indexable end mill question

[rolland]

I purchased one of indexable end mills from Enco, I need to do some facing on a piece of 4140 for a project. I have never used one like this as I have always used standard end mills or a fly cutter so........... I got to thinking (a dangerous habit I have) it might come in handy. I ordered the correct inserts for alloy steel but having never used one I hoped to solicit some tips on its use. It is the 1 1/4 diameter http://www.use-enco.com/CGI/INSRIT?PMAKA=422-3012
Any help would be apprecated.

[KiddZimaHater]

If you have a large, rigid mill it should be a breeze.
You might have problems with a small mill.
Lock your spindle in the raised position, and raise the knee to meet the work.
NEVER MILL WITH THE QUILL EXTENDED.
1000 RPM. Feed it by hand.
If power feeding about .010 - .015 per rev.

[Black_Moons]

Well, that looks somewhat similar to my carbide insert holder, though yours looks to have more rake.. (mine is negative rake! very lame but great for the extra cutting edges and roughing), One thing i'll say if its anything like mine, you basicly can NOT sidemill with it. something like 0.03" depth of cut before it starts sounding like a jack hammer insted of an endmill. Width of cut can easily be 3/4 the width of the endmill, or even the entire thing (though you might get a worse finish with a full width pass)

with enough 0.03 depth passes, the sides may however achive a good finish if you locked the unused axis of your mill.

On mine, I managed to run it up to the full 1600rpm of my mill against mild steel (1" diamiter for my endmill), though that was a little bit excessive, finish degraded past 900 rpm and the scalding hot chips flying around my shop where hard to dodge and melted into plastic objects. at 900 rpm finish was better and the chips where a little easyer to dodge.. and peel outta my plastic tool containers :P
(Again, mine is negative rake so it can REALLY handle the SFM/RPM, but some modren carbide inserts are CRAZY) yours appears to be posative rake by a few degrees (no insert geometry to assist) so you might wanna stay a little lower on the SFM scale, like 900rpm to start with and see how the inserts/finish fare.. and your mill. (900rpm * 1.25" * PI / 12" = 294SFM, About HSS speed * 3 for mild steel, and *2 for aluminium.. you could go much faster in aluminum, maybe a touch slower in harder steels like tool steels (4140 I believe counts as harder tool steel?) depending on insert quality and type..

[DaHui]

No problem, just try it on some scrap first. I have face mills in 2", 3" and 4" that I use on my bridgeport all the time. Just don't expect to move a lot of material in one pass...especially if the inserts don't have a positive chip breaking geometry. Okay, the 4" I have is pretty excessive but it was a steal on ebay.

I run the 2" mill (4 insert) anywhere from 800-1200 RPM on aluminum or steel. In terms of feed, just push it till the chips are the right color (on steel) or measure them till you get about .003 chip thickness. Most of the time I just go by the sound.

[beanbag]

Sorry to say, I think you got the wrong tool. You should either get one that takes APKT inserts and leans them back (for some effective helix angle) if you want to do any side milling, or one of the 45 degree face mills that takes the square inserts (if you want to do facing only). Glacern sells both types, as an example. Return your tool if you can.

[TGTool]

Sorry to say, I think you got the wrong tool. You should either get one that takes APKT inserts and leans them back (for some effective helix angle) if you want to do any side milling, or one of the 45 degree face mills that takes the square inserts (if you want to do facing only). Glacern sells both types, as an example. Return your tool if you can.

Ha ha. Not only that, look carefully at the picture on the Enco link. It's left hand rotation!!

Actually I presume they just flipped a digital photo L/R to fit their catalog but it does give one pause.

[JTToner]

I have a similar face mill I've been using in my knee mill with, I believe, TT32x inserts. Face or side milling, I've had good results in 6061, 4140, and A2. Caution, have shields in place , those blue chips come off fast, furious, and HOT. And, at high rpm will sling them all over the shop. For shields I just use Lexan panels on those cheapo HF or Enco magnetic holders for dial indicators. Not terribly elegant, but functional. Oh, forget Chinese inserts. Get name brand European or US made inserts.

[rolland]

Thanks for the input, guess I will need an flame proof suit for the chips. I have a piece of 4140 that needs squared up to start a project its 2 1/2 square by 3 inches long so my smaller end mills take forever. I will give this a try and adjust from there.

[Carld]

Why don't you use a flycutter? You can run the flycutter at about 1000 rpm and probably take .050" DOC and make a cut the full width with no trouble at all and the flycutters are cheaper.

[PaulT]

Sorry to say, I think you got the wrong tool. You should either get one that takes APKT inserts and leans them back (for some effective helix angle) if you want to do any side milling, or one of the 45 degree face mills that takes the square inserts (if you want to do facing only). Glacern sells both types, as an example. Return your tool if you can.

Beanbag is giving good advice here. Mills using the APKT type inserts cut much better on BP sized machines than the old TPG inserts. The geometry of the insert just works better, its a much more modern design.

They work really well on both steel and aluminum with the right inserts, you can get some ground and polished APKT inserts for aluminum that give really good surface finishes. I'd send the TPG mill back, even if you have to eat the shipping costs.

Enco really should stop promoting TPG tooling to home shop users, pro's have moved away from it a long time ago, the newer design inserts just work better, both on small and big machines.

Paul T.