End mill cut diameters completely out -of-the-park

snowshooze · Sep 10, 2018

Hi Guys!
I was cutting a 1/4" keyway with a 3/16" end mill today, and broke my end mill.
I said, ok.. that one has paid out... I gotta nother one there in the pile..
I pulled a brand new sealed Imco 3/16" 4 flute outta the box.. tossed it into a practically brand new Teknics side lock cat 40 holder...
And as I recently added Renishaw Probe and tool-setter to that mill, I sent it to the tool setter for length and diameter, so I could work with real sizes in CAD/CAM.
This brand new end-mill come up as .1542" diameter.
That is just below 5/32"
Now, 5 or 6 years ago, when I was a completely old world machinist... I would have been screaming and throwing shit.
I am glad I caught this.
But, it isn't the first time.
I measured by Renishaw the last one, supposed to be 3/16" as well, and came up with a number... .1866"
Can anybody tell me what the heck is up with this???
Thanks again!
Mark

Guest · Sep 10, 2018

End Mills have tolerances, look them up on McMaster-Carr the tolerances are listed.

Bobw · Sep 10, 2018

You should have been able to pick that up visually...

So what does the tool actually measure??? Is this a tool problem,
or a probe problem??

litlerob1 · Sep 10, 2018

Mistakes happen at every level, there isn't a question about whether that is true or not.

But you haven't posted what your Micrometer told you. Or Comparator, or Height Gage and Vee block. Whatever method you use to gather a second measurement.

R

snowshooze · Sep 10, 2018

Bobw said:
You should have been able to pick that up visually...

So what does the tool actually measure??? Is this a tool problem,
or a probe problem??

I did.
Probe is fine, finished part all aces, but if I did a slot on the bridgeport, I would have expected a 3/16" end-mill to cut on-size, or a bit over.

snowshooze · Sep 10, 2018

Bobw said:
You should have been able to pick that up visually...

So what does the tool actually measure??? Is this a tool problem,
or a probe problem??

As stated.
And, it did the job correctly.
The tool is not the size it is labeled as.

litlerob1 · Sep 10, 2018

snowshooze said:
As stated.
And, it did the job correctly.
The tool is not the size it is labeled as.

That sucks, but occasionally it happens. Sometimes you order a Cheeseburger and you get a Big Mac. :icon_bs:

Bobw · Sep 10, 2018

It was seriously .154??? .1866 I wouldn't bitch about, but .154??

Imco is generally pretty damn good.. I hope you picked up the phone.

I've only ever called Imco once, and it was for tech support.. It was easily the
best tech support I've ever gotten.. I called about some A286, and when I realized the
guy was pretty f'n smart, I asked him about 13-8, since I was running TONS of it at the time.
This guy actually knew what I was talking about, he actually TESTED CUTTERS IN THESE MATERIALS,
he wasn't just looking at some numbers in a catalog. I was impressed, but this was years ago.

snowshooze · Sep 10, 2018

Bobw said:
It was seriously .154??? .1866 I wouldn't bitch about, but .154??

Imco is generally pretty damn good.. I hope you picked up the phone.

I've only ever called Imco once, and it was for tech support.. It was easily the
best tech support I've ever gotten.. I called about some A286, and when I realized the
guy was pretty f'n smart, I asked him about 13-8, since I was running TONS of it at the time.
This guy actually knew what I was talking about, he actually TESTED CUTTERS IN THESE MATERIALS,
he wasn't just looking at some numbers in a catalog. I was impressed, but this was years ago.

Really. I shit you not.

Mike1974 · Sep 10, 2018

I would guess it was just a mis-labeled 5/32" end mill. Got put in the wrong box or whatever. Not that I have used too many "odd" sizes, but they are out there. A quick search and McMaster shows 9/64, 5/32, and 11/64.

snowshooze · Sep 10, 2018

Mike1974 said:
I would guess it was just a mis-labeled 5/32" end mill. Got put in the wrong box or whatever. Not that I have used too many "odd" sizes, but they are out there. A quick search and McMaster shows 9/64, 5/32, and 11/64.

So, it came in UNDER a true 5/64" as well, slightly.
It should have been over in Renishaw, allowing for holder runnout...

litlerob1 · Sep 10, 2018

It's a $10.00 Endmill. I'm not saying it's acceptable, but if you're that worked up about it, you're bound for a Stroke within a year.

snowshooze · Sep 10, 2018

It ain't a $10 end mill.
I said Imco.
Not Enco.

litlerob1 · Sep 10, 2018

Oh my, so it's a $30.00 Endmill, whoopee!!! Get used to it. You're going to drop them, and chip the corner off, and use a dirty collet, and pile drive it into a part, and not retract it and rapid it through the side of a part. These things happen. Someone on the Imco end made a mistake, that also happens from time to time.

I can see the vein in your forehead pulsing from here. Relax, you can send it back.

I see now that this is just a rant, I will excuse myself.

R

crazygoat · Sep 10, 2018

Obviously got put in the wrong box. Shit happens. I am surprised you couldn't tell by looking, though.

snowshooze · Sep 10, 2018

litlerob1 said:
Oh my, so it's a $30.00 Endmill, whoopee!!! Get used to it. You're going to drop them, and chip the corner off, and use a dirty collet, and pile drive it into a part, and not retract it and rapid it through the side of a part. These things happen. Someone on the Imco end made a mistake, that also happens from time to time.

I can see the vein in your forehead pulsing from here. Relax, you can send it back.

I see now that this is just a rant, I will excuse myself.

R

Everyone like a little ass.
Nobody likes a smart ass.

litlerob1 · Sep 10, 2018

snowshooze said:
Everyone like a little ass.
Nobody likes a smart ass.

You may want to block me now.

guest · Sep 10, 2018

.002" under is a lot for a little end mill like that.

I've had recent end mill quality problems, but it was taper in the shank- .0012" taper on a 1" shank. Went from .9993" to 1.0005" above the set screw flat. Couldn't load it into a holder.

SeymourDumore · Sep 10, 2018

Mislabeled box.
Obviously the shank was a 3/16, meaning same box is used for both, 3/16 and 5/32 - non straight shank so only the label is different.

Get another one and send this back, or get another one and keep it. No big deal at all.

What I DO consider to be a big deal however is that you use your CAM to compensate for dimensional variations.
That one, I cannot stomach.

Spruewell · Sep 10, 2018

“What I DO consider to be a big deal however is that you use your CAM to compensate for dimensional variations.
That one, I cannot stomach.”

Isn’t that what all that fancy software is for? To help lazy machinists be more productive in spite of themselves?
Writing your programs with cutter comp would allow you to take care of those variations rather easily right at the machine too.

End mill cut diameters completely out -of-the-park

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