Re: [CAD_CAM_EDM_DRO] Re: wrong guy, but have servo question.

Hi all:
What I was actually referring to here, was the consequence of having the
quill extended, not the presence of the "knuckles for tipping the head
(although you are quite correct that their presence reduces the stiffness of
the mill also.)
As an example of what I mean, try this test:
Take a 1" dia 2 flute carbide cutter, and take a 0.125" pass in prehardened
4140 or P20, with the quill up and clamped. Stick an indicator against the
quill as you take the cut and watch it bounce around.
Now drop the quill its full 5" and clamp it lightly, so you can still slide
it up and down with the handle.
Try taking the same cut again, and you will soon see what I mean; if you
don't instantly destroy the cutter, that is.
I have found very few quill type mills that can pass this test, in fact the
only one I can remember was a Pedersen mill that had a quill about 6"
diameter and a massive head that was not tiltable.

Cheers

Marcus

-----Original Message-----
From: Jon Elson <jmelson@...>
To: CAD_CAM_EDM_DRO@egroups.com <CAD_CAM_EDM_DRO@egroups.com>
Date: Monday, November 27, 2000 4:35 PM
Subject: Re: [CAD_CAM_EDM_DRO] Re: wrong guy, but have servo question.

>
>
>JanRwl@... wrote:
>
>> In a message dated 27-Nov-00 10:00:20 Central Standard Time,
>> implmex@... writes:
>>
>> > The basic physics you are up against, is that an extended quill flops

around

>> > in X and Y, because it is cantilevered out so far.
>> > This makes heavy cutting impossible, and accuracy a hit or miss affair,
>> > depending on how far out the quill happens to be sticking.
>> >
>>
>> Ya suppose that's why the "store-bought" CNC mills have "fixed"

quill-frames,

>> i.e., one can't "swing" the quill at an angle???
>
>Yes, absolutely, that does make the machine more stiff (but less
>'flexible' in doing odd procedures.)
>
>Jon
>
>
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