View Full Version : Sharpening HSS with diamond

09-08-2002, 01:24 AM
Read in a recent post that using a diamond wheel to grind steel will ruin the diamond wheel. Is this true? Why? I was considering using a diamond flaring cup wheel to sharpen end mills on my vertical miller. Part of the appeal of diamond was less abrasive debris than with a conventional wheel. Bad idea?

09-08-2002, 08:51 AM
You want to use a CBN flaring cup wheel. Looks similar to the diamond but is designed for use on steel. Works exellent and will not load up like a diamond wheel. Dianond wheels are for carbide.


09-08-2002, 09:29 AM
Hi Paul,
Can you suggest a place to get
CBN cup wheels at a good price?
I have needed one for a while but
can't justify 150.00 or more for the home shop use.
I also would like a gasher that wouldn't
break down in the corners.
Thanks ...Dave http://bbs.homeshopmachinist.net//smile.gif

John Stevenson
09-08-2002, 11:23 AM
Have a look at http://www.eternaltools.com/
Very nice people to deal with and they ship to the US.
They will make anything you want and don't charge an arm and a leg for it.

John S.

09-08-2002, 12:36 PM

Diamond is just crystallized carbon. Iron has an affinity for carbon and wants to incorporate it into its structure. (Think of carbon steel!) At high temperatures -- such as grinding iron based steels -- the carbon (diamond) will both oxidize (burn) and attempt to dissolve itself into the iron-based steel. At least that's the way I learned it.

09-08-2002, 02:25 PM
I've heard the same thing as tonydacrow. Also that you can significantly reduce the action if you keep the surfaces cool. When I grind steel with a diamond wheel, I set up my spray mist unit. Seems to work, at least for the little amount I do. But t&cgrinder has the real answer: get a CBN wheel for steel.

09-08-2002, 10:18 PM
Diamond or SiC can be used in any non-ferrous application (recommended use of both types) without worry. CBN is the best choice for steel, the next best would be Nortons SG series synthetic ceramic Alumina wheels (Norzon) - both wheels require care in setup and the makers recommendations should be followed for truing and opening the face.

09-09-2002, 04:29 AM
What is CBN?


09-09-2002, 06:49 AM
CBN (cubic boron nitride)

Norton abrasives makes an exellent wheel. CBN will generally be more expensive than diamond wheels. I have found I like wheels manufactured by a company called General Industrial Diamond. Co. They are located in Whippany, NJ. Next favorite is Standard Diamond Co.. They are located in Oswego, Il. Your local industrial tool rep should be able to get you info on them.

I have tried the Norton SG and really like them. Very good wheel for HSS.

I have found some great dels on ebay for grinding wheels. Lots of diamond and CBN wheels there. Shop wisely and bargains can be found.

Price wise I have found the General Industrial Diamond wheels to be the least expensive and seem to last the longest for my applications. I use them on a daily basis in my regrind shop.


09-09-2002, 06:44 PM
the shop i work is in whippany n.j. , management there says it is cheaper to buy new than regind endmills including carbide, so cutters have become disposable, use them once and striaght in the **** can. as far as Genral Industrial Diamond Co. goes i've never heard of that outfit does anyone know if they are a manufacturer? i would really like to give resharpening a try, could it be lucrative?

09-10-2002, 12:14 AM
General Industrial Diamond co, 201-884-2500

The cost of your wheel will depend on factors such as size, grit, depth of diamond and such.

Many production shops do use end mills once and throw them away, But if you are only using say .250 depth on the end for a slot cut does it not make sense to have them cut off, resharpened and reuse them. You still are at full diameter.

Most shops are afraid of using cuter comp with their CNC machines. This would be necessary with reground tools and require imput by the operator. What this tells me is most shops do not have faith in the operator/CNC machinist to do his job.

I have always told my customers to figure on 50 -80% tool life with a regrind compared to a new tool. You must compare the cost of a new tool versus the regind cost and life expectancy.

Depending on the diameter of the end mill I say generally if it is under 1/2" carbide buy new.

Many times if only the OD is sharpened you will start to loose cutter effiencey due to the change in lip geometry. If you have and endmill remanufactured on CNC equipment it should recreate the original geometry and if you specifiy remanufacture to standard sizes you can get a practically new end mill in most cases for less money.

It is true you can buy inexpensive import end mills but most are not woth the money from what I have seen of them.


09-10-2002, 12:40 AM
Then why does the drill doctor use diamond wheels? Kinda sodomizes the logic. Not veing smartass, just curious.

09-10-2002, 01:25 AM
Because Diamond is dirt cheap. DeBeers has all the women convinced they are worth something - sure tool sharpening, mining equipment coatings, and eventually Super high temperature semiconductors - so Intel can finally make a pentium that runs without a heatsink (like they will be in business in 20 years! Hah!).

So, to answer your question, they don't give a rat's ass if the wheel lasts - it is under $20 and designed for the average consumer. Besides, tool people know better than to bother with the cheap consumer equipment - it cannot put proper edge geometry on expensive tooling for production use. Darex has a $14,000 CNC machine for that uses the proper Diamond or CBN wheels as required.

09-10-2002, 07:41 PM
I have to agree with t&cgrinder about the prices on Ebay. In 1975 when I bought my first 3-3/4" flare cup diamond wheel it cost $126.00 + shipping. Granted it was new but I recently won an Ebay bid for a lot of three diamond wheels: a 3-3/4" flare cup wheel, a 5-1/2" flare cup wheel and a 7"x1/2" straight wheel. The small flare cup wheel looked almost new, the other two looked that there was about 70% to 80% of the diamonds left. All three wheels were $26.35 and that included the shipping! Can't beat that price with a stick!
Regards, Ken