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Whining End Mill

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ddickey

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I have this new 1" Niagara rougher end mill I acquired.
Of course I had to get an end mill holder for it.
Mistake as it is unusable even at the lightest cut.
Made a short vid on a piece of scrap.
 

T Bredehoft

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That style is primarily used for side cutting. Yeah, I know, its called an End Mill, but... the interupted flutes make for excellent roughing on the sides.

I dont have audio so I don't run videos. can't hear anything.
 

JimDawson

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Two problems that I see, turning too fast and not enough feed. :) And you are doing a climb cut on a manual machine, so you have that working against you also.

Try approaching from the left side of the material, about 1/4 inch depth of cut, about 1/4 inch width of cut, and around 350 RPM.

It really requires a pretty solid setup and machine to run an endmill that large. That end mill is capable of running full depth and full width through a chunk of steel.
 

ddickey

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Okay I'll give it a try later.
I agree my Bridgeport clone is probably not rigid enough.
 

cbellanca

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That style is primarily used for side cutting. Yeah, I know, its called an End Mill, but... the interupted flutes make for excellent roughing on the sides.

I dont have audio so I don't run videos. can't hear anything.
Okay I'll give it a try later.
I agree my Bridgeport clone is probably not rigid enough.
 

cbellanca

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Roughing mills are not typically used for end cutting. looks and sounds like you are running too fast, and the end flutes are dull. 250 to 350 rpm is about right for mild steel. They are great for side cutting and cutting slots.
 

4ssss

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That isn't whining, that's chatter. Send that one out for sharpening.
 

ddickey

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Tried a piece of aluminum 7075 i think it was.
.100" DOC 750 rpm and also 350 rpm same sound.
According to Tom these are for side milling so will hang onto it for those jobs but will probably not use it for anything else.
 

mikey

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Duane, that is chatter. In aluminum, rpm should be about 1600 -1800 rpm and feed should be in the 0.0045 IPT range. Roughers can be fed faster than a finisher. If you prefer manual feed, feed it so that you have a slight positive resistance to feed and I bet that chatter will clear up.
 

ddickey

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1600 Mike with a 1" HSS cutter?
 

mikey

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Cutting speed for a full radial diameter cut as you're taking using a rougher with Tin coating is 468 sfm per Niagara Cutter. 468 X 3.82 / 1" = 1787 rpm. I figured going a bit slower and feeding a bit faster would do the trick.

Edit: I often slot aluminum with a rougher on my Sherline mill. Of course, it is only a HSS coarse pitch 4 flute 3/8" diameter roughing end mill but I take full diameter depths of cut and run at 2800 rpm, the top speed my mill will run at. I feed manually and it cuts through aluminum easily with no chatter. Would probably work even better if I could get more than 4000 rpm but I can't. Maybe give it a try?
 
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ddickey

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I tried Mikey, no dice. The chatter just reaches a much higher pitch.
I'm going try a 3/4" end mill next. Maybe later tonight yet.
 

mikey

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Hmmm, something is not right. Have you looked at the tips of the cutter under magnification? If any of the tips are damaged, that's your problem. I know its new but have a look anyway because a rougher should not be giving you these issues.
 

ddickey

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I will have a look. I only have I think 10x to look.
My thought too, something is not right here.
 

ddickey

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Hmmm, something is not right. Have you looked at the tips of the cutter under magnification? If any of the tips are damaged, that's your problem. I know its new but have a look anyway because a rougher should not be giving you these issues.
They look perfect Mikey.
I tried a very good used .75" Minicut with an end mill holder. It was fine at .100" but at .200" significant chatter.
Then tried the same end mill in an R8 collet, no problem @.200"DOC.
By the way the 1" Niagara is a five flute. Would that contribute to chatter?
 

benmychree

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You are using the right tool for the wrong job, or vice versa; use a regular end mill.
 

ddickey

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So roughing or corn cob end mills are used for side milling and end mills are used for either. Is there a specific roughing type end mill made fir end milling?
 

JimDawson

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Normally an insert type endmill can be used to remove material quickly. Versatile also because you can use inserts that are designed for the material that you are cutting. I think they are available at least down to 1/2 inch. My son has a 1 1/2 inch that he uses to rip through aluminum. 6000 RPM and about 150 IPM feed, 0.100 - 0.250 depth of cut.
 

mikey

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I can only surmise that either that rougher is bigger than your mill can handle or it is not being held rigidly enough. Do you have an ER-40 chuck that you can try it with?
 

benmychree

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So roughing or corn cob end mills are used for side milling and end mills are used for either. Is there a specific roughing type end mill made fir end milling?
I would use a ordinary two flute end mill.
 

Bob Korves

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I would test the rigidity of the tool and collet mounting, first by just wiggling the end mill. Tool could also be indicated and wiggled, not yanked, looking for runout. Niagara makes very good end mills, some of the finest available. You may have damaged it by not using a deep enough feed, and rubbing dulled the cutting edges. Just guessing on all of this, each test is worth many expert (or not so expert) opinions...
 

ddickey

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I'll try a 2 flute tonight. I have an R8-ER32 but not a 40.
.75" wavy end mill. Starts at .100" DOC and end up at .200" DOC
 

JimDawson

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Those two videos tell a story. If that is the same end mill then I would be taking a hard look at the endmill holder. The endmill holder has a lot more stick out than the collet so that is a factor. But does the holder fit the spindle taper properly? Is the holder bore oversize? Are the spindle bearings right on the edge of being loose? I have some cheaper holders and they tend to have more chatter than my collet holders.

Try less width of cut, maybe 40% or so of the endmill diameter. I find that the depth of cut makes a big difference in chatter. I did a cut a while back that at one diameter deep did not chatter, and at two diameters deep the chatter was unacceptable. Changing feed and speed made no difference. Also for the most part, I try to use an endmill that has a length of cut that is just over the depth that I need to cut, keeps everything as short as possible.
 

ddickey

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Good question on the holder. The 1" is cheap Asian but the .75" is a quality Taiwan made holder.
 

mmcmdl

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Tried a piece of aluminum 7075 i think it was.
.100" DOC 750 rpm and also 350 rpm same sound.
According to Tom these are for side milling so will hang onto it for those jobs but will probably not use it for anything else.

4 flute rougher on Aluminum ? It's going to load up on you quickly ! 2 flute for aluminum and keep it lubricated . I was using a 1" corn cob last night going thru 15-5 ss 32RC . Cut it like butter . ( on a full size mill )
 

ddickey

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What mill do you have? How did you hold the end mill?
 

mattthemuppet2

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If you're using a 1" endmill on an R8 machine, that means one of those uber-stickout 1" endmill holders where all of the endmill will be outside of the spindle. I'd stick to a 1/2" rougher and you'll be fine. Why do you need to run a 1" end mill? You're not going to be able to use it's potential on a Bridgeport type machine. I have several different roughers for my 6x26 - 3fl coarse for aluminium and 4fl fine for steel. They work fabulously, especially the 1/2 3fl coarse in aluminium, that just plows through material.
 

ddickey

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Why, simply because I had one.
I didn't realize R8 spindle wouldn't be rigid enough.
 
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