamond wheel, potentially leading to material damage.
- Wheel wear:
Due to the hardness of tungsten carbide, a CBN wheel will wear out much faster compared to when used on softer materials, requiring frequent replacement.
When to use CBN wheels:
- Hardened steel:
CBN wheels are excellent for grinding hardened steels, which are significantly softer than tungsten carbide.
Superalloys:
CBN can be used on high-performance alloys where extreme hardness is required but not as high as tungsten carbide.
This does not relate to the OP's question, but as it has come up, CBN is only about 66% efficient as diamond at grinding carbide and the CBN will get knocked about much more than diamond (edit: which Hughie has also posted while I was writing this
), but if you only have a little bit of carbide to grind occasionally that will be much cheaper than buying a dedicated bench grinder diamond wheel, and there are much cheaper ways to grind carbide than with diamond bench grinder wheel, which are very expensive now compared to CBN.
I have found the exception to the rule that diamond should not be used on HSS when used on a bench grinder is with the 'resin matrix' type diamond wheels. I've been using one of those with my HSS tools for a long time now, and more intensively for the first ten years, and I can confirm that it is still doing the job, with the occasional dressing. I only lost 0.02mm in matrix thickness the first seven years of use when that was my primary tool sharpening wheel and I was turning most days. I surmise that the temperatures required for the iron in the tools to 'absorb' the diamonds is not being reached, or whatever it is that is said to make diamond and iron incompatible grinding partners.
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I have one of those orange handle Sorby tools and it is clearly marked as HSS
Lance Mirrer
AKA "taxman"
Cool. This is the second HSS in Orange I've seen. Apparently, Sorby began offering HSS before changing handles. Having seen so few of them, I suspect it wasn't offered for long.
Can't see the business end of that tool, what is it?
Also - has anyone ever seen a Sorby carbon steel in their new handles?
Sorry if this wavered from the original post.
It was originally a parting tool with the coved top and the tapered body so that the bottom edge was about 1/2 the width of the top. The original configuration was capable of a cleaner cut then a conventional parting tool but it was almost guaranteed to catch and destroy the work piece.
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There are 5 orange kangaroo gouges and scrapers circa 1975 all of them not marked HSS. I have inspected then carefully and they test 62 Rockwell and marked Sheffield steel UK. I’m the original owner and used them all these years. I’m 95 old
The one that I have I think I bought it to cut the square to round on the balusters for the stairway to the second story that I added to my house in about 1972-3. The tool didn't work as advertised but I did learn to make the cut with the long point on a skew.
The grinder spark signature of the two types of steels is the best way to tell the difference as has been stated above.
This thread is seriously lacking in photos of examples.
Below is the best I've got but it only shows the spark signature of high carbon steel. On the first photo I was being a bit of a cowboy for visual effects, but note the stars at the ends of the spark trails.
This thread is seriously lacking in photos of examples.
Below is the best I've got but it only shows the spark signature of high carbon steel. On the first photo I was being a bit of a cowboy for visual effects, but note the stars at the ends of the spark trails.
I've been looking for this answer for so long. I live in the very south of Argentina and have wondered for some time now if carbon steels that were hardened to about HRC 62 could be safely ground on my CBN without messing it up, since I'm not finding a replacement down here any time soon.
I have a spindle roughing gouge made with a piston pin witch works wonders, but I've kept off my CBN fearing to harm it in any way. Not sure what steel or hardness of the piston pin is, but I presume it will be the same case as what you mention, where it will melt and clog up my wheel.
Anyone knows what the case is with grinding files on a CBN? (I know files are brittle and not recommended by many, but we've got little to no tools in Argentina so many people here rely on old files, mainly as skew chisels, where there is little to no overhang anyway, so the risk of it breaking is minimal)
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you should be fine - *IF* - Big IF - you take care to not grind heavily - CBN wheels are better suited to "sharpen or hone" (light grinding) and not well suited for shaping (I.E. grinding an old file from a square end into a skew), you'd be better off doing that on a normal aluminum oxide grinding wheel... However once you do have your tools shaped and ground to the bevel and shape you want, then by all means a sharpening on CBN should give you no problems.. as I mentioned just take care to not grind heavily or let tools get too hot on the wheel and they likely won't "melt" into the CBN...
You can absolutely sharpen hardened carbon steel tools on CBN wheels without damaging the wheel. I've done it often with old tools. HOWEVER, if you get the steel too hot it will lose the hardness, effectively annealing the steel. Won't hurt the wheel. The tool can be rehardened if you know the exact steel used and the hardening/annealing requirements.
I've read that if the tool edge get blue it's too late. (HSS can get red hot without harming the tool or the wheel.) When I sharpen non-HSS tools I first dribble honing fluid on the wheel, then make only very short grinds with light pressure and immediately immerse in water to cool the steel. Repeat.
Grinding softer metals, like copper, brass, aluminum is likely to clog the CBN wheel. Years ago Robo H wrote about some tests he did - if I remember correctly he found that sharpening HSS tools could help clean up a clogged wheel.
I've had a cbn wheel for over 5 years, sharpening both HSS turning tools and bench tools like chisels and plane blades with no evident problems. I use an aluminum oxide wheel for major reshaping. Cbn runs a lot cooler but no matter what wheel is used overheating will destroy the temper on high carbon tools. You can lower the heat with something like this. coolant sprayer
Marc, if you are still watching this thread, here is a bit more info. I inherited 8 Sorby scrapers from my father, who bought them in the '70s. They are not marked HSS, but I can easily tell from the spark pattern that they are HSS. I sharpen them on my CBN wheels and they do not clog the wheel or cause any other issues.
By the way, the steel in these 70's Sorby scrapers is so hard that, to raise a burr on them, I have to really work a carbide burnisher on them, pressing much harder than on my modern and high-end HSS scrapers.
john lucas
AAW Forum Expert
If you get the Slick Stick from woodturnerswonders and treat your CBN wheels with it you can grind quite soft metals on CBN without cloging the wheel. I've even ground aluminum just to see what happens. It doesn't hurt a thing although I would not recommend doing that. I've sharpened a lot of Carbon steel turning tools on my wheels without clogging after treating it with the Slick Stick.