Indexable lathe tools

Thanks, Ed. What Don wrote describes my work too; one-off jobs, carbide only when HSS fails. Thus I need one grade that will get the job done even if it isn't the best choice. It doesn't have to stay sharp very long.
Next question. Has anyone used the cheap diamond saw blades to sharpen inserts?
Jim Wilkins
Reply to
Jim Wilkins
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My understanding is that the most wear resistant grades are the low numbers and the highest strength grades are the high numbers. So you use C2 for Cast Iron, which does not have high strength, and you use C6 for Steel which does have high strength. I am not sure where I got this idea, so if anyone has better information please post it.
Dan
Reply to
dcaster
On Fri, 25 Jan 2008 10:43:51 -0500, with neither quill nor qualm, "Ed Huntress" quickly quoth:
Non-member price for one of those articles is $15. Pass.
OK. I confess to not having done much along that line yet.
I'm looking for general knowledge about the various alloys or formulations, what each is used for, and why. The majority of my work is wood, but I expect to acquire a mini-mill and mini-lathe later this year.
-- You cannot depend on your eyes when your imagination is out of focus. -- Mark Twain
Reply to
Larry Jaques
Oh cripes. I forgot about that. Sorry. I'll find something better.
You'll note that micrograin and submicrograin carbides have caught hold in woodworking tools, too. In addition to their toughness, I think the property they're looking for there is their ability to take a much sharper edge than conventional carbides.
Do you have Machinery's Handbook? I think they discuss the various carbide grades there. A new edition ought to cover micrograin and submicrograin -- if they've been keeping up.
I have to run now but I'll check my 26th Edition when I get back.
-- Ed Huntress
Reply to
Ed Huntress
On Fri, 25 Jan 2008 13:03:08 -0500, with neither quill nor qualm, "Ed Huntress" quickly quoth:
Yeah, flaunt your numerous memberships to us.
Yes, I do and will check...ten minutes and I found nothing. Hmmm...
Mine's a 14th, born the same year I was, 1953. It might not have what we're looking for.
-- You cannot depend on your eyes when your imagination is out of focus. -- Mark Twain
Reply to
Larry Jaques
Gee, I'll bet a 1953 edition is real useful for info on submicrograin carbides.
The 26th Edition isn't a lot better. It just mentions them, and it sounds like15- or 20-year-old info. It says their first uses were in woodworking, and their metalcutting applications are for low speeds and high feedrates. Not any more, pard'.
Eh. I'm short on research time now but it's a worthwhile project. Remind me in a week and I'll dig out my old contacts to see what gives.
Oh, for anyone interested in grades of carbide for different applications: The old "cutter-class" designations, C2 - C9 or whatever, aren't even reported in the 26th Edition anymore. It was always an arbitrary scale that had nothing to do with the formulation of the carbide itself. It was based on applications (C9 for fine finishing, C2 is supposedly tough, etc.) and it was up to the manufacturer to rate them. So there is no consistency in the cutter-class scale.
Here's one more modern table, based on the ISO designations with some reference to cutter-class. It contains some info on micrograins:
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I'll see if I can find something better next week.
-- Ed Huntress
Reply to
Ed Huntress
I use 12L14 for almost everything we make in our production shop. It is so much easier to achieve better results.
Reply to
Jon
On Fri, 25 Jan 2008 14:46:53 -0500, with neither quill nor qualm, "Ed Huntress" quickly quoth:
Yeah, all the "modern" stuff!
Feh! I'm a bit of a fan of consistency.
Excellent.
Danke mucho, signore.
-- Bite off more than you can chew, then chew it. Plan more than you can do, then do it. -- Anonymous
Reply to
Larry Jaques
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I haven't used them enough to give a real thorough evaluation, but the positive rake inserts I got from Rouse Arno seem to work very nicely. The inserts I have are razor sharp.
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I got a set of inserts & holders on sale at the Eastec machine tool show 2 years ago. I got a set with 3/8" square shanks, and liked them so much I ordered the 1/2" square set before the show discount expired.
Doug White
Reply to
Doug White
Arno was promoting their positive-rake inserts back when I was active in the field, so they probably have plenty of experience with them. The first time I saw really sharp, thin-edged positive-rake carbide inserts was in the mid-90s. They were made by some German company, and I was absolutely amazed that those things could hold up in production cutting. But they do, apparently, and there are a lot of new cutting tool products out there that should answer problems we've had with hard tool materials on flexible old machine tools.
The one I'd really like to see is tools made of Crucible CPM Rex 121. It's a sort of extreme high-speed steel, sometimes called a "bridge" material because it bridges the performance and application gap between HSS and carbide. It ought to be the answer to lots of applications that need sharp, tough, positive-rake cutters that are hard enough to cut hardened steel on a small lathe. With that and a high-cobalt submicrograin carbide we could fill in a lot of gaps.
Crucible only makes (or made) 121 in small quantities, and those go to wear-part and press tooling. The last time I talked to them, which was maybe four years ago, they planned to make it available for cutting tool manufacturers once they got their production up. Maybe they already have.
It's a powder-metallurgy high-speed steel with extremely high percentages of carbide-forming alloy, particularly vanadium.
-- Ed Huntress
Reply to
Ed Huntress
Absolutely. The leaded alloys don't behave at all like common low carbon steel. If you've worked with materials like Stressproof or even 303 S or Se, you likely know they cooperate much better, too.
Harold
Reply to
Harold and Susan Vordos
However..its not great for welding.
Gunner
Reply to
Gunner
Keywords:
This sounds pretty neat. I've been wondering why somebody doesn't make HSS (or exotic steel alloy) inserts that could be used with carbide tooling. It may just be that the fabrication costs don't match up with the perceived market. Being able to pop a sharp insert into a holder without having to take things apart & regrind your tool strikes me as a big advantage.
Doug White
Reply to
Doug White
Well, there are HSS inserts for use with the same toolholders used for carbide inserts. Their applications in industry are relatively few, however. There aren't a lot of applications in production turning that require HSS, that can't be satisfied with some kind of hardmetal or ceramic insert. A key is having extremely rigid machine tools with adequate horsepower and spindle speeds, which is what most of industry is using today.
-- Ed Huntress
Reply to
Ed Huntress
Not even recommended. That's pretty common for the majority of free machining materials. What makes them free machining generally makes welding difficult or impossible.
Harold
Reply to
Harold and Susan Vordos
However..it solders and brazes well.
Gunner
Reply to
Gunner
Then the converse of that should make old weight bars the most weld able steel in existence Gerry :-)} London, Canada
Reply to
Gerald Miller

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