Help Facing 4140 to a Smooth Finish

Hi Everyone!

Please see the attached picture. I am facing two sides of this annealed 4140 being held in a vice. The part is 7/8" tall X 1-3/8" wide X 2" long. The face sticking out the side of the vice is faced with a 1/2" em at 100 ipm and the surface finish is good...maybe 30Ra". The top, however, is faced with a 1-1/2" face mill at 26ipm (about .004" ipt) and the surface finish is more like 150Ra" or so. I am looking for something like a 60 Ra".

I am using an Iscar four-insert HOF face mill with "general purpose" face milling inserts (the only ones available for this cutter, apparently.) The machine is a dual contact Speedio in good shape. I am only taking off about .007" and I see the machine mark swirls going both ways, which I think means the spindle is very perpendicular to the axis movement during that op.

I was going to try getting a face mill body that can accommodate a wiper insert. I have heard they can handle 2X the "normal" feed rate of the roughing cut, so maybe I could go TWICE as fast yet achieve the target surface roughness. I was also wondering if I should try zipping over it with the 1/2" end mill...since it's so much smaller than the face mill it would use higher RPMs and thusly higher ipm...plus maybe I could use one with like a .060" corner radius to help with the finish?

Soooooo, here's my questions:

1. Can anyone recommend a 1-1/2 to 2" face mill that would accommodate a wiper insert...that is, if the stories are true regarding feed rate and surface roughness.

2. Does it make sense to try using the bottom of an end mill instead?

Thank you!

Take a heavier finish cut like .02", and flood coolant. You don't mention the SFPM that you're running it at, but I would be around 800sfpm for starters, feedrate seems fine, maybe a tad on the slow side but you're shooting for a particular micro so you might even have to slow it down a tad.

Using the bottom of an endmill will work, but only if you're going for smoothness and not caring about cosmetics, it won't look all that great.

can i make a suggestion. finishing facemill
EDP: 2917710 - Part Number: EF6J-02R01 - Series: EF6J Hi-Feed Finishing Face Mill

https://ssl.ingersoll-imc.com/resources/pdf/new-169-3_gold-max-4_ffin.pdf

Mtndew said:

Take a heavier finish cut like .02", and flood coolant. You don't mention the SFPM that you're running it at, but I would be around 800sfpm for starters, feedrate seems fine, maybe a tad on the slow side but you're shooting for a particular micro so you might even have to slow it down a tad.

Using the bottom of an endmill will work, but only if you're going for smoothness and not caring about cosmetics, it won't look all that great.

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Thanks! I’m at like 700SFM with the face mill. Oh yeah, I’m using air. I didn’t even try coolant because I always thought air leaves it shinier, but obviously it’s easy enough to try coolant. I really can’t take off more than the .007” unless I want to start with thicker material. The parts get vibrated so as long as the swirlies go away we win.

can i make a suggestion. finishing facemill
EDP: 2917710 - Part Number: EF6J-02R01 - Series: EF6J Hi-Feed Finishing Face Mill

https://ssl.ingersoll-imc.com/resources/pdf/new-169-3_gold-max-4_ffin.pdf

vr6 said:

can i make a suggestion. finishing facemill
EDP: 2917710 - Part Number: EF6J-02R01 - Series: EF6J Hi-Feed Finishing Face Mill

https://ssl.ingersoll-imc.com/resources/pdf/new-169-3_gold-max-4_ffin.pdf

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.01-.03 per tooth! That’s what I’m talking about!! I wonder if I have the balls to put a 3” cutter body in a 30-taper brother, though....hmmmm. It really shouldn’t be a problem with the low depth of cut as long as it’s touched off properly and Im using the right pull stud, nyuk nyuk! (re long broken pull stud thread from a month ago ). Thank you!

Nerdlinger said:

.01-.03 per tooth! That’s what I’m talking about!! I wonder if I have the balls to put a 3” cutter body in a 30-taper brother, though....hmmmm. It really shouldn’t be a problem with the low depth of cut as long as it’s touched off properly and Im using the right pull stud, nyuk nyuk! (re long broken pull stud thread from a month ago). Thank you!

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the first link i sent you is for a 2" cutter, not a 3", just an fyi

vr6 said:

the first link i sent you is for a 2" cutter, not a 3", just an fyi

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Ah! Radical! Thank you! The "flier" said 3.00" to 8.00" but I now see the 2.00" cutter you are referring to. Have you used these? I have no experience with wipers...do they last about as long as a cutting insert?

As said before .007 is a pretty light cut for an inserted tool. If you only have .007" of material to work with I would try hand lapping one insert really sharp and only run that one insert. It's slow but I have gotten some super nice finishes on light cuts when in a pinch doing that.

Nerdlinger said:

.01-.03 per tooth! That’s what I’m talking about!! I wonder if I have the balls to put a 3” cutter body in a 30-taper brother, though....hmmmm. It really shouldn’t be a problem with the low depth of cut as long as it’s touched off properly

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I think the max diameter is 80mm?
I use a 2-1/2" facemill in my Brother... but of course I'm only taking .01" in 6061.
No way I'd chance a heavy cut with a tool that size.

Okay I just got off the horn with Ingersoll and the GoldMax finishing tool has two inserts for it...a "high feed" insert that is good up to .040" depth and a "finishing" insert that is good up to .008" so it should be perfect for my application. They claim 8 Ra" so we'll put that to the test! I am looking at the 2" cutter body that will fit my existing 30-taper arbors.

Nerdlinger said:

Okay I just got off the horn with Ingersoll and the GoldMax finishing tool has two inserts for it...a "high feed" insert that is good up to .040" depth and a "finishing" insert that is good up to .008" so it should be perfect for my application. They claim 8 Ra" so we'll put that to the test! I am looking at the 2" cutter body that will fit my existing 30-taper arbors.

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the DFHL205 has a larger wiper where as the L001 does not, hence why the apmx is less on 205. that being said, either one will work for you application but the 205 has its limits then the L001 insert.

the wiper length on the 205 is pretty much all the way on the insert. if you have a distributor you are currently working with, you can reach out to them and your local ingersoll rep to setup a test

I would go with a bigger facemill. 3” maybe.
You want the inserts to hit the edge of the stock more perpendicular so you’re not dragging the chip across the face.
Also, you want a big enough cutter to span the whole part without dragging the trailing edge across it. That makes the finish look like crap for sure.

SECO Turbo with wiper and ALL THE SFM! I don't know what it is about 4140 but it seems like the more I crank up the rippums the better it looks.

Well I'll be damned! I couldn't sleep last night, waiting for that cutter to arrive! The part on the left is with the new Ingersoll cutter/wiper inserts (.020ipt) and the one on the right is with general-purpose face milling inserts (.004ipt). Thank you for your help! This tool has already earned its spot in my arsenal (assuming the inserts hold up!)

Your probably not going to get a great finish from annealed 4140, I find I get a better finish after heat treatment.

Nerdlinger said:

Well I'll be damned! I couldn't sleep last night, waiting for that cutter to arrive! The part on the left is with the new Ingersoll cutter/wiper inserts (.020ipt) and the one on the right is with general-purpose face milling inserts (.004ipt). Thank you for your help! This tool has already earned its spot in my arsenal (assuming the inserts hold up!)

View attachment 277159

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glad it worked out, and that was me when you called into Ingersoll btw

Nerdlinger said:

Well I'll be damned! I couldn't sleep last night, waiting for that cutter to arrive! The part on the left is with the new Ingersoll cutter/wiper inserts (.020ipt) and the one on the right is with general-purpose face milling inserts (.004ipt). Thank you for your help! This tool has already earned its spot in my arsenal (assuming the inserts hold up!)

View attachment 277159

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Wow looks great!

Nerdlinger, So what exactly did you end up with for a face mill and inserts? I have been thinking about a face mill and those results look really nice.

lanb said:

Nerdlinger, So what exactly did you end up with for a face mill and inserts? I have been thinking about a face mill and those results look really nice.

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EDP: 2917710 - Part Number: EF6J-02R01 - Series: EF6J Hi-Feed Finishing Face Mill
EDP: 2920841 - Part Number: DFH324L205 Y IN2530 - Series: DFH

max doc is .008 with the L205 inserts. using the L001 insert, you can run to a max DOC .040