Help with APKT inserts

I recently bought a 1 1/2" indexable mill for my Bridgeport. I would like to get some more inserts but am very confused on what to get. I know the inserts for this mill are APKT 1604. I'm looking for inserts for low to medium carbon steel cutting. After looking at so many suppliers on the web and EBay, I can't figure out what all the different APKTxxxxx numbers mean. Would like to keep a eye out on eBay and find a deal on some but don't want to get the wrong inserts. Any help is appreciated.

I'm going to keep it as simple as possible, at the possible risk of oversimplifying. APKT1604 is the size and shape of the inserts you need. Don't buy any inserts with different letters or different four numbers. Exception: APET and APMT can substitute for APKT. Do not buy ADKT inserts. Do not buy 1806, 1505, or 1003 inserts.

There may be letters or numbers after the first four numbers. For example: APKT 1604 PDTR ME14 F40M . Those are specifying things like the insert corner treatment, edge hone, carbide grade, chipbreaker shape, etc. Most of those extra letters and numbers are proprietary to the insert maker, so you'd have to look them up in a catalog for the specific brand. In that particular example, PDTR is actually industry standard, meaning "0 degree wiper lead angle, 15 degree wiper clearance angle, T-land edge hone, right-handed cutting only".

You can find a milling insert nomenclature chart (for the non-proprietary bits) here, among many other places.

Havic9 said:

I recently bought a 1 1/2" indexable mill for my Bridgeport. I would like to get some more inserts but am very confused on what to get. I know the inserts for this mill are APKT 1604. I'm looking for inserts for low to medium carbon steel cutting.

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So what you're saying is basically ANY APKT 1604 insert should work for you, thats easy. If they are specific to Aluminiiuuim they will work fine in CRS, if they are specific to SS they will work fine for you, if they are specific to super alloys they will work fine for you.

The info. is out there, depending on whether you want a Phd. or not, is how much effort you should put into it.

Well, not exactly any APKT will work in aluminum. The coating may be an issue. Coatings that contain aluminum such as TiAIN can cause galling and welding of work to the insert.

Tom

sfriedberg is correct any APKT1604, APMT1604 and APET1604 Insert will fit your current cutter body. The most common APKT insert is a APKT160408 (or it can be listed as a APKT1604PDSR) Here is what each letter stands for:
A=Shape of Insert (85 Degree Parallelogram)
P=Side Reak Angle (11 Degrees)
K=Tolerance (K is tighter tolerance on height, thickness & IC than M)
T=Hole, Chipbreaker (Single Sided w/ Chipbreaker)
16=Edge Length (.629")
04=Thickness (.1875")
08=Corner Radius (.031")
P=Cutting Edge Angle (90 Degree)
D=Relief Angle (15 Degrees)
S=Edge Prep (Chamfered+R-Honed)
R=Tool Hand (Right Hand)

Any Coated Insert that matches the description above would work well for you in Carbon Steel, we would have inserts for Steel/Stainless Steel on promo right now as a option:
APKT168 PMY BM351 - ToolHIT

TDegenhart said:

Well, not exactly any APKT will work in aluminum. The coating may be an issue. Coatings that contain aluminum such as TiAIN can cause galling and welding of work to the insert.

Tom

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True dat Dog. What I wrote was that an Alu. specific insert will work fine in cold roll steel, not optimal for life, but it'll work. Not the other way around.

R

Great information guys. Thanks.

Hi sfriedberg, from those parameters, which one is affects the surface roughness of the workpiece?

Surface roughness is going to be controlled by the combination of the insert corner radius, wiper flat (if any) and your feed per insert. If the insert has a wiper flat (e.g., PDTR) and your feed does not exceed the width of the wiper flat (and all your inserts protrude from the body the same amount), then you should get a low roughness finish.

If there's no wiper flat, a small radius (sharp) corner, and you're using a lot of feed, you will carve ripples in the part surface.

You can also get a crummy finish by using inappropriate cutter surface speed, especially on gummy or tough materials. But that's mostly independent of the insert geometry.

Don't forget the insert tolerance. A high insert will create a scallop.

This handy chart will help explain whats going on with the numbers.

I'll give you the easy solution to picking the right insert..
And it won't fry your brains, and it won't take
a doctoral thesis to understand.

Pick up the phone and call Curtis(ExKenna on this site) and say

"Hey Curtis, I need an APKT 1604 that does XXX and YYYY and ZZZZ"

Then it shows up on my door step, and does XXX and YYYY and ZZZZ..

There are people that do this for a living. Also every cutting tool
you've ever bought, a little bit of that money you've spent is used
to have tech people on staff that know this stuff..

I haven't chosen an insert out of a catalog for myself in probably
10 years.. I know what basic edge prep I want, light hone, medium
hone, dead sharp etc.. I know when I want it really high positive and
when I don't.. I know when I need an aggressive chip breaker, and when
I don't... What I don't know how to do is to transfer that knowledge
into a big giant long code to get the insert I want..

Then nevermind the coating and substrate and how that works with your
insert geometry... That is way over my paygrade.. And there are people
that know this stuff inside and out, and they only charge you money
if you buy stuff from them..

Just my 2 cents on the subject. I have more important stuff to do
(like play on PM) than digging through a catalog trying to figure
out what insert I need to buy.

I don't like using APKT style inserts on a BP, I tried it once, never again.

With a aluminum specific inserts their OK in aluminum, but I've never had much luck with them in steel, on either Fadala or a Makino I've never got near the recomended speeds/feeds/depths as recomended without the cutter sounding and feeling like it was trying to beat the machine to death.