[gbowne1]

Hi all!

I was just wondering if anyone knew what the standard corner radii on the corners of a .500 (l) x 500 (w) x .1875 (t) TiN Carbide insert are?

I have a couple dozen custom inserts that need to be made.. and need to know what they are so I can apply them to my AutoCAD 2009 .dwg/.dxf.

What makes them custom is the diameter AND angle/depth of the coutersink/chamfer of the center hole.

Greg

[PixMan]

Is this a lathe insert or a milling insert that you're asking about?

With the hole in the middle, it sounds like you might be referring to a SNMG 53x insert, where "x" is the operative for which radius is on the tip. There is no "standard:, though a SNMG 532 is probably more common. That would be a "2/64ths" (.03125) radius. An SNMG 533 would be .0473", a 531 would be .0156".

Does this help?

[Eurisko]

We use CNMG 432 inserts for lathe work. The inserts are not square, but have two 80 degree corners and two 100 degree corners. The 100 degree corners are used for facing, the 80 degree corners are used for turning and boring.

The first digit is the diameter of the inscribed circle in 1/8ths of an inch.
The second digit is the thickness of the insert in 1/16ths of an inch.
The last digit is the corner radius in 1/64ths of an inch.

A CNMG 432 also fits the specs for your insert. They also have a center mounting hole.

The proper radius to use is dictated by the part you are machining. If a flange or shoulder specifies a maximum radius of .020, we could use a 431 insert (1/64 radius) or a 430 insert (not a zero radius, but almost).

The smaller radii tend to wear more quickly. The larger radius inserts (CNMG 433) tend to chatter a bit more. Overall, I'd say that a CNMG 432 insert (1/32 radius) is a good choice for routine lathe work.

[gbowne1]

These are used on a special 3" diameter 45° face mill cutter that I have mounted on a 40 taper tool. These are not a "CNMG". They are square, not a 80° diamond shape. Whats the differece between a insert with 53x and 43x?

Thanks,
Greg

[CarbideBob]

1/2 x 1/2 x 3/16 is a xxxx-43x insert. (first number is size in 1/8ths of an inch, 4/8ths =.500)
Standard rads are #2=.032, #3=.047, #4=.062.
Rad size is third letter in 64ths of an inch so a .032 rad is a xxxx-432 insert. These are the most common but if you're having special inserts made you can get any radius size you want (.005 min. rad size).
If you know the dimension across the corners you can calculate what size rad is on the insert. (ACdim=1.4142xSidedim - (.8284xRadsize) )

We know the first letter is an "S" since you said it's a square so that's a Sxxx-432.

Second letter is "P" for 11 degree positive (bigger on top than bottom) or "N" for negative (same size top and bottom). There are several different letters for different rake (side clearance) angles.

What's so special about your holes? There are several different standard countersinks available. Custom holes are drilled by hand in the green state and are not cheap in small quantities.

[gbowne1]

The special thing is the diameter and the angle of the countersink.. they were made to fit the special torx pin-screws in the cutter.

I'll probably have them made in a couple different radii.

I have a AutoCAD .dwg/.dxf of it that needs to be edited. It needs to have the dimensions changed to decimal, and insert all the other dimensions, angle dimensions, etc. in decimals, plus the addition of the radii.

Yes, the insert is a Positive rake insert. I can't remember if it's 7°, 9° or 11°.

Greg

[CarbideBob]

Maybe this one.
SPGW-43x has an ISO cylindrical hole for torx screws.
.300 top opening, funnel shaped c-sink, .212 thru hole.
Fits screws with head angles from 40 to 60 degrees.
Bob

[gbowne1]

Yea.. that sounds more like it.

It's a flat top insert with no chipbreaker.

I can show you the drawing if you want. I'm no good with AutoCAD 2009 (still learning it).

Greg

[CarbideBob]

A drawing or picture would make things much easier.:cheers: