Back To Indexable Tooling(AXA)

(If it wasn't for the high bidder, I would have paid just over $60 for

Have you looked through their catalog? Link above.

Wes

I downloaded that catalog a week ago.

But what I'm looking for is a tutorial.

For example, where would I go online to read the definition(with images) of what a negative rake is, and whatit does?

Thanks.

Darren Harris Staten Island, New York.

Your best bet for that and related questions is _Machinery's Handbook_, any year. If you don't have a copy, drive over to the Perth Amboy Public Library. They have one on their reference shelf. There's another one at the New York Public Library's 96th St. Branch. Maybe your local library can get it on a loan. (Call number is 621.802 M.)

If you have other questions of that order about machining, you'll find _Machinery's Handbook_ to be a gold mine.

-- Ed Huntress

I actually have "Machinery's Handbook"(27th Edition).

But I was hoping there was a quick convenient reference guide online.

Thanks.

Darren Harris Staten Island,New York.

Well it generally allows more cutting edges on an insert since no relief is ground in. The downside is that cutting forces are increased requiring a rigid machine. Light machines tend to do best with positive rake cutting tools.

If you look at TPU or TPG insert (triangle positive unground) (triangle positive ground) you will see one side has a larger perimeter than the outer side, that is due to the rake or clearance the tool needs it can be inclined in respect to the centerline of your work piece with out rubbing.

Now a TNG has to be declined in respect to the centerline as not to rub. It will remove metal but now you need a more rigid machine and your stock is subjected to heaver forces.

Look at a wood plane. It is an example of positive rake. The metalworking equivalent of negative rake would be to flip the blade and run plane backwards.

Wes

-- "Additionally as a security officer, I carry a gun to protect government officials but my life isn't worth protecting at home in their eyes." Dick Anthony Heller

My worn 10" South Bend can use negative top rake only for light cuts, which is OK for HSS but apparently not so good for carbide.

Or a scraper.

Several tool company catalogs have descriptions of carbide types and geometry. Their recommendations for turning stainless have worked for me but not the ones for mild or tool steel, so I use HSS.

Jim Wilkins

The MSC catalog has a pretty good tutorial on the subject. I don't know whether the online version has the same detail, but you can look:

I think. I wouldn't spend much time on negative rake inserts unless you have a pretty solid lathe. Remember that you have to force the cutting tool into the work to get it to cut. If you are "forcing" a positive rake insert into the work, the included angle of the edge is less than 90 degrees (somewhat acute). A negative rake cutting edge is has a 90 degree angle or more. Less acute, (less "sharp") = more pressure required to get it to cut = more bending of the the machine before tool gets pushed into the work = less precision of setting a cut. Try taking a 1/2 thou cut with even a TPU (7° positive rake) insert. Then try again with a 12° HSS tool. See which one takes of the metal. If they both do, then you can think about "N".

I know because I have an Atlas 10" lathe, Pete Stanaitis

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Searcher7 wrote:

place:

>>(If it wasn't for the high bidder, I would have paid just over $60 for

NOPE - a cabinet makers scraper, properly prepared, actually has a high degree of positive rake, even if only for a very short distance.

Gerry :-)} London, Canada

I haven't seen anyone properly burnish a scraper edge since jr high school wood shop in the '50's. The scrapers we can buy now at HD are only good for removing paint.

Jim Wilkins

Buy a Sandvik hand scraper. It's made just right for turning over the edge and burnishing. I also have some Stanleys, but they aren't as hard.

-- Ed Huntress

Husqvarna is more appropriate for the kind of woodworking I do.

Jim Wilkins

Hmmm. Nice finish. d8-)

We have one of those guys who carves Indian chiefs and eagles out of standing stumps with a chainsaw in my town (and he's an ice sculptor and taxidermist, too). It's hard to believe the accuracy and detail he can achieve. I think he's a Stihl man.

-- Ed Huntress

So is everyone saying that my AXA 12N with my mini-lathe is not a good idea for any metals?

Thanks.

Darren Harris Staten Isalnd, New York.

I don't speak for everyone, but I was saying that negative rake doesn't always work WELL on my old lathe. Or maybe I haven't learned how to use it. Try it, see what happens.

Jim Wilkins