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Posted by F. George McDuffee on April 2, 2008, 8:10 pm
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wrote:
>>>I have a Sherline vertical mill (the 5000 series) and I keep having a
>>> problem with my aluminum workpiece pulling loose from the mill vise.
>>> I have NEVER had very good luck getting the Sherline mill vise to hold
>>> aluminum terribly well. Is this a deficiency of their mill vise?
>>> Would a different mill vise solve the problem? Is it possible that .
>>> 010" cuts are too much?
>
>> I cannot imagine what you are doing to cause this problem from your
>> information supplied, but it is highly unusual. Please describe what you are
>> doing and how.
>
> I don't know whether there there was more to what you posted --
>both quoted samples that I have seen have not shown more, so I don't
>know whether the following applies or not.
>
> If the workpiece is sticking out of the vise by a height in
>excess of perhaps four times the height of the jaw grip, then there is a
>major problem with leverage working against you.
>
> If you are trying to hold something withoutparallel faces
>against the jaws, such as round stock stood on end in the milling vise,
>there is a great chance that it will slip under cutting forces -- even
>on a machine as small as a Sherline.
>
> A rectangular workpiece is better held with the wide dimension
>across the width of the vise, and the end resting on the bottom of the
>vise.
>
> A workpiece with an irregular surface in contact with the jaws
>is more likely to slip, because there is really very little material in
>direct contact with the jaws. This can be helped somewhat by putting
>cardboard between the workpiece and the jaw surface so it produces a
>larger contact patch.
>
> So yes, more detail about the workpiece and how you are
>attempting to hold it would help us to figure out what is wrong.
>
> Good Luck,
> DoN.
===============
Good observation/question.
I had assumed (and so apparently had everyone else) that the
problem was a rectangular part in the vise, for no good reason.
It may indeed be round, irregular, etc.
Question to original poster -- what is the shape of the aluminum
piece you are trying to clamp?
Unka' George [George McDuffee]
-------------------------------------------
He that will not apply new remedies,
must expect new evils:
for Time is the greatest innovator: and
if Time, of course, alter things to the worse,
and wisdom and counsel shall not alter them to the better,
what shall be the end?
Francis Bacon (1561-1626), English philosopher, essayist, statesman.
Essays, "Of Innovations" (1597-1625).
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Posted by on April 5, 2008, 9:39 am
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On Apr 2, 6:10 pm, F. George McDuffee <gmcduf...@mcduffee-
associates.us> wrote:
> wrote:
>
>
>
> >>>I have a Sherline vertical mill (the 5000 series) and I keep having a
> >>> problem with my aluminum workpiece pulling loose from the mill vise.
> >>> I have NEVER had very good luck getting the Sherline mill vise to hold
> >>> aluminum terribly well. Is this a deficiency of their mill vise?
> >>> Would a different mill vise solve the problem? Is it possible that .
> >>> 010" cuts are too much?
>
> >> I cannot imagine what you are doing to cause this problem from your
> >> information supplied, but it is highly unusual. Please describe what you are
> >> doing and how.
>
> > I don't know whether there there was more to what you posted --
> >both quoted samples that I have seen have not shown more, so I don't
> >know whether the following applies or not.
>
> > If the workpiece is sticking out of the vise by a height in
> >excess of perhaps four times the height of the jaw grip, then there is a
> >major problem with leverage working against you.
>
> > If you are trying to hold something withoutparallel faces
> >against the jaws, such as round stock stood on end in the milling vise,
> >there is a great chance that it will slip under cutting forces -- even
> >on a machine as small as a Sherline.
>
> > A rectangular workpiece is better held with the wide dimension
> >across the width of the vise, and the end resting on the bottom of the
> >vise.
>
> > A workpiece with an irregular surface in contact with the jaws
> >is more likely to slip, because there is really very little material in
> >direct contact with the jaws. This can be helped somewhat by putting
> >cardboard between the workpiece and the jaw surface so it produces a
> >larger contact patch.
>
> > So yes, more detail about the workpiece and how you are
> >attempting to hold it would help us to figure out what is wrong.
>
> > Good Luck,
> > DoN.
>
> ===============
> Good observation/question.
>
> I had assumed (and so apparently had everyone else) that the
> problem was a rectangular part in the vise, for no good reason.
>
> It may indeed be round, irregular, etc.
>
> Question to original poster -- what is the shape of the aluminum
> piece you are trying to clamp?
>
> Unka' George [George McDuffee]
> -------------------------------------------
> He that will not apply new remedies,
> must expect new evils:
> for Time is the greatest innovator: and
> if Time, of course, alter things to the worse,
> and wisdom and counsel shall not alter them to the better,
> what shall be the end?
>
> Francis Bacon (1561-1626), English philosopher, essayist, statesman.
> Essays, "Of Innovations" (1597-1625).
Square workpiece.
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Posted by on April 5, 2008, 11:51 am
Please log in for more thread options >
> >>I have a Sherline vertical mill (the 5000 series) and I keep having a
> >> problem with my aluminum workpiece pulling loose from the mill vise.
> >> I have NEVER had very good luck getting the Sherline mill vise to hold
> >> aluminum terribly well. Is this a deficiency of their mill vise?
> >> Would a different mill vise solve the problem? Is it possible that .
> >> 010" cuts are too much?
> > I cannot imagine what you are doing to cause this problem from your
> > information supplied, but it is highly unusual. Please describe what you are
> > doing and how.
>
> I don't know whether there there was more to what you posted --
> both quoted samples that I have seen have not shown more, so I don't
> know whether the following applies or not.
>
> If the workpiece is sticking out of the vise by a height in
> excess of perhaps four times the height of the jaw grip, then there is a
> major problem with leverage working against you.
>
> Good Luck,
> DoN.
>
> --
> (too) near Washington D.C. |http://www.d-and-d.com/dnichols/DoN.html
> --- Black Holes are where God is dividing by zero ---
Good catch. I put in a piece of 6061 scrap that I cut off the
workpiece with a bandsaw, one
small enough that it was just barely above the jaws--and I was able to
run an end mill across the
surface just fine. At .010" slices, it worked just great--not a
single snag, stoppage, or loosening.
I tried one pass at .015" and while it didn't stop, I could see that
this was the upper limit of what
I could do.
When I turned that scrap on end, so that there was about 3" sticking
above the jaws, the old
problems started to appear.
So, does this mean that if you have a workpiece that is fairly big,
you should get yourself a mill
vise with very tall jaws? Does someone make a mill vise for
micromills with varying height jaws?
Obviously, you should turn a workpiece the direction required to get
maximum grip from the jaws, and
mill vertically rather than horizontally--but sometimes that's just
not possible.
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Posted by Backlash on April 5, 2008, 1:04 pm
Please log in for more thread options You can add a vise stop to the end of your vise on the fixed jaw by drilling
and tapping a hole for a flat plate retained by a bolt. This sticks up above
the vise jaws and provides a physical stop for the thrust pressure of
milling. Another bolt with a locknut tapped into the upper part of the stop
provides localized pressure at the top edge of the plate. A horizontal mill
can snatch items right out of the vice without using this type of endstop to
take the forces. A Bridgeport generally pushes parts over more slowly, but
can bust a cutter for you..
RJ
>>
>> >>I have a Sherline vertical mill (the 5000 series) and I keep having a
>> >> problem with my aluminum workpiece pulling loose from the mill vise.
>> >> I have NEVER had very good luck getting the Sherline mill vise to hold
>> >> aluminum terribly well. Is this a deficiency of their mill vise?
>> >> Would a different mill vise solve the problem? Is it possible that .
>> >> 010" cuts are too much?
>> > I cannot imagine what you are doing to cause this problem from your
>> > information supplied, but it is highly unusual. Please describe what
>> > you are
>> > doing and how.
>>
>> I don't know whether there there was more to what you posted --
>> both quoted samples that I have seen have not shown more, so I don't
>> know whether the following applies or not.
>>
>> If the workpiece is sticking out of the vise by a height in
>> excess of perhaps four times the height of the jaw grip, then there is a
>> major problem with leverage working against you.
>
>>
>
>> Good Luck,
>> DoN.
>>
>> --
>> (too) near Washington D.C.
>> |http://www.d-and-d.com/dnichols/DoN.html
>> --- Black Holes are where God is dividing by zero ---
>
> Good catch. I put in a piece of 6061 scrap that I cut off the
> workpiece with a bandsaw, one
> small enough that it was just barely above the jaws--and I was able to
> run an end mill across the
> surface just fine. At .010" slices, it worked just great--not a
> single snag, stoppage, or loosening.
> I tried one pass at .015" and while it didn't stop, I could see that
> this was the upper limit of what
> I could do.
>
> When I turned that scrap on end, so that there was about 3" sticking
> above the jaws, the old
> problems started to appear.
>
> So, does this mean that if you have a workpiece that is fairly big,
> you should get yourself a mill
> vise with very tall jaws? Does someone make a mill vise for
> micromills with varying height jaws?
>
> Obviously, you should turn a workpiece the direction required to get
> maximum grip from the jaws, and
> mill vertically rather than horizontally--but sometimes that's just
> not possible.
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Posted by on April 5, 2008, 4:26 pm
Please log in for more thread options > You can add a vise stop to the end of your vise on the fixed jaw by drilling
> and tapping a hole for a flat plate retained by a bolt. This sticks up above
> the vise jaws and provides a physical stop for the thrust pressure of
> milling. Another bolt with a locknut tapped into the upper part of the stop
> provides localized pressure at the top edge of the plate. A horizontal mill
> can snatch items right out of the vice without using this type of endstop to
> take the forces. A Bridgeport generally pushes parts over more slowly, but
> can bust a cutter for you..
>
> RJ
Help me to visualize this a bit more. The vise has jaws held in place
by a few screws.
I can replace the current jaws with a plate that uses the same
threads, but goes up several
inches higher than the current jaws. What's this "bolt with a locknut
tapped into the
upper part of the stop"? What does this bolt screw into?
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>>> problem with my aluminum workpiece pulling loose from the mill vise.
>>> I have NEVER had very good luck getting the Sherline mill vise to hold
>>> aluminum terribly well. Is this a deficiency of their mill vise?
>>> Would a different mill vise solve the problem? Is it possible that .
>>> 010" cuts are too much?