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Best APKT 1604 insert for AR500?

Dope

Cast Iron
Joined
Jan 16, 2016
Hello friends,

I primarily mill AR450/AR500 on my two old manual Cincinnati mills (vertical and horizontal). Huge amounts of material removal (100lbs per workpiece at times) using indexed EMs and facemills. So far the best I've used is Kennametal MP91 grade inserts but I'm looking for superior options if anyone has any. I've really enjoyed Iscar's 908 grade as well but they only come in the smaller 1003 size.

Much appreciated for any advice and experience!

EDIT: I'd also entertain other insert designs if they are really exceptional for my application, I just have a lot of apkt cutters
 
You might want to look into an SEKN or similar if you're doing a lot of heavy material removal. I've always found them to be about the best roughing insert there is. The high lead angle means you can feed a little harder, and they are some of the smoothest running cutters I've ever used. If I remember correctly they are a good bit cheaper than APKT also, and you get 4 cutting edges instead of 2.
 
surprised you recommend such and "ancient" insert and the high angle for hard steel. not doubting you, just curious. what would all the new geometries be for?
 
surprised you recommend such and "ancient" insert and the high angle for hard steel. not doubting you, just curious. what would all the new geometries be for?

Costing you more money! Also unnecessary on a manual machine. The high angle isn't necessarily as high as you assume, there are different edge prepa for different materials, the same as all the newer styles of insert. But for just banging off stock, SEKN is hard to beat.
 
You might want to look into an SEKN or similar if you're doing a lot of heavy material removal. I've always found them to be about the best roughing insert there is. The high lead angle means you can feed a little harder, and they are some of the smoothest running cutters I've ever used. If I remember correctly they are a good bit cheaper than APKT also, and you get 4 cutting edges instead of 2.

Interesting, but are they good for extremely hard/tough materials like AR500? I only get maybe 90 minutes of cutting out of an EM/insert before they are completely destroyed (broken corners, etc).
 
i remember destroying tpnk (k2885) inserts on hardox 450. it fortunately has not come up since then, but i would tend to round inserts and a negative land for roughing (burry the land). you might get 6 edges out of them. some extreme heat coating also.
 
Cutting tough materials like AR plate, tool life often comes down to edge prep more than anything. It is critical for abrasive type materials. I have cut plenty of AR400 and AR500 with SEKN milling cutters. They work great, just like pretty much any other cutter with a good high positive rake. Keep the bulk of the insert positive with a small negative or radiused edge prep and it cuts just like anything else, with the caveat that you must use lower cutting speeds of course. Don't use a sharp edge or it will crumble. And do not let the tool dwell or rub, feed it fairly heavily. And yes, you will wear out inserts... Cutting tougher/harder materials generally comes with that trade-off. You get 90 minutes, but how many cubic inches of material removal? The minutes spent tell me nothing.

TPKN inserts are a poor choice, you want to use a corner angle that is as obtuse as possible. The more acute that angle, the weaker the insert. Cutting hard materials puts a heavy load on the insert. If you use the ones with the little wiper flat that is at least a little better.

The toughest part in my experience is if you try to tap it. Better to cut an oversized hole and weld a softer steel plug in the hole location and drill and tap that instead.
 
...
They work great, just like pretty much any other cutter with a good high positive rake. Keep the bulk of the insert positive with a small negative or radiused edge prep and it cuts just like anything else,
.

How does one know what edge you get when ordering most tools? At one time a letter following (none,A,B,C) but this abandoned now.
T-lands still called out sometimes but often even this unknown.
Other than the fingernail test which shows upsharp how many can check or know the cutting edge a .001,.003,.006?
Bob
 
How does one know what edge you get when ordering most tools? At one time a letter following (none,A,B,C) but this abandoned now.
T-lands still called out sometimes but often even this unknown.
Other than the fingernail test which shows upsharp how many can check or know the cutting edge a .001,.003,.006?
Bob

Most people don't even pay attention to this and just order off the shelf stuff and assume that's all you can get. If you actually call and ask, the manufacturers will give you whatever they have that's most suitable if you call and get through to the technical support line. Other than that, you do it yourself. I have a microscope and can measure the edge prep pretty readily.

There are still a few companies that offer varying geometry and edge prep in a set range too, like Seco, Sandvik and Kennametal have some I know of for sure. They don't generally tell you what that edge prep actually is, just that it's for heavy, medium or light cutting.
 
It's been nearly 2.5 years but I figured I'd post a follow up. I have tried dozens of insert shapes and grades and nose radii and all that in the meantime. Kennametal, Sandvik, Iscar, Ingersoll, Carboloy, Valenite, Tungaloy, Seco, Korloy, Kyocera and Widia if I remember correctly.

Right now, for APKT 1604xx, the best choice I have found is Ingersoll's IN2005 grade. It's got an H10-H30 rating for hard materials which is about the highest I've ever seen for carbide inserts (same as Iscar IC908 but they only make it in the smaller APKT formats like 1003). Reasonably priced and they sell it in a 160408 and 160432 if you need a big radius.

Those two are the best choices for large and small format APKT cutters, IMO. Maybe I'll update in another 2.5 years.
 
It's been nearly 2.5 years but I figured I'd post a follow up. I have tried dozens of insert shapes and grades and nose radii and all that in the meantime. Kennametal, Sandvik, Iscar, Ingersoll, Carboloy, Valenite, Tungaloy, Seco, Korloy, Kyocera and Widia if I remember correctly.

Right now, for APKT 1604xx, the best choice I have found is Ingersoll's IN2005 grade. It's got an H10-H30 rating for hard materials which is about the highest I've ever seen for carbide inserts (same as Iscar IC908 but they only make it in the smaller APKT formats like 1003). Reasonably priced and they sell it in a 160408 and 160432 if you need a big radius.

Those two are the best choices for large and small format APKT cutters, IMO. Maybe I'll update in another 2.5 years.
yep definately no magic one size fits all solution. ive ran APKT16 mm and they work well, then ran some R390 inserts, but at $25 a pop, they aren't cheap when buying 10 in a pack to put 5 pcs in a 2" facemill. although, feeding it hard and fast if the machine can have the HP always helps.
 
Costing you more money! Also unnecessary on a manual machine. The high angle isn't necessarily as high as you assume, there are different edge prepa for different materials, the same as all the newer styles of insert. But for just banging off stock, SEKN is hard to beat.

A modern, thick, negative rake, double sided square insert like Sandvik's 345 massively outperforms SEKN for MMR. Comfortably 3x the feed per tooth with very nearly the same light cutting action.

Similarly, APKT inserts are a pretty bad choice for MMR of high tensile steels, because of their hard cutting action and fragility.

For shoulder milling such materials really good choices are Sandvik 490 (single sided square) and Tungaloy DoForce-Tri (double sided triangle).
 
A modern, thick, negative rake, double sided square insert like Sandvik's 345 massively outperforms SEKN for MMR. Comfortably 3x the feed per tooth with very nearly the same light cutting action.

Similarly, APKT inserts are a pretty bad choice for MMR of high tensile steels, because of their hard cutting action and fragility.

For shoulder milling such materials really good choices are Sandvik 490 (single sided square) and Tungaloy DoForce-Tri (double sided triangle).

Not in AR plate it doesn't. And you need an extremely stout machine to push a double negative square insert milling cutter very hard. As well as a rock solid setup and a rigid worklpiece. If all those bases are covered and you're not cutting AR plate, I agree.

Unless you're talking about some newfangled insert that is actually positive geometry due to surface topography. Then it probably will beat SEKN on AR plate. Will cost a lot more though.
 
Not in AR plate it doesn't. And you need an extremely stout machine to push a double negative square insert milling cutter very hard. As well as a rock solid setup and a rigid worklpiece. If all those bases are covered and you're not cutting AR plate, I agree.

I have filled skips with Hardox chips using these tools, I know what works.

These are not negative rake in the conventional sense, they are thick, moulded top positive edge negative rake inserts. The difference in cutting force between a 345 and a SEKN is negligible, but the 345 is massively stronger, has much better pocket security, twice as many edges, and is available in modern grades.

Same goes for the DoForce-Tri - negative rake but with a deep moulded top for a high positive shear cutting action.

The 490 is a more traditional positive rake shallow moulded insert, but performs well.

Stout machine, yes, but that comes with the territory cutting these materials.
 
I have filled skips with Hardox chips using these tools, I know what works.

These are not negative rake in the conventional sense, they are thick, moulded top positive edge negative rake inserts. The difference in cutting force between a 345 and a SEKN is negligible, but the 345 is massively stronger, has much better pocket security, twice as many edges, and is available in modern grades.

Same goes for the DoForce-Tri - negative rake but with a deep moulded top for a high positive shear cutting action.

The 490 is a more traditional positive rake shallow moulded insert, but performs well.

Stout machine, yes, but that comes with the territory cutting these materials.

I thought you were talking about the *old* double negative squares like SNG - Your first post didn't mention that bit in a way I recognized, I don't know those newer inserts. Like I said at the end in *my* first post, I totally agree if you're talking about the "fake negative" inserts that actually have positive geometry.
 
I thought you were talking about the *old* double negative squares like SNG - Your first post didn't mention that bit in a way I recognized, I don't know those newer inserts. Like I said at the end in *my* first post, I totally agree if you're talking about the "fake negative" inserts that actually have positive geometry.
Yes, sorry for not making that clearer.

This is the 345. It doesn't look that positive, but in practice it has a really smooth cutting action. They're stating a 3mm doc in that image, but I run these at 5-6mm deep pretty much always.
positive-cutting-action_jpg.webp


And the DoForce-Tri. Also a really smooth cutting action, 11mm max DOC.
m_501_b_02.jpg


Both of these are great for brute force MMR, facing and shouldering respectively.
 
A modern, thick, negative rake, double sided square insert like Sandvik's 345 massively outperforms SEKN for MMR. Comfortably 3x the feed per tooth with very nearly the same light cutting action.

Similarly, APKT inserts are a pretty bad choice for MMR of high tensile steels, because of their hard cutting action and fragility.

For shoulder milling such materials really good choices are Sandvik 490 (single sided square) and Tungaloy DoForce-Tri (double sided triangle).
Thank you for posting your experiences. One of the insert grades I wanted to try was Sandvik 4220 (H10-H30, wet or dry - which I prefer the latter). I thought about trying their R390 insert but honestly it appeared to just be a slightly modified APKT but at 200% the price (and 500% the price for the cutter bodies). I also looked at the R345 but I generally prefer a square shoulder if I can (lots of slotting and shoulder milling with facemills) and that is a 45 degree insert. I didn't look at the 490 though, I've never used or seen that insert so I don't think I knew it existed. I'm browsing ebay now...

For tungaloy, what grade are you thinking? I didn't find any grades that I thought were on-par with Iscar or Sandvik so I didn't look TOO hard at their stuff.
 








 
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