Cobalt alloys for lathe tooling

[Jimsehr]

For years I machined pure Stellite bearings from bar stock. Very hard and expensive. I had to buy a carbide file to break edges. As the Stellite was harder than a regular file. The chips were saved and ultrasonic cleaned and sold back to the supplier.

 

[ChazzC]

Pricing from Illinois Carbide for Crobalt® Bits

May be different depending on quantity purchased (and sizes & lengths will also affect cost):

$11.00 each for 2, 1/4” Square x 1-1/2” (custom length: standard 2" length +$1 each), for 8mm Height Diamond Tool Holder​

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$12.00 each for 2, 1/4” Round x 1-1/2” (custom length: standard 2" length +$1 each), for 8mm Height Diamond Tool Holder​

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$16.50 each for 4, 5/16” Square x 3”, for regular tool holder​

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$60.00 for 1, TAN-7000 (3/32” x 4-1/2”) Cut-Off Blade​

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$70.00 each for 1, TAN-7002 (1/8” x 4-1/2”) Cut-Off Blade​

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$50 minimum order, shipping by UPS or USPS.​

I'm probably going to get the 1/4" round & square buts and two of the 5/16" x 3" bits (to play with).

Prices on the bits are a little lower than those from Eccentric Engineering (be patient, page loads slowly from the other side of the World), and the TAN-7000 Cut-Off Blade from Village Press (HSM).

 

[59halfstep]

ChazzC - Thank you for the follow up.

 

[verbotenwhisky]

My spare bits came re-packaged, so all I know is what they say:

View attachment 494195

I don’t use Google more than necessary as they know enough about me without giving them more access (I use Safari, and at least Apple leaves me alone). However, a search for “crobalt tool bits” yields this website:

Crobalt® Cast Super Alloy

Crobalt® is a high Cobalt based cast alloy, non-corrosive cutting and wear tool material used to produce standard sized or special tools per customer blueprint.

crobalt.com

which lists a range of sizes of blanks. I tried calling the numbers but got a message that they were closed and to leave a message. D&B says that Illinois Carbide operates under a different name.

HSM has 5/16” round blanks, but the square blanks are backordered:

Tools « Machinist's Resources « Metalworking « Storefront « VP

You can try calling them or calling Gary at Eccentric Engineering and see if he’ll tell you where to get them.

I now use "Duck Duck Go" for a browser and search engine to avoid the trackers.

 

[durableoreo]

Do you grind Crobalt like other high-speed steels?

 

[woodchucker]

I now use "Duck Duck Go" for a browser and search engine to avoid the trackers.

been using it for many years. Like google, it started out like the old google, but more and more it brings up pushed ads for goods, over a good clean search. But way better than google these days. The money has to pay the bills... So there is no free lunch in the long term.

 

[RaisedByWolves]

I, too, have a set of Diamond Tool Holders (and included both square & round Crobalt blanks due to the shipping costs; however, the blanks are made in the U.S. so must be available here from somebody).

I also have a set of A.R.Warner tool holders and use their T-15 inserts in them. This perform very well and can be sharpened by just rubbing the top on a stone. They sell a range of sizes of inserts that will work in other holders as well, but their tool holders are very well made. Here's a comparison of A.R. Warner Tool Holders with others:

I use the Edelstaal T-15 pre formed tool bits and have found them to work great for my needs.

The only problem there is they require a dedicated insert holder and they can be quite pricy.

 

[ChazzC]

Do you grind Crobalt like other high-speed steels?

If you mean on a bench grinder, yes. However, since it is a cast material you don’t dip in water to cool it down (can shatter). Usually not a problem for the Diamond bits as after the first grind you only need to touch them up.

 

[Jeff.64]

Question:
Is using a Crobalt bit in a Diamond Tool Holder an issue?

Here is the last paragraph of the Brazing and Grinding Manual on the Crobalt site:

"To obtain maximum service life from Crobalt® tools, ALWAYS grind the END of tool bits and blades, rather than the top or side, in order to keep the cutting portion on the outer surfaces of the tool casting as furnished. NEVER grind away the outer surfaces so that the cutting portion is at the center of the bit or blade; for with all cast alloy cutting tools, the best cutting properties are located at the surfaces of the casting."

It seems that the cutting portion of the tool bit is on the ground surface when used in the Diamond Tool Holder. Maybe I'm not understanding the use case.

 

[woodchucker]

Question:
Is using a Crobalt bit in a Diamond Tool Holder an issue?

Here is the last paragraph of the Brazing and Grinding Manual on the Crobalt site:

"To obtain maximum service life from Crobalt® tools, ALWAYS grind the END of tool bits and blades, rather than the top or side, in order to keep the cutting portion on the outer surfaces of the tool casting as furnished. NEVER grind away the outer surfaces so that the cutting portion is at the center of the bit or blade; for with all cast alloy cutting tools, the best cutting properties are located at the surfaces of the casting."

It seems that the cutting portion of the tool bit is on the ground surface when used in the Diamond Tool Holder. Maybe I'm not understanding the use case.

No it's a recommended tool.
If you read it correctly the tool is perfect for the diamond holder, since you don't grind away the top of the material, you are grinding the end, not the surface.