Tool Bits, What's Best

[Spin Doctor]

At work we've got Vasco Supreme's. Just curious what's the best grade HSS lathe tool bits. We're loking at ordering a large lot for making up standard form tools

[wierdscience]

Now theres one of those Ford,Chevy,Dodge questions again.

So,I'll cut to the chase,almost any domestic HSS will be excellent,and the Polish made stuff ain't bad either.

Now when you get into additives like cobalt all bets are off.

[SGW]

Cleveland Mo-Max Cobalt are good. But "best" all depends on what you're doing to do with them. You might do perfectly well with M2, and anything more exotic would be a waste of money.

[Spin Doctor]

Been doing some research on alloy composition of various grades and such. Turns out Vasco Supreme is T-15 tool steel. The uses thet we put HSS tool bits to work in are primarily form tools such as radius, chamfer anf threading on manual machines in quick change tool post set-ups. Does any body know a good tool steel guide for application in producing cutting tools.

[Rustybolt]

Spin. We used M2(easy to heat treat) or carbide tipped. Made many thousands of ports with M2, cutting 11L17 with lots of coolant.

[spope14]

5 to 10% cobalt bits have been the best for me.

For general turning and chamfering tools, look at carbide "Microbits". They are about the same cost. For form tools however, after 17 years of teaching, I make all my form bits out of 10% cobalt because they are very shock resistant and have long between grind life. The old M2 bits I started with have since been ground into dust. My cobalt bits are now about ten years old and still going........

[Thrud]

T-15 is the toughest toolbit you can get, has the highest red hardness and is the toughest to grind. Excellent for the toughest jobs or interupted cuts - holds edge longest. Not recommended if grinding is a problem. CBN wheels work best, then premium Norton Norzon ceramic wheels.

If you can grind it, buy T-15. Almost as good as carbides.

[hsmike]

Spin,
Vasco Supreme isn't available anymore. It's a trade name for Teledyne Vasco's T-15. It was also what you call conventional T-15. Most place today are using PM T-15. The PM stands for powdered metal, Crucible Steels being the most popular, (CPM T-15). PM grinds allot easier than conventional but is 50/60% more expensive.
M-2 and M-4 (62/64 Rc hardness) are more for toughness, M-42 (67/68 Rc) has the red hardness (can take more heat) T-15 has excellent wear resistance plus some red hardness.
About Cobalt: There are at least 6 grades of High Speed Steel that have 5% Cobalt , ranging in price from $3.50/Lb to $22.00/Lb. T-15 is in the upper range. You get what you pay for.
M-42 has 8% Cobalt.
If you can find T-15 at a reasonable price they are great tools.
Did you try to find HSS blanks for your form tools, or do you need the versatility of the toolbits?

[sidneyt]

" T-15 is the toughest toolbit you can get, has the highest red hardness and is the toughest to grind. Excellent for the toughest jobs or interupted cuts - holds edge longest. "
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"The low toughness rating of T15 steel excludes its application for operations which involve shock or sudden variations in load."

Machinery's Handbook, 19th Ed, page 2001

Actually M2 is more resistant to shock than T15 or M42, but it is less resistant to abrasion and has a lower red-heat hardness.

[neonman]

Ok guys, since we are talking about tool bits, here's a question. I recently acquired a cast iron engine kit, and a few of the castings have that HARD crust on them. What kind of bit do y'all use on that? I've been using 5% cobolt, and he hard stuff takes off the edge faster than my bench grinder does.