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
- Start date
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..